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Buccal
Terms modified by Buccal Selected AbstractsEnamel microhardness and bond strengths of self-etching primer adhesivesEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2010Olabisi A. Adebayo Adebayo OA, Burrow MF, Tyas MJ, Adams GG, Collins ML. Enamel microhardness and bond strengths of self-etching primer adhesives. Eur J Oral Sci 2010; 118: 191,196. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci The aim of this study was to determine the relationship between enamel surface microhardness and microshear bond strength (,SBS). Buccal and lingual mid-coronal enamel sections were prepared from 22 permanent human molars and divided into two groups, each comprising the buccal and lingual enamel from 11 teeth, to analyze two self-etching primer adhesives (Clearfil SE Bond and Tokuyama Bond Force). One-half of each enamel surface was tested using the Vickers hardness test with 10 indentations at 1 N and a 15-s dwell time. A hybrid resin composite was bonded to the other half of the enamel surface with the adhesive system assigned to the group. After 24 h of water storage of specimens at 37º°C, the ,SBS test was carried out on a universal testing machine at a crosshead speed of 1 mm min,1 until bond failure occurred. The mean ,SBS was regressed on the mean Vickers hardness number (VHN) using a weighted regression analysis in order to explore the relationship between enamel hardness and ,SBS. The weights used were the inverse of the variance of the ,SBS means. Neither separate correlation analyses for each adhesive nor combined regression analyses showed a significant correlation between the VHN and the ,SBS. These results suggest that the ,SBS of the self-etch adhesive systems are not influenced by enamel surface microhardness. [source] Effect of enamel matrix proteins (Emdogain®) on healing after re-implantation of "periodontally compromised" rootsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 10 2003An experimental study in the dog Abstract Objective: The present experiment was performed to assess whether Emdogain® applied on the root surface of extracted teeth or teeth previously exposed to root planning can protect the tooth from ankylosis following re-implantation. Material and Methods: The experiment included two groups of dogs, including five animals each. The root canals of all mandibular third premolars (3 P 3) were reamed and filled with gutta-percha. A crestal incision was placed from the area of the second to the fourth premolar. Buccal and lingual full thickness flaps were elevated. With the use of a fissure bur, the crown and furcation area of 3 P 3 were severed in an apico-coronal cut. The distal and mesial tooth segments were luxated with an elevator and extracted with forceps. Group A: The mesial and distal segments of 3 P 3 were air dried on a glass surface for 60 min. The roots from the right side were conditioned and exposed to Emdogain® application. The roots from the left side received the same treatment with the exception of Emdogain® application. The mesial and distal tooth segments were re-implanted and the crown portions were severed with a horizontal cut and removed. The buccal and lingual flaps were mobilized and sutured to obtain complete coverage of the submerged roots. Group B: A notch was prepared in each root, 4,5 mm apical of the cemento-enamel junction. The area of the root that was located coronal to the notch was scaled and planned. The roots in the right side of the mandible were treated with Emdogain®, while the roots in the left side served as controls. After 6 months of healing, the dogs were killed and blocks containing one root with surrounding tissues were harvested, and prepared for histological examination, which also included morphometric assessments. Thus, the proportions of the roots that exhibited signs of (i) replacement (ii) inflammatory and (iii) surface resorption were calculated. Results and Conclusion: It was demonstrated that healing of a re-implanted root that had been extracted and deprived of vital cementoblasts was characterized by processes that included root resorption, ankylosis and new attachment formation. It was also demonstrated that Emdogain® treatment, i.e. conditioning with EDTA and placement of enamel matrix proteins on the detached root surface, failed to interfere with the healing process. Zusammenfassung Zielsetzung: Untersuchung, ob Emdogain®, wenn es auf die Wurzeloberfläche extrahierter Zähne oder von Zähnen, die zuvor eine Wurzelglättung bekommen haben, appliziert wird, die Zähne nach Reimplantation vor Ankylose schützen kann. Material und Methoden: Die Studie wurde bei 2 Gruppen von Hunden durchgeführt, die je 5 Tiere umfasste. Die Wurzelkanäle aller 3. Prämolaren des Unterkiefers (3 P 3) wurden aufbereitet und mit Guttapercha gefüllt. Ein Schnitt auf dem Limbus alveolaris wurde vom 2. zum 4 Prämolaren geführt. Bukkal und lingual wurde ein Vollschichtlappen mobilisiert. Mit einem Fissurenbohrer wurden die 3 P 3 mit einem Schnitt in koronoapikaler Richtung im Bereich der Krone und der Furkation geteilt. Die distalen und mesialen Zahnsegmente wurden mit einem Elevator luxiert und mit einer Zange extrahiert. Gruppe A: Die mesialen und distalen Segmente von 3 P 3 wurden auf einer Glasoberfläche 60 min lang luftgetrocknet. Die Wurzeln der rechten Seite wurden konditioniert und mit Emdogain® beschickt. Die Wurzeln der linken Seite erhielten die gleiche Behandlung mit der Ausnahme, dass keine Applikation von Emdogain® erfolgte. Die mesialen und distalen Wurzeln wurden reimplantiert und die Kronenanteile durch einen horizontalen Schnitt getrennt und entfernt. Die bukkalen und lingualen Lappen wurden mobilisiert und durch Naht ein vollständiger Verschluss der reimplantierten Wurzeln erreicht. Gruppe B: In jede Wurzel wurde 4,5 mm apikal der Schmelz-Zement-Grenze eine Kerbe präpariert. Der Bereich der Wurzel, der koronal dieser Kerbe lag, wurde gescalt und wurzelgeglättet. Die Wurzeln der rechten Unterkieferseite wurden mit Emdogain® behandelt, während die Wurzeln der linken Seite als Kontrolle dienten. Nach einer Heilung von 6 Monaten wurden die Hunde getötet und Blöcke, die eine Wurzel und das umgebende Gewebe enthielten, gewonnen und für die histologische Untersuchung präpariert, die auch morphometrische Befunde einschloss. Es wurden also die Anteile der Wurzeln berechnet, die Zeichen von (i) Ersatz- (ii) entzündlicher und (iii) Oberflächenresorption zeigten. Ergebnisse und Schlussfolgerungen: Es wurde gezeigt, dass die Heilung von reimplantierten Wurzeln, die extrahiert und von vitalen Zementoblasten befreit worden waren, durch Prozesse charakterisiert war, die Wurzelresorption, Ankylose und die Bildung neuen Attachments umfassten. Es wurde gezeigt, dass die Behandlung mit Emdogain®, d.h. Konditionierung mit EDTA und Applikation des Schmelz-Matrix-Proteins auf die freie Wurzeloberfläche diesen Heilungsprozess nicht beeinflussen konnte. Résumé Objectif: Cette expérimentation fut réalisée pour déterminer si Emdogain® appliqué sur la surface radiculaire de dents extraites ou de dents préalablement soumises à un surfaçage radiculaire pouvait protéger la dent de l'ankylose après réimplantation. Matériel et Méthodes: L'expérience comprenait 2 groupes de 5 chiens. Les canaux radiculaires de toutes les troisièmes premolaires mandibulaires (3 P 3) furent alésés et bouchés à la gutta-percha. Une incision crestale de la deuxième à la quatrième prémolaire permit de soulever un lambeau de pleine épaisseur vestibulaire et lingual. La couronne et la zone de furcation de 3 P 3 furent découpées à l'aide d'une fraise fissure d'apical en coronaire. Les segments distaux et mésiaux furent luxés avec un élévateur et extraits avec un davier. Groupe A: Les segments mésiaux et distaux de 3 P 3 furent séchés à l'air sur une plaque de verre pendant 60 min. Les racines du coté droit furent préparées et imprégnées d' Emdogain®. Les racines gauches reçurent le même traitement sans application d'Emdogain ®. Les segments mésiaux et distaux furent alors réimplantés et les couronnes découpées par un trait horizontal et éliminées. Les lambeaux vestibulaires et linguaux furent déplacés et suturés pour obtenir un recouvrement complet des racines enfouies. Groupe B: Une entaille a été préparée sur chaque racine, à 4,5 mm en apical de la jonction amélo-cémentaire. La surface de racine située coronairement à cette entaille fut alors détartrée et surfacée. Les racines du coté droit furent traitées par Emdogain® alors que les racines du coté gauche firent office de contrôle. Après 6 mois de cicatrisation, les chiens furent sacrifiés et des blocs contenant une racine et les tissus environnant furent prélevés pour un examen histologique et morphométrique. Ainsi, les proportions de racine présentant des signes de (i) remplacement (ii) d'inflammation et (iii) de résorption furent calculées. Résultats et conclusion: Nous avons démontré que la cicatrisation de racine réimplantées après extraction et élimination des cémentoblastes se caractérisait par un processus qui comprenait résorption radiculaire, ankylose et formation d'une nouvelle attache. Nous avons aussi démontré que le traitement par Emdogain®, c'est à dire conditionnement à l'EDTA et mise en place de protéines de la matrice améllaire sur la surface radiculaire, ne pouvait pas interférer avec le processus de cicatrisation. [source] Buccal and lingual activity during mastication and swallowing in typical adultsJOURNAL OF ORAL REHABILITATION, Issue 1 2003M. J. Casas summary, A non-invasive protocol was developed to assess tongue and cheek movements during mastication and to evaluate the temporal relationship between mastication and the initiation of pharyngeal swallowing. Typical adults (three males and three females) were monitored during chewing. Miniature pressure transducers were bonded unilaterally to the buccal and lingual surfaces of the first mandibular molar and the buccal surface of the first maxillary molar on each subject's preferred chewing side. Surface electromyography of the ipsilateral masseter muscle was recorded as an indicator of jaw-closing activity. Pressure and electromyography (EMG) recordings were time-linked to simultaneous B-mode ultrasound imaging of the oral cavity using a submental, coronal view aligned with the first mandibular molar. The intervals between peak pressure recorded at each pressure transducer and peak jaw-closing activity for each masticatory cycle were not statistically different [analysis of variance (anova), P=0·9856] and displayed large statistical variation. These intervals were not different at the beginning of the trials (hard biscuit) than they were at the completion of mastication when the cookie had been broken down to a paste/puree consistency bolus. The interval between the last chewing stroke and the initiation of swallowing was 0·92 ± 0·34 s). No significant difference existed among subjects for this time interval (anova, P=0·382). [source] Laser-activated fluoride treatment of enamel as prevention against erosionAUSTRALIAN DENTAL JOURNAL, Issue 3 2007J. Vlacic Abstract Background: Erosion is the loss of dental hard tissues from an acidic challenge, often resulting in exposure of dentinal tubules and hypersensitivity to environmental stimuli. Laser-activated fluoride (LAF) therapy with 488nm laser energy has been shown previously to increase the resistance of human enamel and dentine to acid dissolution. The aims of this study were to investigate the action spectrum of LAF in protecting tooth enamel from softening in response to an erosive challenge, and to examine for any temperature change with the treatment. Materials and Methods: Buccal and lingual surfaces of extracted sound molar and premolar teeth were used to prepare matched pairs of enamel slabs (N=10 per group). After application of 1.23% neutral sodium fluoride gel (12 300ppm F ion), slab surfaces were lased with 488, 514.5, 532, 633, 670, 830 or 1064nm wavelength (energy density 15J/cm2; spot size 5mm), then exposed to an erosive challenge (1.0M HCl for five minutes). The Vicker's hardness number (VHN) was recorded before fluoride gel application and again following the acid challenge. Negative controls did not receive laser exposure. Results: All wavelengths of laser light examined provided a protective LAF effect against softening, compared with the negative control surfaces. Conclusion: From these findings, we conclude that the action spectrum of the LAF effect extends across the visible spectrum, providing protection to dental enamel from an erosive challenge. [source] Tissue modeling following implant placement in fresh extraction socketsCLINICAL ORAL IMPLANTS RESEARCH, Issue 6 2006Mauricio G. Araújo Abstract Objective: To study whether osseointegration once established following implant placement in a fresh extraction socket may be lost as a result of tissue modeling. Material and methods: Seven beagle dogs were used. The third and fourth premolars in both quadrants of the mandible were used as experimental teeth. Buccal and lingual full-thickness flaps were elevated and distal roots were removed. Implants were installed in the fresh extraction socket. Semi-submerged healing of the implant sites was allowed. In five dogs, the experimental procedure was first performed in the right side of the mandible and 2 months later in the left mandible. These five animals were sacrificed 1 month after the final implant installation. In two dogs, the premolar sites on both sides of the mandible were treated in one surgical session and biopsies were obtained immediately after implant placement. All biopsies were processed for ground sectioning and stained. Results: The void that existed between the implant and the socket walls at surgery was filled at 4 weeks with woven bone that made contact with the SLA surface. In this interval, (i) the buccal and lingual bone walls underwent marked surface resorption and (ii) the height of the thin buccal hard tissue wall was reduced. The process of healing continued, and the buccal bone crest shifted further in the apical direction. After 12 weeks, the buccal crest was located>2 mm apical of the marginal border of the SLA surface. Conclusion: The bone-to-implant contact that was established during the early phase of socket healing following implant installation was in part lost when the buccal bone wall underwent continued resorption. [source] Caries outcomes after orthodontic treatment with fixed appliances: do lingual brackets make a difference?EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 3 2010M. H. Van Der Veen van der Veen MH, Attin R, Schwestka-Polly R, Wiechmann D. Caries outcomes after orthodontic treatment with fixed appliances: do lingual brackets make a difference? Eur J Oral Sci 2010; 118: 298,303.©2010 The Authors. Journal compilation © 2010 Eur J Oral Sci Orthodontic treatment with fixed appliances is considered a risk factor for the development of white spot caries lesions (WSL). Traditionally, brackets are bonded to the buccal surfaces. Lingual brackets are developing rapidly and have become more readily available. Buccal surfaces are considered to be more caries prone than lingual surfaces. Furthermore, lingual brackets are shaped to fit the morphology of the teeth and seal almost the entire surface. In the present study we tested the hypothesis that lingual brackets result in a lower caries incidence than buccal brackets. We tested this hypothesis using a split-mouth design where subjects were allocated randomly to a group receiving either buccal or lingual brackets on the maxillary teeth and the alternative bracket type in the mandible. The results indicate that buccal surfaces are more prone to WSL development, especially when WSL existed before treatment. The number of WSL that developed or progressed on buccal surfaces was 4.8 times higher than the number of WSL that developed or progressed on lingual surfaces. When measured using quantitative light-induced fluorescence (QLF), the increase in integrated fluorescence loss was 10.6 times higher buccally than lingually. We conclude that lingual brackets make a difference when caries lesion incidence is concerned. [source] Enamel microhardness and bond strengths of self-etching primer adhesivesEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2010Olabisi A. Adebayo Adebayo OA, Burrow MF, Tyas MJ, Adams GG, Collins ML. Enamel microhardness and bond strengths of self-etching primer adhesives. Eur J Oral Sci 2010; 118: 191,196. © 2010 The Authors. Journal compilation © 2010 Eur J Oral Sci The aim of this study was to determine the relationship between enamel surface microhardness and microshear bond strength (,SBS). Buccal and lingual mid-coronal enamel sections were prepared from 22 permanent human molars and divided into two groups, each comprising the buccal and lingual enamel from 11 teeth, to analyze two self-etching primer adhesives (Clearfil SE Bond and Tokuyama Bond Force). One-half of each enamel surface was tested using the Vickers hardness test with 10 indentations at 1 N and a 15-s dwell time. A hybrid resin composite was bonded to the other half of the enamel surface with the adhesive system assigned to the group. After 24 h of water storage of specimens at 37º°C, the ,SBS test was carried out on a universal testing machine at a crosshead speed of 1 mm min,1 until bond failure occurred. The mean ,SBS was regressed on the mean Vickers hardness number (VHN) using a weighted regression analysis in order to explore the relationship between enamel hardness and ,SBS. The weights used were the inverse of the variance of the ,SBS means. Neither separate correlation analyses for each adhesive nor combined regression analyses showed a significant correlation between the VHN and the ,SBS. These results suggest that the ,SBS of the self-etch adhesive systems are not influenced by enamel surface microhardness. [source] Effect on de novo plaque formation of rinsing with toothpaste slurries and water solutions with a high fluoride concentration (5,000 ppm)EUROPEAN JOURNAL OF ORAL SCIENCES, Issue 5 2009A. Nordström The aim of this study was to evaluate the effect, on de novo plaque formation, of rinsing with toothpaste slurries and water solutions containing a high concentration of fluoride (F). Sixteen subjects rinsed three times per day for 4 d with dentifrice slurries containing 5,000, 1,500, and 500 ppm F, while 12 subjects rinsed with water solutions containing 5,000, 1,500, 500, and 0 ppm F, and 1.5% sodium lauryl sulphate (SLS). Plaque was scored [using the Quigley & Hein index (QHI)] after each 4-d period. Plaque samples for F analysis were collected. Significantly less plaque was scored for the dentifrice slurry containing 5,000 ppm F (buccal and all surfaces) and for 1.5% SLS (buccal surfaces). The differences in plaque scores between dentifrice containing 5,000 and 1,500 ppm F were 19% for all surfaces and 33% for buccal surfaces. The difference between the water solutions containing 1.5% SLS and 1,500 ppm F for buccal surfaces was 23%; the corresponding difference for 5,000 ppm F was 17%. The dentifrice slurry containing 5,000 ppm F accumulated 56% more F in plaque. The combination of high levels of F and SLS in dentifrice reduces de novo plaque formation and increases the accumulation of F in plaque after 4 d. [source] Haemostatic management of intraoral bleeding in patients with congenital deficiency of ,2-plasmin inhibitor or plasminogen activator inhibitor-1HAEMOPHILIA, Issue 5 2004Y. Morimoto Summary., Haemostatic management of intraoral bleeding was investigated in patients with congenital ,2-plasmin inhibitor (,2-PI) deficiency or congenital plasminogen activator inhibitor- 1 (PAI-1) deficiency. When extracting teeth from patients with congenital ,2-PI deficiency, we advocate that 7.5,10 mg kg,1 of tranexamic acid be administered orally every 6 h, starting 3 h before surgery and continuing for about 7 days. For the treatment of continuous bleeding, such as post-extraction bleeding, 20 mg kg,1 of tranexamic acid should be administered intravenously, and after achieving local haemostasis 7.5 mg kg,1 of tranexamic acid should be administered orally every 6 h for several days. In addition, when treating haematoma caused by labial or gingival laceration or buccal or mandibular contusion, haemostasis should be achieved by administering 7.5,10 mg kg,1 of tranexamic acid every 6 h. Tranexamic acid can also be used for haemostatic management of intraoral bleeding in patients with congenital PAI-1 deficiency, but is less effective when compared with use in patients with congenital ,2-PI deficiency. Continuous infusion of 1.5 mg kg,1 h,1 of tranexamic acid is necessary for impacted tooth extraction requiring gingival incision or removal of local bone. [source] Permeation of Sumatriptan Through Human Vaginal and Buccal MucosaHEADACHE, Issue 2 2000P. Van Der Bijl DSc Continued interest in the various routes by which sumatriptan may be administered prompted us to investigate its passage through buccal mucosa. Because human buccal mucosa is scarce, we proposed using the relatively abundant vaginal mucosa, which has been shown to have comparable diffusion rates for a number of widely varying molecules, as a model of buccal mucosa. In addition, by comparing these two tissues with respect to their permeability to sumatriptan, the human vaginal/buccal mucosa model could be further evaluated. Clinically healthy human vaginal and buccal mucosa specimens were used in the permeability studies. Permeability to sumatriptan was determined using a continuous flow-through diffusion system in the presence and absence of permeation enhancers. No statistically significant differences in permeability could be demonstrated for both mucosae toward sumatriptan. Flux values obtained in the absence and presence of glycodeoxycholate and lauric acid (1:1 molar ratio) to sumatriptan of buccal and vaginal mucosa, respectively, were not significantly different. The results obtained further support the hypothesis of the vaginal/buccal mucosal in vitro permeability model and suggest that this model may be used in conjunction with various absorption enhancers. Further studies on the buccal route of absorption of sumatriptan are thus warranted. [source] Thickness of dentine in mesial roots of mandibular molars with different lengthsINTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2010T. S. Sauáia Sauáia TS, Gomes BPFA, Pinheiro ET, Zaia AA, Ferraz CCR, Souza-Filho FJ, Valdrighi L. Thickness of dentine in mesial roots of mandibular molars with different lengths. International Endodontic Journal, 43, 555,559, 2010. Abstract Aim, To measure the minimum thickness of the distal (furcal) root dentine associated with the buccal and lingual canals of the mesial roots of mandibular first molars with different lengths. Methodology, The mesial roots of 285 mandibular first molars were allocated into three groups according to their length: group I , long (24.14 mm ± 0.85), group II , medium (22.10 mm ± 0.65) and group III , short (19.97 mm ± 0.75). The minimum thickness of the distal (furcal) root dentine associated with the buccal and lingual canals of the mesial roots 2 mm below the furcation was measured. The distance between the buccal and lingual canals, and the depth of concavity in the distal surface of the mesial roots were also measured. anova and Tukey,Kramer were used to test for significant differences among the groups. Results, The minimum thickness of the distal wall of the mesiobuccal canal was significantly different (P < 0.05) between group I (long) and III (short), with long teeth having the smallest mean values. No significant difference was found in the thickness of the distal wall of the mesiolingual canal among the groups studied (P > 0.05). The shortest distance between the mesiobuccal and the mesiolingual canals was observed in group III (P < 0.05). The distal (furcal) concavity was deeper in group I (P < 0.05) when compared with the other groups. Conclusion, There was a significant difference in the minimum thickness of the distal (furcal) root wall of the mesiobuccal canal of mandibular first molars 2 mm below the furcation between group I (long) and group III (short) teeth. The thinnest walls were found in the longest teeth. The deepest concavities in the distal (furcal) walls of the mesial roots were found in the longest roots. [source] Influence of endodontic treatment, post insertion, and ceramic restoration on the fracture resistance of maxillary premolarsINTERNATIONAL ENDODONTIC JOURNAL, Issue 6 2010K. Bitter Bitter K, Meyer-Lueckel H, Fotiadis N, Blunck U, Neumann K, Kielbassa AM, Paris S. Influence of endodontic treatment, post insertion, and ceramic restoration on the fracture resistance of maxillary premolars. International Endodontic Journal, 43, 469,477, 2010. Abstract Aim, To investigate the effects of endodontic treatment, post placement and ceramic restoration type on the fracture resistance of premolars. Methodology, One hundred and twenty teeth maxillary premolars were allocated to four groups (A,D; n = 30). In group A, mesio-occlusal-distal-inlays with a buccal and palatal wall of 2 mm (MOD), in group B partial onlays with palatal cusp coverage and in group C total onlays with buccal and palatal cusp coverage were prepared. Group D served as untreated controls. Groups A,C were divided into three subgroups (n = 10): (i) teeth received solely the described preparations, (ii) teeth were root filled, (iii) teeth were root filled and quartz fibre posts were placed. Teeth were restored using Computer-assisted design/computer-assisted machining-ceramic-restorations and subjected to thermo-mechanical-loading; subsequently, the buccal cusp was loaded until fracture. Results, Group D revealed significantly higher fracture resistance [mean (standard deviation)] [738 (272) N] compared to all other groups (P < 0.05; post hoc test Dunnett). For groups A,C, fracture resistance was significantly affected by the restoration type (P = 0.043) and endodontic treatment/post placement (P = 0.039; 2-way anova). Group A [380 (146) N] showed significantly lower fracture resistance compared to group B [470 (158) N] (P = 0.048; post hoc test Tukey). Compared to non-endodontically treated teeth [487 (120) N], root filled teeth revealed significantly lower fracture resistance [389 (171) N] (P = 0.031). Conclusion, The restoration of cavities with a remaining wall thickness of 2 mm using ceramic MOD-inlays is inferior with respect to the fracture resistance compared to partial onlay restorations. Root filled teeth without post placement show lower fracture resistance compared to non-endodontically treated teeth. [source] Dentine removal in the coronal portion of root canals following two preparation techniquesINTERNATIONAL ENDODONTIC JOURNAL, Issue 11 2007G. Plotino Abstract Aim, To measure the root canal area and the reduction of the mesial and buccal/lingual wall thickness at the level of the coronal interference in mesial roots of mandibular molars after instrumentation with a crown-down or a simultaneous root canal preparation technique. Methodology, Twenty mesial roots of first mandibular molars with a moderate root canal curvature were embedded in resin and sectioned horizontally at the level of the coronal interference, using a modification of the Bramante technique. After scanning and processing, the sections were reassembled. One root canal of each root was prepared using ProTaper instruments, while Mtwo instruments were used in the other root canal of the same mesial root. After scanning and processing, the data obtained were analysed for two parameters: changes in root canal area after instrumentation (,A) and reduction of the mesial and buccal/lingual wall thickness (,T). The data were subjected to Student's t -tests for statistical analysis at a significance level of P < 0.05. Results, No statistically significant differences were found between the two groups with respect to the changes in the areas (,A) at the level considered (P = 0.410). No statistically significant differences were noticed between the two groups for dentine thickness (,T) of both the mesial wall (P = 0.077) and the buccal or lingual wall (P = 0.171). Conclusions, There was no difference between the ProTaper and Mtwo groups for the amount of dentine removed. [source] Changes in compaction stress distributions in roots resulting from canal preparationINTERNATIONAL ENDODONTIC JOURNAL, Issue 12 2006A. Versluis Abstract Aim, To examine if canal enlargement with instruments of controlled taper leads to more uniform stress distributions within a root, thereby reducing fracture susceptibility. Methodology, Finite element models of a mandibular incisor were constructed with round and oval canal profiles, based on measurements from extracted teeth. The shapes of rotary nickel,titanium instruments (ProTaper F1, F2, and F3 and ProFile size 30, 0.04 taper and size 30, 0.06 taper; Dentsply Maillefer) were superimposed on the canals. Equivalent stresses and circumferential stresses in the root were calculated for a compaction load. Results, The highest stresses were found at the canal wall. Round canals showed lower uniform distributions, whilst oval canals showed uneven distributions with high concentrations at the buccal and lingual canal extensions and greater stresses in the coronal and middle thirds than in the apical third. Preparation of round canals introduced only small circumferential stress increases in the apical half; preparation of oval canals produced substantial reductions where the canal was enlarged to a smooth round shape. Even where fins were not completely eliminated, the maximum stresses were still reduced by up to 15%. External distal and mesial surfaces of roots with oval canals showed moderate stress concentrations that were minimally affected by preparations, whilst stress concentrations emerged on roots with round canals when preparation sizes increased. Conclusions, The potential for reducing fracture susceptibility exists as a result of round canal profiles achieved and smooth canal taper. Even when fins were not contacted by the instrument, stresses within the root were lower and more evenly distributed than before preparation. [source] Evaluation of canal filling after using two warm vertical gutta-percha compaction techniques in vivo: a preliminary studyINTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2006M. Venturi Abstract Aim, To evaluate the quality of root canal filling when comparing two warm gutta-percha filling techniques in vivo. Methodology, Human teeth were randomly divided into two equal groups, with 30 canals each. The root canals were shaped by hand and ProFile 0.04 rotary instruments to size 20,40 at the end-point and then filled with gutta-percha cones and AH-Plus. In group A, a traditional warm vertical compaction technique was performed using the Touch'n Heat, and back-filling with the Obtura II. In group B, a modified warm vertical compaction technique was used: small amounts of gutta-percha were removed, and the remaining most apical 3 mm were compacted with a 1 mm movement; then thermomechanical back-filling was performed. The teeth were extracted, stored in dye, cleared, and the distance between the apex and apical limit of the filling, linear dye penetration, and voids were measured from the buccal, lingual, mesial and distal perspective. The homogeneity of variance and means was verified using Levene's test and t -test. anova and Dunnett post hoc test were used to establish the significance and to analyse the effects through multiple comparisons. Results, Compared with the specimens of group A, the specimens of group B exhibited less mean linear dye penetration (P < 0.05), smaller void length (P , 0.05) and maximal width (P , 0.05) when examined in all four views, and a more precise filling when viewed from the buccal aspect (P < 0.05). Conclusions, The modified warm vertical compaction technique with apical back-filling produced a more effective and precise three-dimensional filling. [source] Effect of access cavity location and design on degree and distribution of instrumented root canal surface in maxillary anterior teethINTERNATIONAL ENDODONTIC JOURNAL, Issue 3 2001G. Mannan Abstract Aim The null hypothesis tested in this study was that in single-rooted anterior teeth with simple root canal anatomy, different access cavity designs (,lingual cingulum', ,lingual conventional', ,incisal straight-line') do not influence the ability of endodontic files to plane the walls of the root canals. Methodology, Thirty extracted human maxillary anterior teeth were divided randomly into three groups for each access cavity. The access cavities were prepared according to predefined criteria and the roots embedded in individual polyvinyl-siloxane putty matrices. The matrices allowed these teeth to be split into buccal and palatal halves and to be reassembled. The split teeth enabled removal of pulpal remnants from the root canal system and the walls to be stained with an even layer of permanent black ink. Once dried, the split roots were reassembled in the putty matrices and a step-back filing technique was used to prepare the canals with water irrigation. The canal walls were examined for residual ink staining and scored by three independent assessors using an index devised for the purpose. Results There was good agreement between the assessors. None of the access cavities allowed file contact with the entire root canal wall. The overall (palatal and buccal sections) scores showed significant differences (P < 0.01) between the access cavity groups in the extent to which the canal walls could be filed. The straight-line incisal access cavity had the greatest proportion of instrumented root canal surface. The lingual cingulum access cavity was the worst in this respect. The differences in residual ink scores between the access cavity types were significant for the buccal halves (P < 0.01) but not for the palatal halves (P > 0.05). Conclusions The null hypothesis was proven. Regardless of access cavity design, mechanical preparation did not allow instrumentation of the entire root canal wall. Straight-line access allowed the greatest proportion of the root canal wall to be instrumented and the lingual cingulum access the least. [source] Oropharyngeal Skeletal Disease Accompanying High Bone Mass and Novel LRP5 Mutation,,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 5 2005Michael R Rickels Abstract Gain-of-function mutation in the gene encoding LRP5 causes high bone mass. A 59-year-old woman carrying a novel LRP5 missense mutation, Arg154Met, manifested skeletal disease affecting her oropharynx as well as dense bones, showing that exuberant LRP5 effects are not always benign. Introduction: Gain-of-function mutation (Gly171Val) of LDL receptor-related protein 5 (LRP5) was discovered in 2002 in two American kindreds with high bone mass and benign phenotypes. In 2003, however, skeletal disease was reported for individuals from the Americas and Europe carrying any of six novel LRP5 missense mutations affecting the same LRP5 protein domain. Furthermore, in 2004, we described a patient with neurologic complications from dense bones and extensive oropharyngeal exostoses caused by the Gly171Val defect. Materials and Methods: A 59-year-old woman was referred for dense bones. Three years before, mandibular buccal and lingual exostoses (osseous "tori") were removed because of infections from food trapping between the teeth and exostoses. Maxillary buccal and palatal exostoses were asymptomatic. Radiographic skeletal survey showed marked thickening of the skull base and diaphyses of long bones (endosteal hyperostosis). BMD Z scores assessed by DXA were +8.5 and +8.7 in the total hip and L1 -L4 spine (both ,195% average control), respectively. LRP5 mutation analysis was carried out for the LRP5 domain known to cause high bone mass. Results: Biochemical evaluation excluded most secondary causes of dense bones, and male-to-male transmission in her family indicated autosomal dominant inheritance. PCR amplification and sequencing of LRP5 exons 2-4 and adjacent splice sites revealed heterozygosity for a new LRP5 missense mutation, Arg154Met. Conclusions: LRP5 Arg154Met is a novel defect that changes the same first ",-propeller" module as the eight previously reported LRP5 gain-of-function missense mutations. Arg154Met alters a region important for LRP5 antagonism by dickkopf (Dkk). Therefore, our patient's extensive oropharyngeal exostoses and endosteal hyperostosis likely reflect increased Wnt signaling and show that exuberant LRP5 effects are not always benign. [source] Stability of crestal bone level at platform-switched non-submerged titanium implants: a histomorphometrical study in dogsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2009Jürgen Becker Abstract Objectives: To investigate the influence of platform switching on crestal bone level changes at non-submerged titanium implants over a period of 6 months. Material and Methods: Titanium implants (n=72) were placed at 0.4 mm above the alveolar crest in the lower jaws of 12 dogs and randomly assigned to either matching or non-matching (circumferential horizontal mismatch of 0.3 mm) healing abutments. At 4, 8, 12, and 24 weeks, dissected blocks were processed for histomorphometrical analysis. Measurements were made between the implant shoulder (IS) and the apical extension of the long junctional epithelium (aJE), the most coronal level of bone in contact with the implant (CLB), and the level of the alveolar bone crest (BC). Results: At 24 weeks, differences in the mean IS,aJE, IS,CLB, and IS,BC values were 0.2 ± 1.2, 0.3 ± 0.7, and 0.3 ± 0.8 mm at the buccal aspect, and 0.2 ± 0.9, 0.3 ± 0.5, and 0.3 ± 0.8 mm at the lingual aspect, respectively. Comparisons between groups revealed no significant differences at either the buccal or the lingual aspects. Conclusions: It was concluded that (i) bone remodelling was minimal in both groups and (ii) platform switching may not be of crucial importance for maintenance of the crestal bone level. [source] Gingival blood flow changes following periodontal access flap surgery using laser Doppler flowmetryJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 5 2007M. Retzepi Abstract Aim: To investigate the pattern of gingival blood flow changes following periodontal access flap surgery by laser Doppler flowmetry (LDF). Material and methods: Fourteen patients with chronic periodontitis presenting upper anterior sites with pocket depth 5 mm after initial treatment were included in the study. Periodontal access flap surgery was performed on the experimental areas and LDF recordings were taken at baseline, following anaesthesia, immediately postoperatively and on days 1, 2, 3, 4, 7, 15, 30 and 60 of healing, at nine predetermined sites per flap. Results: Significant ischaemia was observed at all flap sites following anaesthesia and immediately postoperatively. At the alveolar mucosal sites, a peak increase of the gingival blood flow was observed on postoperative day 1 (p<0.001), which persisted until day 7 (p=0.012) and resolved by day 15. The mucosal sites close to the flap periphery presented higher blood perfusion compared with the sites located centrally in the flap. The microcirculatory perfusion of the buccal and palatal papillae was maximum on postoperative day 7 (p=0.013 and <0.001, respectively) and returned to baseline by day 15. Conclusion: Topographically distinct areas of the periodontal access flap consistently present different patterns of microvascular blood flow alterations during the wound-healing period. [source] Labial piercing resulting in gingival recession.JOURNAL OF CLINICAL PERIODONTOLOGY, Issue 10 2002A case series Abstract Several complications of oral piercing have been recently reported in the medical and dental literature. Even though few people have had problems related to oral piercing, dentists should familiarise themselves with the potential associated oral and dental problems. We present three cases of young people with gingival recession in the mandibular incisor area related to labial piercing. The clinical examination and the dental history of the three cases revealed the relationship between the gingival recession and the presence of labial piercing. In particular, a stud in the lower lip was held in place by a metal disk on the inner labial mucosa in each case. The metal disk was in close proximity to the mandibular front teeth and it would appear that it was responsible for local trauma and recession. This case series reinforces previously reported concerns regarding the practice of piercing and the role of the dentist, both in advising patients with oral or facial piercing and in the treatment of related oral, gingival and dental problems. Zusammenfassung Durchstochene Lippen führten zu einer Retraktion Gingiva. Eine Fallserie In jüngerer Zeit wurden in der allgemein- und zahnmedizinischen Literatur eine Reihe von Komplikationen nach Durchstechen des Mundgewebes berichtet. Obwohl nur wenige Menschen Probleme nach durchstochenen Lippen bekamen, sollten sich Zahnärzte dennoch mit den potentiell mit dieser Praxis verbundenen Zahnproblemen beschäftigen. Wir stellen hier drei Fälle von jungen Menschen mit einer Retraktion der Gingiva im Bereich der mandibulären Schneidezähne vor, die auf ein Durchstechen der Lippen zurückzuführen ist. Die klinische Untersuchung und die Zahnanamnese der drei Fälle zeigte eine Verbindung zwischen der Retraktion der Gingiva und den durchstochenen Lippen. In jedem der Fälle wurde ein Stecker in der Unterlippe durch eine an der inneren Schleimhaut der Unterlippe anliegende Metallscheibe festgehalten. Die Metallscheibe lag in der direkten Umgebung der mandibulären Schneidezähne und wir gehen davon aus, das diese Scheibe für das lokale Trauma und die Retraktion der Gingiva verantwortlich war. Diese Fallserie unterstützt an früherer Stelle ausgedrückte Besorgnisse in Bezug auf das Durchstechen der Lippen und die Rolle des Zahnarztes, sowohl bei der Beratung des Patienten in Bezug auf das Durchstechen der Lippen bzw. anderer Gesichtsteile, als auch bei der Behandlung damit verbundener oraler, gingivaler oder dentaler Probleme. Résumé Piercing labial entraînant une récession gingivale. Série de cas La littérature médicale et dentaire a récemment fait état de plusieurs complications dues au piercing buccal. Bien que peu de personnes aient eu des problèmes liés au piercing buccal, les dentistes devraient se familiariser avec les potentielles complications buccales et dentaires qui lui sont associées. Nous exposons les cas de trois jeunes personnes présentant une récession gingivale dans la région incisive mandibulaire, en relation avec un piercing labial. L'examen clinique et le passé dentaire des trois cas ont mis en évidence la relation entre la récession gingivale et la présence d'un piercing labial. En particulier, dans chaque cas, un clou placé dans la lèvre inférieure était maintenu en place par un disque métallique situé sur la muqueuse labiale interne. Ce disque était à proximité des dents mandibulaires antérieures, et il semblerait qu'il ait étéà l'origine d'un traumatisme local et d'une récession. Cette série de cas renforce les préoccupations déjàévoquées dans le passé sur la pratique du piercing, ainsi que sur le rôle du dentiste, à la fois pour conseiller les patients sur le piercing buccal et facial et pour traiter les problèmes dentaires buccaux et gingivaux associés. [source] A controlled re-entry study on the effectiveness of bovine porous bone mineral used in combination with a collagen membrane of porcine origin in the treatment of intrabony defects in humansJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 12 2000Paulo M. Camargo Abstract Aim: The purpose of this study was to evaluate the clinical effectiveness of a bovine porous bone mineral used in combination with a porcine derived collagen membrane as a barrier in promoting periodontal regeneration in intrabony defects in humans. Material and Methods: The study employed a split-mouth design. 22 paired intrabony defects were treated and surgically re-entered 6 months after treatment. Experimental sites were grafted with bovine porous bone mineral and received a collagen membrane for guided tissue regeneration. Control sites were treated with an open flap debridement. Results: Preoperative pocket depths, attachment levels and trans-operative bone measurements were similar for control and experimental sites. Post surgical measurements revealed a significantly greater reduction in pocket depth (differences of 1.89±0.31 mm on buccal 0.88±0.27 mm on lingual measurements) and more gain in clinical attachment (differences of 1.51±0.33 mm on buccal and 1.50±0.35 mm on lingual measurements) in experimental sites. Surgical reentry of the treated defects revealed a significantly greater amount of defect fill in favor of experimental sites (differences of 2.67±0.91 mm on buccal and 2.54±0.87 mm on lingual measurements). Conclusions: The results of this study indicate that clinical resolution of intrabony defects can be achieved using a combination of bovine porous bone mineral and an absorbable, porcine derived collagen membrane when employing a technique based on the principles of guided tissue regeneration. The nature of the attachment between the newly regenerated tissue and the root surfaces needs to be evaluated histologically to confirm the presence of new attachment. [source] Scanning Electron Microscope Analysis of Internal Adaptation of Materials Used for Pulp Protection under Composite Resin RestorationsJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 2 2005MARIA INEZ LEMOS PELIZ DDS ABSTRACT Purpose:: The aim of this study was to evaluate the interfacial microgap with different materials used for pulp protection. The null hypothesis tested was that the combination of calcium hydroxide, resin-modified glass ionomer, and dentin adhesive used as pulp protection in composite restorations would not result in a greater axial gap than that obtained with hybridization only. Materials and Methods: Standardized Class V preparations were performed in buccal and lingual surfaces of 60 caries-free, extracted human third molars. The prepared teeth were randomly assessed in six groups: (1) Single Bond (SB) (3M ESPE, St. Paul, MN, USA); (2) Life (LF) (Kerr Co., Romulus, MI, USA) + SB; (3) LF + Vitrebond (VT) (3M ESPE) + SB; (4) VT + SB; (5) SB + VT; (6) SB + VT + SB. They were restored with microhybrid composite resin Filtek Z250 (3M ESPE), according to the manufacturer's instructions. However, to groups 5 and 6, the dentin bonding adhesive was applied prior to the resin-modified glass ionomer. The specimens were then thermo-cycled, cross-sectioned through the center of the restoration, fixed, and processed for scanning electron microscopy. The specimens were mounted on stubs and sputter coated. The internal adaptation of the materials to the axial wall was analyzed under SEM with × 1,000 magnification. Results: The data obtained were analyzed with nonparametric tests (Kruskal-Wallis, p V .05). The null hypothesis was rejected. Calcium hydroxide and resin-modified glass ionomer applied alone or in conjunction with each other (p < .001) resulted in statistically wider microgaps than occurred when the dentin was only hybridized prior to the restoration. [source] Immunohistochemical expression of RANKL, RANK, and OPG in human oral squamous cell carcinomaJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 10 2009Fu-Hsiung Chuang Background:, The mechanism of oral squamous cell carcinoma (SCC) invading jawbone remains controversial. Interactions between receptor activator of NF-,B (RANK) and its ligand (RANKL) are required for osteoclastogenesis. The binding of RANK and RANKL induces differentiation of osteoclasts, leading to bony destruction. Osteoprotegerin (OPG), a decoy receptor for RANKL, also binds to RANKL by competing with RANK, and this could protect against osseous destruction. Materials and methods:, Immunoexpression of RANKL, RANK, and OPG in 25 cases of human buccal SCCs without bony invasion and 15 cases of gingival SCCs with mandibular bony invasion was investigated. Normal oral mucosa from five individuals without betel-quid chewing or cigarette smoking was used as a control. The scores are designated as percentage of positive staining × intensity of staining for each section. Results:, Strong cytoplasmic staining of RANKL proteins is detected in cancer cells of both buccal and gingival SCCs. The same protein is identified in cytoplasm of osteoclasts for all cases involving bony invasion. Strong cytoplasmic staining of RANKL is confined to basal layer for all normal mucosa. A similar staining pattern is noted for RANK protein in all buccal and gingival SCCs. An absence of staining of RANK protein is noted for all normal tissues. Weak to negative cytoplasmic stained OPG protein is present in all buccal and gingival SCCs, but is absent in all normal tissues. Conclusion:, These findings suggest the potential value of the RANK/RANKL/OPG pathway as biomarkers in human oral SCCs. [source] Diffusion of reduced arecoline and arecaidine through human vaginal and buccal mucosaJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 4 2001P. Van der Bijl Abstract: Because alkaloids from areca nut, arecoline and arecaidine, have been implicated in the development of oral submucous fibrosis, we determined their diffusion kinetics through human buccal and vaginal mucosa. Four clinically healthy vaginal mucosa specimens (mean patient age± standard deviation: 47±15 years; age range: 31,60 years) and 4 buccal mucosa specimens from 2 male patients and 2 female patients (mean patient age±standard deviation: 31±9 years; age range: 17,53 years) were obtained during surgery. In vitro flux rates of reduced arecoline and arecaidine (r-arecoline and r-arecaidine) were determined by use of a flow-through diffusion apparatus. Analysis of variance, a Duncan multiple range test, and an unpaired t -test were used to determine steady state kinetics and flux differences over time intervals. Although statistically significant differences were observed between flux values for both alkaloids and tissues at certain time points, these were not considered to be of biological (clinical) significance. However, the flux rates across both mucosa of r-arecoline were significantly higher statistically than those of r-arecaidine. The findings demonstrated the differences in the diffusion kinetics between r-arecoline and r-arecaidine across human buccal and vaginal mucosa, an observation that could be explained in terms of their ionisation characteristics. Additionally, the results obtained further support the hypothesis that human vaginal mucosa can be used as a model for buccal mucosa in studies of permeability to various chemical compounds. [source] Facial and glossal distribution of anaesthesia after inferior alveolar nerve blockJOURNAL OF ORAL REHABILITATION, Issue 2 2003H.-K. Kim summary, The aim of this study was to subjectively determine the distribution of anaesthesia by mapping areas of sensory loss following inferior alveolar nerve block. Fifty healthy dental students were the subjects of this study (men 32, women 18). They were asked to draw the anaesthetized area on a diagram of the face and tongue 20 min after inferior alveolar nerve block. They evaluated the degree of anaesthesia by touching their faces and moving their tongues. All of the 50 subjects reported anaesthesia in the facial area. Of these, 21 (42%) reported the cutaneous distribution of anaesthesia on mental nerve territory only. Seventeen subjects (34%) reported anaesthesia on mental and buccal nerve territory. Nine subjects (18%) reported anaesthesia on mental, buccal, and auriculotemporal nerve territory. Two subjects (4%) reported anaesthesia on mental and auriculotemporal nerve territory and one subject (2%) on mental, buccal and infra-orbital nerve territory. Forty-seven of the 50 subjects (94%) reported anaesthesia of the tongue with the various degree of anaesthesia according to the area. Of these, 17 subjects (34%) reported strong anaesthesia on the anterior area and weak anaesthesia on the middle part of the tongue. Nineteen subjects (38%) reported strong anaesthesia of the lateral area and weak anaesthesia on the medial area, and 11 subjects (22%) reported anaesthesia on only the lateral side of the tongue. Three subjects (6%) reported no anaesthesia of the tongue. The distribution of anaesthesia of the facial and glossal regions determined subjectively after inferior alveolar nerve block, varies significantly between individuals. [source] Buccal and lingual activity during mastication and swallowing in typical adultsJOURNAL OF ORAL REHABILITATION, Issue 1 2003M. J. Casas summary, A non-invasive protocol was developed to assess tongue and cheek movements during mastication and to evaluate the temporal relationship between mastication and the initiation of pharyngeal swallowing. Typical adults (three males and three females) were monitored during chewing. Miniature pressure transducers were bonded unilaterally to the buccal and lingual surfaces of the first mandibular molar and the buccal surface of the first maxillary molar on each subject's preferred chewing side. Surface electromyography of the ipsilateral masseter muscle was recorded as an indicator of jaw-closing activity. Pressure and electromyography (EMG) recordings were time-linked to simultaneous B-mode ultrasound imaging of the oral cavity using a submental, coronal view aligned with the first mandibular molar. The intervals between peak pressure recorded at each pressure transducer and peak jaw-closing activity for each masticatory cycle were not statistically different [analysis of variance (anova), P=0·9856] and displayed large statistical variation. These intervals were not different at the beginning of the trials (hard biscuit) than they were at the completion of mastication when the cookie had been broken down to a paste/puree consistency bolus. The interval between the last chewing stroke and the initiation of swallowing was 0·92 ± 0·34 s). No significant difference existed among subjects for this time interval (anova, P=0·382). [source] Pressure,pain threshold determination in the oral mucosa: validity and reliabilityJOURNAL OF ORAL REHABILITATION, Issue 7 2002T. Ogimoto Fundamental knowledge of pain in the oral mucosa is lacking. We determined the validity and reliability of the pressure,pain threshold (PPT) measurement in the oral mucosa using a newly developed hand-held pressure algometer. Ten dentulous subjects were recruited, and the PPT was measured at the bilateral buccal (on the attached gingiva apical to the midline of the upper first premolars, 3 mm from the mucogingival junction) and the palatal sites (mid-point between the bilateral upper first molars). The PPT linearly increased with an increase in load-rate (P < 0·0001). The PPT yielded a high intra-individual stability both for the same-day consecutive trials and weekly sessions. The palatal site revealed a 4- to 4·65-fold greater PPT than the buccal sites (Bonferroni, P < 0·0001), whereas no difference was found between the bilateral buccal sites (P=0·663). Despite a great interindividual variation in the PPT, significant intra-individual correlations were found among the measurement sites. This suggested differences in individual sensitivity to pain in the oral mucosa, which may determine overall pain sensation specific to an individual. A pressure algometer described herein reliably assessed the PPT in the oral mucosa and sensitively discriminated PPT differences at different sites and at different load-rates, suggest-ing the reliability and validity of PPT measure-ments in the oral mucosa for clinical and research investigations. [source] A biomechanical effect of wide implant placement and offset placement of three implants in the posterior partially edentulous regionJOURNAL OF ORAL REHABILITATION, Issue 1 2000Y. Sato To prevent loosening or fracture of screws retaining the prosthesis to the implants in the posterior partially edentulous region, the use of staggered buccal and lingual offset placement or wide implants is suggested. However, it is not known how this usage compensates for the torque produced by lateral occlusal forces. This study evaluated the effectiveness of offset placement of three implants and a wide implant placement at the most posterior site. Three-dimensional geometric analysis was used to calculate the tensile force applied to gold screws in clinical situations with buccal or lingual loading perpendicular to cuspal inclination (10 or 20°). Four variations of the placement of three implants (, 3·75 mm) are: (1) straight; (2) buccal offset of the second implant; (3) lingual offset of the second implant; (4) a wide implant (, 5 mm) placement at most posterior site. The offset placement did not always decrease tensile force at the gold screw, but wide implant placement and decrease in cuspal inclination did. [source] Polymeric enhancers of mucosal epithelia permeability: Synthesis, transepithelial penetration-enhancing properties, mechanism of action, safety issuesJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2008Giacomo Di Colo Abstract Transmucosal drug administration across nasal, buccal, and ocular mucosae is noninvasive, eliminates hepatic first-pass metabolism and harsh environmental conditions, allows rapid onset, and further, mucosal surfaces are readily accessible. Generally, however, hydrophilic drugs, such as peptides and proteins, are poorly permeable across the epithelium, which results in insufficient bioavailability. Therefore, reversible modifications of epithelial barrier structure by permeation enhancers are required. Low molecular weight enhancers generally have physicochemical characteristics favoring their own absorption, whereas polymeric enhancers are not absorbed, and this minimizes the risk of systemic toxicity. The above considerations have warranted the present survey of the studies on polymeric transmucosal penetration-enhancers that have appeared in the literature during the last decade. Studies on intestinal permeation enhancers are also reviewed as they give information on the mechanism of action and safety of polymers. The synthesis and characterization of polymers, their effectiveness in enhancing the absorption of different drugs across different epithelium types, their mechanism of action and structure-efficacy relationship, and the relevant safety issues are reviewed. The active polymers are classified into: polycations (chitosan and its quaternary ammonium derivatives, poly- L -arginine (poly- L -Arg), aminated gelatin), polyanions (N-carboxymethyl chitosan, poly(acrylic acid)), and thiolated polymers (carboxymethyl cellulose-cysteine, polycarbophil (PCP)-cysteine, chitosan-thiobutylamidine, chitosan-thioglycolic acid, chitosan-glutathione conjugates). © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97: 1652,1680, 2008 [source] Pharmaceutical applications of mucoadhesion for the non-oral routesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 1 2005Katarina Edsman The adhesion of pharmaceutical formulations to the mucosal tissue offers the possibility of creating an intimate and prolonged contact at the site of administration. This prolonged residence time can result in enhanced absorption and, in combination with a controlled release of the drug, also improved patient compliance by reducing the frequency of administration. During the almost 30 years over which mucoadhesion has been studied, a considerable amount of knowledge has been gained, and much has been learned about the different mechanisms occurring at the formulation-mucus interface and the properties that affect these mechanisms. The in-vivo performance of a dosage form not only depends on the mechanisms occurring at the interface, but also on the properties of the total mucoadhesive complex: the dosage form, the mucosa and the interface between them. A wide variety of methods are used for studying mucoadhesion; some rather similar to the in-vivo situation and some mimicking the interface alone. In this review, the mucus surface, the methods used for the study of mucoadhesion, the different mechanisms involved in mucoadhesion and theories underpinning them have been described. The complexity of mucoadhesion when trying to systemize the subject will also be discussed. The last part of the review describes the buccal, nasal, ocular, vaginal and rectal routes and provides examples of what can be achieved in-vivo when using mucoadhesive formulations. [source] | ||||||||||||||||||||||||||||||||||