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Occlusal Loading (occlusal + loading)
Selected AbstractsThe effect of irrigation time, root morphology and dentine thickness on tooth surface strain when using 5% sodium hypochlorite and 17% EDTAINTERNATIONAL ENDODONTIC JOURNAL, Issue 3 2010O. E. Sobhani Sobhani OE, Gulabivala K, Knowles JC, Ng Y-L. The effect of irrigation time, root morphology and dentine thickness on tooth surface strain when using 5% sodium hypochlorite and 17% EDTA. International Endodontic Journal, 43, 190,199, 2010. Abstract Aim, To evaluate the effect of irrigation with 5% sodium hypochlorite (NaOCl) alone and in conjunction with 17% ethylenediaminetetraacetic acid (EDTA) on tooth surface strain (TSS) and to analyse the influence of irrigation time, root morphology and dentine thickness. Methodology, Thirty-six single-rooted pre-molars with single canals had their crown and enamel reduced and root canals prepared using a standardized protocol. Teeth were grouped according to anatomical criteria and randomly distributed to experimental irrigation groups: (A) saline (negative control); (B) 5% NaOCl (positive control); (C) 5% NaOCl alternated with 17% EDTA. TSS was measured using electrical strain gauges bonded to the cervico-proximal part of the tooth. Teeth, mounted in clear acrylic resin placed in a universal testing machine, were subjected to nine consecutive 10-min irrigation periods followed by non-destructive occlusal loading to record TSS. Statistical analysis was carried out using two-way hierarchical anova and post hoc multiple comparisons. Results, Two groups showed an increase in TSS from the baseline (initial 10-min irrigation with saline). Group A showed a negligible reduction of 1.2% (343,339 ,,), which was not statistically significant (P = 0.7). Group B showed a highly significant (P = 0.001) increase in TSS by 53.7% (178,253 ,,), and group C showed a significant (P = 0.02) increase in TSS by 17.4% (163,192 ,,). The rate of change in TSS was significantly different between test groups. The length of the tooth (P = 0.04) as well as the mesio-distal (P = 0.05) width had significant effects on TSS. Conclusions, Irrigation with 5% with or without 17% EDTA increased TSS. The increase was significantly greater with 5% NaOCl alone than with 5% NaOCl alternated with 17% EDTA in contrast to previous findings with longer duration of irrigant exposure. Tooth length and mesio-distal root width significantly contributed to the increase in TSS. [source] Abfraction Lesions: Myth or Reality?JOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 5 2003J.S. REES BDS ABSTRACT Loss of tooth substance in the cervical region is usually attributed to toothbrush abrasion, erosion, or a combination of both factors. Recently the role of occlusal loading has become increasingly prominent. It is suggested that high occlusal loads cause large cervical stress concentrations, resulting in a disruption of the bonds between the hydroxyapatite crystals and the eventual loss of cervical enamel. This process has been called noncarious cervical tooth loss or abfraction. This article reviews the available evidence to support the thesis that occlusal loading can contribute to the process of abfraction. It also reviews the potential interactions between occlusal loading and erosion that may contribute to abfraction lesion formation. CLINICAL SIGNIFICANCE It is important to recognize the potential role of occlusal loading in the loss of cervical tooth tissue so that management of the occlusion can be incorporated into a treatment plan for a patient with abfraction lesions. [source] Analysis of load transfer and stress distribution by splinted and unsplinted implant-supported fixed cemented restorationsJOURNAL OF ORAL REHABILITATION, Issue 9 2010J. NISSAN Summary, Controversy remains over the rehabilitation of implant-supported restorations regarding the need to splint adjacent implant-supported crowns. This study compared the effects of simulated occlusal loading of three implants restored with cemented crowns, splinted versus unsplinted. Three adjacent screw-shaped implants were passively inserted into three holes drilled in a photo-elastic model. Two combinations of cemented restorations were fabricated; three adjacent unsplinted and three adjacent splinted crowns. Strain gauges were connected to the implant necks and to the margins of the overlaying crowns. Fifteen axial static loads of 20-kg loadings were carried out right after each other via a custom-built loading apparatus. Strain gauges located on the implant neck supporting splinted restoration demonstrated significantly (P < 0·001) more strain (sum of strains = 3348·54 microstrain) compared with the single crowns (sum of strains = 988·57 microstrain). In contrast, significantly (P < 0·001) more strain was recorded on the strain gauges located on the restoration margins of the single crowns (sum of strains = 756·32 microstrain) when compared with splinted restorations (sum of strains = 186·12 microstrain). The concept of splinting adjacent implants to decrease loading of the supporting structures may require re-evaluation. The clinical relevance of these findings needs further investigation. [source] Effect of simulated resin-bonded fixed partial denture clinical conditions on resin cement mechanical propertiesJOURNAL OF ORAL REHABILITATION, Issue 8 2003M. P. Walker summary The purpose of this study was to determine changes in flexural properties of resin cement under simulated resin-bonded fixed partial denture (RBFPD) clinical conditions using aqueous ageing and cyclic loading. Panavia F flexural modulus and strength were measured by static loading to failure after 48-h and 60-day aqueous ageing at 37 °C with and without simulated cyclic occlusal loading. Panavia F sorption and solubility were also measured. Scanning electron microscopy (SEM) was used to characterize the morphology of the fractured surfaces. A two-factor anova (P , 0·05) indicated that cyclic loading produced a significant increase in the flexural modulus with no significant effect on the flexural strength. Conversely, aqueous ageing time produced a significant decrease in flexural strength with no effect on the flexural modulus. The SEM fracture analysis indicated that resin matrix fracture occurred in static-aqueous specimens; while in the aqueous-cycled specimens, resin matrix fracture occurred in addition to an increasing proportion of filler/resin interface fracture. Collectively, these outcomes suggest that initial degradation under simulated resin cement clinical function may be related to breakdown of the filler/resin interface bond, which could contribute to in vivo RBFPD resin cement cohesive failure. [source] Three-dimensional finite element analysis of the facial skeleton on simulated occlusal loadingJOURNAL OF ORAL REHABILITATION, Issue 7 2001Martin D. Gross Development of predictive models of occlusal loading of the facial skeleton will be of value for prosthetic design in oral rehabilitation. A 3-D finite element (FE) model of a human skull, based on CT scans, was constructed to analyse strain and stress distribution in the facial skeleton caused by simulated occlusal loading. Vertical loads were applied simulating loading of the full maxillary arch and unilateral single point occlusal loading of maxillary molar, pre-molar, canine and incisor sites. Strain and stress regimes from Von Mises (VM) failure criteria and extension and compression diagrams showed even distribution of strain following loading of the full maxillary arch throughout the facial elements. For individual points, the highest VM concentrations were consistently located on the facial aspect several mm above the loading site. Strain trajectories divided into a ,V-shaped' pattern, from the loading point into medial and lateral branches with higher VM values in the medial. As the same load was applied from the posterior to anterior region, VM values increased on all facial areas. Strain patterns were less symmetric and there was an increase in strain in the alveolar arch and around the rim of the nasal cavity. The overall picture of the facial skeleton is of a vertical plate enabling it to withstand occlusal stresses by in-plane loading and bending in its own plane. The most efficient distribution of load was on maxillary full arch loading with the most unfavourable strain concentrations occurring on loading in the anterior region. [source] Report of a Case Receiving Full-Arch Rehabilitation in Both Jaws Using Immediate Implant Loading Protocols: A 1-Year Resonance Frequency Analysis Follow-UpCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 1 2006Michael Portmann DDS ABSTRACT Background:, Immediate occlusal implant loading has been documented as a viable treatment option for various indications. However, documentations related to full-arch rehabilitation are usually limited to treatment of one jaw at a time, thereby leaving the opposing dentition unchanged. Furthermore, clinical documentation using traditional, well-accepted measuring techniques may not be adequate when it comes to short-term evaluation of the success or failure of implants subjected to immediate occlusal loading. Purpose:, The purpose of this case report is to (1) present an implant stability follow-up of a patient receiving an immediate, implant-supported full-arch rehabilitation in both jaws and (2) evaluate the patient's acceptance of this rehabilitation. Materials and Methods:, A 68-year-old patient scheduled for implant treatment was selected for an immediate implant loading protocol in both jaws. During two surgical events 3 weeks apart, eight maxillary and four mandibular Brĺnemark System® Mk IV TiUniteTM fixtures (Nobel Biocare AB, Göteborg, Sweden) were inserted and subsequently used to immediately support a cross-arch fixed prosthesis in the maxilla and a bar-retained overdenture in the mandible. Implant stability was recorded from the day of surgery periodically during a 1-year follow-up using resonance frequency analysis (RFA). Results:, At the 1-year follow-up, based on clinical, RFA, and radiographic evaluations, all implants and the reconstructions were classified as successful. All maxillary implants showed a decrease in the implant stability quotient (ISQ) value from the measurement at the time of surgery to the first follow-up, whereas two of four mandibular implants revealed an initial drop in stability. Irrespective of a specific ISQ level measured at implant surgery (ISQ range 53,74) and despite an initial decrease in stability, measurements recorded at the 12-month follow-up indicated similar stability levels for all maxillary implants (ISQ range 64,68) or the group of mandibular implants (ISQ range 72,75) but with a higher ISQ level for mandibular implants. Furthermore, the patient's acceptance of the immediate full-arch rehabilitation in both jaws was high. Conclusions:, The present case report demonstrates that a slightly staged approach for full-arch rehabilitation in both jaws using immediate implant loading protocols is a realistic treatment option. Furthermore, RFA follow-up indicates that immediately occlusally loaded implants placed in reduced bone quality and quantity are more prone to loose stability in the early healing period compared with implants placed in dense bone quality. [source] Immediate occlusal loading and tilted implants for the rehabilitation of the atrophic edentulous maxilla: 1-year interim results of a multicenter prospective studyCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2008Tiziano Testori Abstract Objectives: The aims of this prospective study were to assess the treatment outcome of immediately loaded full-arch fixed bridges anchored to both tilted and axially placed implants for the rehabilitation of fully edentulous maxillae and to compare the outcome of axial vs. tilted implants. Material and methods: Forty-one patients with edentulous maxillae were included in the study. Each patient received a full-arch fixed bridge supported by four axial implants and two distal tilted implants. Loading was applied within 48 h from surgery. Patients were scheduled for follow-up at 6 months, 1 year and annually up to 5 years. Radiographic evaluation of marginal bone-level change was performed at 1 year. Results: One patient died 4 months after surgery. Thirty patients were followed for a minimum of 1 year (range 3,42 months, mean 22.1 months). Three failures were recorded at 1-year follow-up (two axial implants and one tilted). Two more implants (one tilted and one axially placed) were lost within 18 months of loading. The 1-year implant survival rate was 98.8% for both axial and tilted implants. Prosthesis success rate was 100% at 1 year. Marginal bone loss around axial and tilted implants at 12-month evaluation was similar, being, respectively, 0.9±0.4 (standard deviation) mm and 0.8±0.5 mm. Conclusions: The present preliminary data suggest that immediate loading associated with tilted implants could be considered to be a viable treatment modality for the atrophic maxilla and that there does not seem to be a different clinical outcome between tilted and axial implants. [source] Immediate occlusal loading of Osseotite implants in the lower edentulous jawCLINICAL ORAL IMPLANTS RESEARCH, Issue 3 2004A multicenter prospective study Abstract Objective: This paper reports the results of a prospective multicenter clinical study on immediately fully occlusally loaded full-arch screw-retained prostheses with distal extensions (hybrid prostheses) supported by Osseotite implants inserted in edentulous lower jaws. Method and material: Sixty-two patients were enrolled in four clinical centers. Three hundred and twenty-five Osseotite implants were inserted and occlusally loaded according to an immediate loading protocol. The temporary prosthesis was delivered 4 h from surgery. The final prosthesis was delivered after 6 months. Marginal bone loss was monitored from periapical radiographs using a computerized technique. Results: Two implants failed to integrate within 2 months of occlusal loading. A cumulative implant success rate of 99.4% was achieved for a period of 12,60 months postplacement (mean 28.6±14.1 (SD) months). Crestal bone loss around the immediately loaded implants was similar to that reported for standard delayed loading protocols. Conclusion: The results of this study suggest that the rehabilitation of the edentulous mandible by an immediate occlusally loaded hybrid prosthesis supported by five to six Osseotite implants represents a viable alternative treatment to classic delayed loading protocols. Résumé Cette étude rapporte les résultats d'une étude clinique multicentrique prospective sur la charge occlusale complčte immédiate de l'ensemble de la mâchoire sur des prothčses retenues par des implants-vis avec une extension distale supportée par des implants Osséotite insérés dans la mandibule de patients édentés. Soixante-deux patients ont été inclus dans quatre centres cliniques et 325 implants Osséotite ont été insérés et mis en charge occlusale suivant le protocole de charge immédiate. La prothčse temporaire était placée quatre heures aprčs la chirurgie. La prothčse finale était placée aprčs six mois. La perte osseuse marginale était enregistrée ŕ partir de radiographies périapicales via l'utilisation d'une technique informatisée. Deux implants ne se sont pas intégrés dans les deux mois de la mise en charge occlusale. Un taux de succčs cumulatif des implants de 99,4% a été atteint pendant une période de douze ŕ soixante mois aprčs le placement (moyenne 28±14,1 mois). La perte osseuse crestale autour des implants mis en charge immédiatement était semblable ŕ celle rapportée pour les protocoles de mise en charge retardée. Les résultats de cette étude suggčrent que la réhabilitation de la mandibule chez l'édenté par des prothčses placées sur des implants immédiatement mis en charge placées sur cinq ou six implants Osséotite représente un traitement alternatif au protocole classique avec une mise en charge retardée. Zusammenfassung Ziele: Diese Arbeit präsentiert die Daten einer longitudinalen klinischen Multizenterstudie über sofort mit Kaukräften belastete und verschraubte Totalprothesen mit distalen Extensionen (Hybridprothesen). Als Verankerung dienten Osseotiteimplantate in einem zahnlosen Unterkiefer. Methode und Material: Für diese Studie behandelte man in vier klinischen Zentren 62 Patienten. Gemäss einem vorgegebenen Protokoll setzte man 325 Osseotite-Implantate und belastete sie sofort mit Kaukräften. Die provisorischen Prothesen konnten vier Stunden nach der Chirurgie eingegliedert werden. Die definitiven Hybridprothesen setzte man sechs Monate später ein. Den marginalen Knochenverlust beurteilte man mit periapicalen Röntgenbildern, die komputerunterstützt vermessen wurden. Resultate: Bei zwei Implantaten kam es in den ersten zwei Monaten der okklusalen Sofortbelastung zu Misserfolgen. Daraus errechnete sich zwischen dem zwölften und 60. Monat nach Implantation eine kumulative Erfolgsrate aller Implantate von 99.4% (Mittelwert/SD 28.6±14.1 Monate). Der crestale Knochenverlust um die sofortbelastete Implantate war ähnlich wie in anderen Arbeiten mit standartmässig verzögert belasteten Implantaten. Schlussfolgerung: Die Resultate dieser Arbeit lassen vermuten, dass die Rekonstruktion eines zahnlosen Unterkiefers mit okklusal sofortbelasteten Hybridprothesen, abgestützt auf 5 bis 6 Osseotite-Implantaten, eine brauchbare Alternative zu den klassischen Protokollen mit einer verzögerten Belastung darstellt. Resumen Intención: Este trabajo informa sobre los resultados de un estudio prospectivo multicéntrico de prótesis de arco completo implantorretenidas inmediatamente cargadas con extensiones distales (prótesis híbridas) soportadas por implantes Osseotite insertados en mandíbulas edéntulas. Método y Material: Se enroló a 62 pacientes en cuatro centros clínicos. Se insertaron 325 implantes Osseotite y se cargaron oclusalmente de acuerdo con un protocolo de carga inmediata. La prótesis temporal se suministró a las cuatro horas de la cirugía. La prótesis definitiva se suministró a los seis meses. La pérdida de hueso marginal se monitorizó de radiografías periapicales usando una técnica computarizada. Resultados: Dos implantes fracasaron al integrarse dentro de los dos meses de carga oclusal. Se logró un índice de éxito acumulado de implantes del 99.4% durante un periodo de 12 a 60 meses tras el tratamiento (media 28.6±14.1 (SD) meses). La pérdida de hueso crestal alrededor implantes cargados inmediatamente fue similar a aquellos informados para protocolos de carga diferida estándar. Conclusión: Los resultados de este estudio sugieren que la rehabilitación de la mandíbula edéntula por medio de una prótesis híbrida de carga oclusal inmediata soportada por 5,6 implantes Osseotite representa una alternativa viable de tratamiento frente a los protocolos clásicos de carga diferida. [source] | ||||||||||