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Removable Partial Dentures (removable + partial_denture)
Kinds of Removable Partial Dentures Selected AbstractsProvisional Prosthetic Management of Mobile Teeth in Conjunction with a Removable Partial Denture Using Orthodontic WireJOURNAL OF PROSTHODONTICS, Issue 7 2009Won-suk Oh DDS Abstract Precision attachment-retained removable partial dentures eliminate the use of visible clasps and improve the esthetic appearance of the smile; however, terminal abutment teeth may be subject to unfavorable stresses under function when misused. A provisional prosthetic management technique that incorporates an orthodontic wire to assist cross-arch support and stability of the periodontally weakened abutment teeth is described. This technique is simple, reversible, does not alter the esthetic appearance of the smile, and controls the mobility of the abutment teeth until a definitive treatment plan is established. [source] Severe periodontal damage by an ultrasonic endodontic device: a case reportDENTAL TRAUMATOLOGY, Issue 2 2007John D. Walters Abstract,,, Heat produced within a root canal during use of an ultrasonic instrument can be conducted through the dentin into periodontal ligament, bone and soft tissue. If severe in intensity or long in duration, it can induce damage to these tissues. This report describes a case in which an ultrasonic endodontic instrument apparently induced severe damage to alveolar bone, gingiva and nasal mucosa in a 42-year-old female. Overheating of a maxillary central incisor caused necrosis of soft tissue and bone on the facial and mesial aspects and triggered a protracted inflammatory response in the adjacent nasal cavity. To relieve the severe discomfort associated with this damage, the patient chose to have her maxillary incisors extracted and replaced by a removable partial denture. A defect in the soft tissue and bone was present at a follow-up visit 10 months after the extractions. While morbidity of this nature is rare, this case reinforces the need to maintain adequate cooling of ultrasonic instruments. [source] Effect of direct retainer and major connector designs on RPD and abutment tooth movement dynamicsJOURNAL OF ORAL REHABILITATION, Issue 11 2008H. ITOH Summary, Designs of removable partial dentures are suggested to affect the mobility of abutment teeth and removable partial denture (RPD) during oral functions. This study aimed to examine the effect of direct retainer and major connector designs on RPD dynamics under simulated loading. Six different Kennedy class II maxillary RPDs were fabricated on a maxillary model. These dentures involved 3 different direct retainers (wrought-wire clasp, RPA clasp, and conical crown telescopic retainer) and 2 different major connectors (Co-Cr major connector and heat-cured acrylic resin with a metal strengthener). Using an experimental model with simulated periodontal ligaments and mucosa that were fabricated using silicone impression material, three-dimensional displacements of the RPDs were measured under a simulated 30-N loading with a displacement transducer type M-3. Significant effects of "direct retainer design" on bucco-palatal displacements and "major connector" on mesio-distal displacements were revealed by 2 × 3 two-way analysis of variance of abutment teeth movements (P < 0·001 and P = 0·002, respectively). Additionally, analysis of variance of RPD displacements revealed significant effects of "direct retainer design" on corono-apical displacements and "major connector" on mesio-distal displacements (P = 0·001 and P = 0·028, respectively). Rigid direct retainers and rigid major connectors decrease the movements of both abutment tooth and RPD. [source] Detection of improvement in the masticatory function from old to new removable partial dentures using mixing ability testJOURNAL OF ORAL REHABILITATION, Issue 9 2005A. ASAKAWA summary, The aim of this study was to determine the sensitivity of the Mixing Ability Test to detect improvement of masticatory function in subjects on transition from old to new removable partial dentures. Thirty-two subjects (seven males, 25 females, mean age 65·0 years) with distal extension partially edentulous area in mandible and/or maxilla participated in the study. The following reasons were presented for replacing the old removable partial dentures with new ones: fracture and/or poor fitness of retainers, extraction of abutment teeth, poor fitness of denture base, severe wear of artificial teeth and request for metal base dentures. Masticatory function with old and new removable partial dentures after an adaptation period (mean 27·4 weeks) was evaluated by the Mixing Ability Test. Subjects were asked to masticate five two-coloured wax cubes with each removable partial denture. Mixing Ability Index was obtained from the colour mixture and shape of the masticated cubes. Wilcoxon signed-rank test was used to test the difference of Mixing Ability Indexes between old and new removable partial dentures. The mixing ability indexes with new removable partial dentures (mean ± s.d.: 0·70 ± 0·68) was significantly higher (P < 0·001) than those with old removable partial dentures (,0·11 ± 1·13). The results suggest that the Mixing Ability Test was capable of detecting improvement in masticatory function with new removable partial dentures. [source] A survey of treatment outcomes with removable partial denturesJOURNAL OF ORAL REHABILITATION, Issue 8 2003D. Knezovi, Zlatari summary The patient's satisfaction with removable partial denture (RPD) therapy has become an increasingly important factor in prosthetic treatment. This study examined patients' satisfaction with RPDs in relation to some socio-economic variables, patients' habits of wearing and cleaning RPDs, comfort of wearing RPDs and different RPDs characteristics. A questionnaire was devised for the purpose. Two hundred and five patients were required to assess satisfaction with RPDs. They graded RPDs, depending on the level of satisfaction, on scale ranging from 1 to 5. A dentist determined Kennedy classification, material and denture support, denture base shape, number of missing teeth and evaluated denture construction. Majority of the patients were satisfied with the prosthesis. The patients of a higher education level gave lower grades (P < 0·05) to aesthetics of maxillary RPDs. Almost half of the patients were wearing RPDs during the day. Most of the patients cleaned RPDs three times a day. A significant difference was found between the patients' grades for comfort of wearing mandibular RPDs and number of missing teeth and between hygiene of mandibular RPDs and habits of cleaning them. Majority of the patients treated with RPDs were satisfied with the prosthesis. Dissatisfaction was related to mastication, esthetics, number of missing teeth and maintenance of oral hygiene. [source] Treatment with removable partial dentures: a longitudinal study.JOURNAL OF ORAL REHABILITATION, Issue 5 2003Part II summary The aim of this study was to evaluate the effectiveness of an oral rehabilitation by removable partial denture (RPD). Between 1983 and 1994, 629 patients were provided with an RPD at the Dental School of the Université catholique de Louvain. All the RPDs were constructed with a cobalt,chromium framework. All the treatments were provided by dental students under the supervision of clinical instructors. At recall time (1998,2000), 269 patients could not be reached neither by telephone nor by mail and 27 had died. Consequently, 333 patients were called for clinical examination and 254 of these (76·3%) actually attended. For a total of 292 RPDs checked 1893 persistent teeth were listed, with 804 serving as abutments; more than half (57·6%) of these were crowned, for which 51 debondings were recorded. For the period of observation we listed 79 abutments lost (37 at the upper jaw and 42 at the lower jaw), i.e. 9·8% of the total number of abutments. No relation could be established between the type of the abutments (natural or crowned teeth) and the losses observed (Test of Mantel-Haenszel: P=0·9496). In the upper jaw, the percentage of abutments lost was significantly higher in the presence of free-end edentulous areas as compared with bounded edentulous areas (Test of Mantel-Haenszel: P=0·0002); this difference does not appear for the lower jaws (P=0·9558). If we deduct the 25 abutments related with the 11 non-worn RPDs and the 79 abutments lost, no change becomes apparent for 92·2% of the maxillary abutments and for 85·8% of the mandibular abutments. For the 1089 other teeth, we observed the loss of 40 teeth and the appearance of caries or new fillings for 95 teeth. The fractures of cast clasps represent 3·4%. [source] Influence of working side contacts on masticatory function for mandibular distal extension removable partial denturesJOURNAL OF ORAL REHABILITATION, Issue 3 2003S. Sueda summary The aim of this study was to clarify the influence of working side contacts for masticatory function for a distal extension removable partial denture. Five subjects who had edentulous arches from second premolar to second molar opposing natural teeth participated. Working side contacts were altered by using three types of artificial teeth attached to the denture base. A-form teeth made contact with opposite teeth while acting as the working side in a lateral excursion. The cusp angles of B- and C-form teeth were decreased by 10° and 20°, respectively compared with A-form teeth. B-and C-form teeth discluded with opposite teeth on the working side. Subjects were asked to perform two kinds of masticatory performance test. Obtained data were evaluated by the repeated-measures anova and the Tukey test for multiple comparisons. Results revealed that there was a significant difference (P=0·001) in the three types of teeth in the mixing ability test and the value of A-form teeth was statistically less value than those of the other teeth. However, there was no significant difference in the comminuting ability test. These results suggested that working side contacts between artificial teeth and opposite natural teeth influenced mixing ability, but not comminuting ability. [source] ICK Classification System for Partially Edentulous ArchesJOURNAL OF PROSTHODONTICS, Issue 6 2008Sulieman S. Al-Johany BDS Abstract Several methods of classification of partially edentulous arches have been proposed and are in use. The most familiar classifications are those originally proposed by Kennedy, Cummer, and Bailyn. None of these classification systems include implants, simply because most of them were proposed before implants became widely accepted. At this time, there is no classification system for partially edentulous arches incorporating implants placed or to be placed in the edentulous spaces for a removable partial denture (RPD). This article proposes a simple classification system for partially edentulous arches with implants based on the Kennedy classification system, with modification, to be used for RPDs. It incorporates the number and positions of implants placed or to be placed in the edentulous areas. A different name, Implant-Corrected Kennedy (ICK) Classification System, is given to the new classification system to be differentiated from other partially edentulous arch classification systems. [source] Load transfer characteristics of unilateral distal extension removable partial dentures with polyacetal resin supporting componentsAUSTRALIAN DENTAL JOURNAL, Issue 1 2009T Jiao Abstract Background:, To photoelastically examine load transfer by unilateral distal extension removable partial dentures with supporting and retentive components made of the lower stiffness polyacetal resins. Methods:, A mandibular photoelastic model, with edentulous space distal to the right second premolar and missing the left first molar, was constructed to determine the load transmission characteristics of a unilateral distal extension base removable partial denture. Individual simulants were used for tooth structure, periodontal ligament, and alveolar bone. Three designs were fabricated: a major connector and clasps made from polyacetal resin, a metal framework as the major connector with polyacetal resin clasp and denture base, and a traditional metal framework I-bar removable partial denture. Simulated posterior bilateral and unilateral occlusal loads were applied to the removable partial dentures. Results:, Under bilateral and left side unilateral loading, the highest stress was observed adjacent to the left side posterior teeth with the polyacetal removable partial denture. The lowest stress was seen with the traditional metal framework. Unilateral loads on the right edentulous region produced similar distributed stress under the denture base with all three designs but a somewhat higher intensity with the polyacetal framework. Conclusions:, The polyacetal resin removable partial denture concentrated the highest stresses to the abutment and the bone. The traditional metal framework I-bar removable partial denture most equitably distributed force. The hybrid design that combined a metal framework and polyacetal clasp and denture base may be a viable alternative when aesthetics are of primary concern. [source] Orthodontic and prosthetic rehabilitation of unilateral free-end edentulous spaceAUSTRALIAN DENTAL JOURNAL, Issue 4 2006SG Arslan Abstract Most patients prefer fixed dentures, even in the presence of uni and bilateral free-end saddle. The most suitable treatment for this is an implant or implant-supported prosthetic restoration. A combined prosthetic and orthodontic treatment with distalization of a posterior tooth towards the edentulous region is an alternative approach. This study involved a 34.3 year old female patient who had a free-end edentulous space on the left mandibula and missing 1st and 3rd molars on the right mandibula. The patient was offered both a removable partial denture and implant treatment options. A detailed explanation of her situation and suitable treatments were given but she refused both options. Therefore, an alternative combined treatment involving prosthodontic and orthodontic disciplines was performed. The second premolar tooth was distalized orthodontically and used as a distal bridge abutment. After 65 months, prosthetic restoration was functional and abutment teeth and periodontium were pathology free, and the patient was satisfied with the results. [source] Treatment planning for replacing missing teeth in UK general dental practice: current trendsJOURNAL OF ORAL REHABILITATION, Issue 7 2010P. M. PATEL Summary, The aim of this study was to examine the confidence, barriers and attitudes towards the replacement of missing teeth by general dental practitioners (GDPs). The perceived impact of the recently introduced National Health Service (NHS) contract on the provision of prosthodontic treatments was also considered. Pre-piloted postal questionnaires were mailed to 500 GDPs in Wales. Open- and closed-ended questions were utilised to establish confidence, adequacy of training and attitudes towards treatments for replacing missing teeth. Two hundred and seventeen completed questionnaires were received (response rate = 43·4%). Many respondents described themselves as ,confident' or ,very confident' in the provision of removable partial dentures (RPDs) (acrylic = 100%, metal based = 99·5%), cantilever resin-bonded bridges (94·4%) and conventional bridgework (98·6%). GDPs were ,not confident' providing fixed-fixed resin-bonded bridges (21·1%) or implants (81·4%). Financial barriers were identified to the provision of prosthodontic treatments, including comments such as "the new [National Health Service] contract does limit the treatments available". Privately funded patients were more likely to be offered a fixed bridge or implant replacement of a missing upper first molar, whereas non-privately funded patients were more likely to be offered no treatment (P < 0·01). Most respondents reported confidence at providing more routine forms of prosthodontic care such as RPDs and bridges. It appears that funding arrangements may have an impact on treatments offered to replace missing teeth, particularly under the current NHS contract. [source] Effect of direct retainer and major connector designs on RPD and abutment tooth movement dynamicsJOURNAL OF ORAL REHABILITATION, Issue 11 2008H. ITOH Summary, Designs of removable partial dentures are suggested to affect the mobility of abutment teeth and removable partial denture (RPD) during oral functions. This study aimed to examine the effect of direct retainer and major connector designs on RPD dynamics under simulated loading. Six different Kennedy class II maxillary RPDs were fabricated on a maxillary model. These dentures involved 3 different direct retainers (wrought-wire clasp, RPA clasp, and conical crown telescopic retainer) and 2 different major connectors (Co-Cr major connector and heat-cured acrylic resin with a metal strengthener). Using an experimental model with simulated periodontal ligaments and mucosa that were fabricated using silicone impression material, three-dimensional displacements of the RPDs were measured under a simulated 30-N loading with a displacement transducer type M-3. Significant effects of "direct retainer design" on bucco-palatal displacements and "major connector" on mesio-distal displacements were revealed by 2 × 3 two-way analysis of variance of abutment teeth movements (P < 0·001 and P = 0·002, respectively). Additionally, analysis of variance of RPD displacements revealed significant effects of "direct retainer design" on corono-apical displacements and "major connector" on mesio-distal displacements (P = 0·001 and P = 0·028, respectively). Rigid direct retainers and rigid major connectors decrease the movements of both abutment tooth and RPD. [source] Quality of life and masticatory function in denture wearersJOURNAL OF ORAL REHABILITATION, Issue 5 2006H. KOSHINO summary, Successful prosthodontic treatments for a patient with removable partial dentures including maxillofacial prostheses hopefully brings about psychological wellbeing as well as improved health. The purpose of this study was to investigate the relationship between quality of life (QOL) and the various aspects of denture function. At first, a questionnaire with a visual analog scale with 16 question items concerning denture and/or eating problems, the present state of health, psychological and physical wellbeing, life satisfaction, and QOL was developed. To discuss the validity and reliability of the questionnaire, 48 outpatients who wore a denture were asked to fill it out. Next, to discuss the difference in QOL of the patient with various kinds of dentures and conditions, 103 outpatients were asked to complete the newly developed questionnaire. The questionnaire which contained four factor areas with eight questions for denture patients was developed by factor analysis with Varimax rotation. The reliability of the QOL scale was confirmed by reliability analysis (Cronbach's ,=0·784). The QOL score of edentulous patients with a complete denture having some trouble chewing was significantly lower than that of other denture patients. It was suggested that the wearing of a denture significantly affected the QOL of elderly persons. [source] Detection of improvement in the masticatory function from old to new removable partial dentures using mixing ability testJOURNAL OF ORAL REHABILITATION, Issue 9 2005A. ASAKAWA summary, The aim of this study was to determine the sensitivity of the Mixing Ability Test to detect improvement of masticatory function in subjects on transition from old to new removable partial dentures. Thirty-two subjects (seven males, 25 females, mean age 65·0 years) with distal extension partially edentulous area in mandible and/or maxilla participated in the study. The following reasons were presented for replacing the old removable partial dentures with new ones: fracture and/or poor fitness of retainers, extraction of abutment teeth, poor fitness of denture base, severe wear of artificial teeth and request for metal base dentures. Masticatory function with old and new removable partial dentures after an adaptation period (mean 27·4 weeks) was evaluated by the Mixing Ability Test. Subjects were asked to masticate five two-coloured wax cubes with each removable partial denture. Mixing Ability Index was obtained from the colour mixture and shape of the masticated cubes. Wilcoxon signed-rank test was used to test the difference of Mixing Ability Indexes between old and new removable partial dentures. The mixing ability indexes with new removable partial dentures (mean ± s.d.: 0·70 ± 0·68) was significantly higher (P < 0·001) than those with old removable partial dentures (,0·11 ± 1·13). The results suggest that the Mixing Ability Test was capable of detecting improvement in masticatory function with new removable partial dentures. [source] A survey of treatment outcomes with removable partial denturesJOURNAL OF ORAL REHABILITATION, Issue 8 2003D. Knezovi, Zlatari summary The patient's satisfaction with removable partial denture (RPD) therapy has become an increasingly important factor in prosthetic treatment. This study examined patients' satisfaction with RPDs in relation to some socio-economic variables, patients' habits of wearing and cleaning RPDs, comfort of wearing RPDs and different RPDs characteristics. A questionnaire was devised for the purpose. Two hundred and five patients were required to assess satisfaction with RPDs. They graded RPDs, depending on the level of satisfaction, on scale ranging from 1 to 5. A dentist determined Kennedy classification, material and denture support, denture base shape, number of missing teeth and evaluated denture construction. Majority of the patients were satisfied with the prosthesis. The patients of a higher education level gave lower grades (P < 0·05) to aesthetics of maxillary RPDs. Almost half of the patients were wearing RPDs during the day. Most of the patients cleaned RPDs three times a day. A significant difference was found between the patients' grades for comfort of wearing mandibular RPDs and number of missing teeth and between hygiene of mandibular RPDs and habits of cleaning them. Majority of the patients treated with RPDs were satisfied with the prosthesis. Dissatisfaction was related to mastication, esthetics, number of missing teeth and maintenance of oral hygiene. [source] Treatment with removable partial dentures: a longitudinal study.JOURNAL OF ORAL REHABILITATION, Issue 5 2003Part II summary The aim of this study was to evaluate the effectiveness of an oral rehabilitation by removable partial denture (RPD). Between 1983 and 1994, 629 patients were provided with an RPD at the Dental School of the Université catholique de Louvain. All the RPDs were constructed with a cobalt,chromium framework. All the treatments were provided by dental students under the supervision of clinical instructors. At recall time (1998,2000), 269 patients could not be reached neither by telephone nor by mail and 27 had died. Consequently, 333 patients were called for clinical examination and 254 of these (76·3%) actually attended. For a total of 292 RPDs checked 1893 persistent teeth were listed, with 804 serving as abutments; more than half (57·6%) of these were crowned, for which 51 debondings were recorded. For the period of observation we listed 79 abutments lost (37 at the upper jaw and 42 at the lower jaw), i.e. 9·8% of the total number of abutments. No relation could be established between the type of the abutments (natural or crowned teeth) and the losses observed (Test of Mantel-Haenszel: P=0·9496). In the upper jaw, the percentage of abutments lost was significantly higher in the presence of free-end edentulous areas as compared with bounded edentulous areas (Test of Mantel-Haenszel: P=0·0002); this difference does not appear for the lower jaws (P=0·9558). If we deduct the 25 abutments related with the 11 non-worn RPDs and the 79 abutments lost, no change becomes apparent for 92·2% of the maxillary abutments and for 85·8% of the mandibular abutments. For the 1089 other teeth, we observed the loss of 40 teeth and the appearance of caries or new fillings for 95 teeth. The fractures of cast clasps represent 3·4%. [source] The effect of three different periodontal pre-treatment procedures on the success of telescopic removable partial denturesJOURNAL OF ORAL REHABILITATION, Issue 4 2003R. Polansky summary, In this prospective study, 120 teeth consisting of maxillary and mandibular canines and premolars were divided into three groups each containing 40 teeth. The teeth were assigned randomly in quadrants to three different periodontal treatment protocols. The first group was treated with professional prophylaxis only. The second group received additional deep scaling. With the third group, additional surgical periodontal flap surgery and scaling was performed. Both papillary bleeding index (PBI) and probing depth (PD) were evaluated before, during and after treatment. During the subsequent prosthetic treatment phase all teeth were then used as telescope abutments supporting a removable prosthesis. The documentation of the attachment level (AL) was then used as a clinical parameter. One year after the incorporation of telescopic removable partial dentures (RPDs), PD, PBI and AL were again evaluated. The resulting periodontal parameters were compared between the different groups using the general linear model (GLM) repeated measures and the Kruskal,Wallis test for non-parametric variables. Differences within the three treatment groups were determined using the t -test, e.g. the Wilcoxon test for dependent variables (P < 0·05). A significant decrease in inflammatory indices (PBI) was found for all types of periodontal treatment (P < 0·03 for all groups). Additionally, the reduction in PD was significant for all of the three groups (P < 0·001 for all groups). The greatest reduction in PD was observed in the group in which a surgical approach was used. Evaluation of the attachment level after the incorporation of the telescopic RPDs showed that tooth position did not influence the periodontal prognosis and that the use of telescopic RPDs exerted no ascertainable negative influence on the periodontium of the abutment teeth. [source] Influence of working side contacts on masticatory function for mandibular distal extension removable partial denturesJOURNAL OF ORAL REHABILITATION, Issue 3 2003S. Sueda summary The aim of this study was to clarify the influence of working side contacts for masticatory function for a distal extension removable partial denture. Five subjects who had edentulous arches from second premolar to second molar opposing natural teeth participated. Working side contacts were altered by using three types of artificial teeth attached to the denture base. A-form teeth made contact with opposite teeth while acting as the working side in a lateral excursion. The cusp angles of B- and C-form teeth were decreased by 10° and 20°, respectively compared with A-form teeth. B-and C-form teeth discluded with opposite teeth on the working side. Subjects were asked to perform two kinds of masticatory performance test. Obtained data were evaluated by the repeated-measures anova and the Tukey test for multiple comparisons. Results revealed that there was a significant difference (P=0·001) in the three types of teeth in the mixing ability test and the value of A-form teeth was statistically less value than those of the other teeth. However, there was no significant difference in the comminuting ability test. These results suggested that working side contacts between artificial teeth and opposite natural teeth influenced mixing ability, but not comminuting ability. [source] Usage and status of cobalt,chromium removable partial dentures 5,6 years after placementJOURNAL OF ORAL REHABILITATION, Issue 2 2002A. L. P. Yeung The aim of this study was to describe the usage of cobalt,chromium (Co,Cr) removable partial dentures (RPDs) by patients 5,6 years after denture insertion and to find out the factors that affected their denture usage. A random sample of patients provided with Co,Cr RPDs from a dental teaching hospital in Hong Kong was selected. Patients were interviewed using a structured questionnaire concerning their assessment and use of the dentures. Those who had been constantly wearing their original RPDs were examined by one calibrated examiner under optimal clinical conditions. The response rate of the patients who could be contacted was 98%. The results from 189 patient interviews showed that usage of the RPDs declined with time and that half of the dentures had been discarded or replaced 5,6 years after insertion. These discarded RPDs had been in use for an average of 19·5 months. The main reason given by the patients for not using the RPDs was general dissatisfaction with the dentures in various combinations of comfort, fit and chewing ability and, less importantly, with food trapping and appearance. No statistically significant association between denture usage and their respective Kennedy classification was found. The status of the Co,Cr RPDs that had been constantly used for 5,6 years was generally good. The majority of these RPDs demonstrated fair to good cleanliness, stability and retention and had no defect of any sort. [source] Finite element analysis on preferable I-bar clasp shapeJOURNAL OF ORAL REHABILITATION, Issue 5 2001Y. Sato An I-bar clasp is one of the most popular direct retainers for distal-extension removable partial dentures. However, no adequate information is available on preferable shape as determined by biomechanics. This study aimed (1) to investigate, by finite element analysis (FEA), the dimensions and stress of I-bar clasps having the same stiffness, and (2) to estimate a mechanically preferable clasp design. Three-dimensional FEA models of I-bar clasps were created with vertical and horizontal straight sections connected by a curved section characterized by six parameters: thickness of the clasp tip, width of the clasp tip, radius of the curvature, horizontal distance between the base and the vertical axis, vertical dimension between the tip and the horizontal axis, and taper (change of width per unit length along the axis). Stress was calculated with a concentrated load of 5 N applied 2 mm from the tip of the clasp in the buccal direction. A thinner and wider clasp having an taper of 0·020,0·023 and radius of curvature of 2·75,3·00 showed less stress. The results suggest that such a shape might be the preferable I-bar clasp shape as biomechanical viewpoint. [source] Dimensional measurement and finite element analysis of I-bar clasps in clinical useJOURNAL OF ORAL REHABILITATION, Issue 11 2000Y. Sato An I-bar clasp is a popular retainer for distal-extension removable partial dentures. However, there have been almost no evidence-based criteria on the mechanically preferable shape. The present study aimed to investigate the variations of dimension in I-bar clasps used in patients, and to clarify the effect of the variations on stiffness and stress of I-bar clasps by finite element analysis. Dimensions (thickness, width, taper, radius of curvature, length, relation to oral structures) of 23 I-bar clasps were measured. A three-dimensional finite element model was made for each measured I-bar clasp with vertical and horizontal straight sections connected with a curved section. A concentrated load of 5 N was applied at the lowest point of the tip that contacted the abutment in the buccal direction. Maximal equivalent stress and stiffness of each clasp were evaluated. The measured dimension, stiffness, and maximum stress showed wide variations. Mean stiffness was far from the proper one, and mean stress was near the proportional limit of Co,Cr alloy. Considering the stiffness and stresses in this study, only six clasps out of 23 were appropriate. These results suggest that evidence-based criteria of preferable shape of I-bar clasps should be determined. [source] A clinical diagnosis of diurnal (non-sleep) bruxism in denture wearersJOURNAL OF ORAL REHABILITATION, Issue 6 2000K. Piquero The purpose of this study was to establish a clinical method for diagnosing diurnal bruxism in denture wearers by recording masseter and anterior temporal electromygraph (EMG) activity. Seven suspected bruxists and five normal patients who wore complete dentures and/or distal extension base removable partial dentures were selected for participation. EMG activity in both the masseter and the anterior temporal muscles was recorded bilaterally during silent reading (10 min), maximal voluntary clenching (MVC), tapping in centric occlusion, lateral movements, chewing and swallowing. No significant differences of EMG activity were found between the groups during tapping, lateral movement, chewing and swallowing (P>0·05). However, during 10 min of silent reading, a significant difference was found between the groups when comparing masseter muscle activity (P<0·05). A threshold of 10% of MVC of at least 3-s duration was used to define an individual bruxism event. When the muscle activity recorded during silent reading was further analysed using these criteria, the control group displayed no bruxing activity while the suspected bruxist group displayed a mean frequency of six bruxism events (range 2,10). It was concluded that: (a) masseter muscle activity recorded during 10 min of silent reading showed significant difference between the groups; (b) the criteria selected in this study for the detection of sleep bruxism can also be used to assess diurnal bruxism; and (c) it is possible to diagnose diurnal bruxism in denture wearers by measuring the masseter EMG activity during 10 min of silent reading. [source] Provisional Prosthetic Management of Mobile Teeth in Conjunction with a Removable Partial Denture Using Orthodontic WireJOURNAL OF PROSTHODONTICS, Issue 7 2009Won-suk Oh DDS Abstract Precision attachment-retained removable partial dentures eliminate the use of visible clasps and improve the esthetic appearance of the smile; however, terminal abutment teeth may be subject to unfavorable stresses under function when misused. A provisional prosthetic management technique that incorporates an orthodontic wire to assist cross-arch support and stability of the periodontally weakened abutment teeth is described. This technique is simple, reversible, does not alter the esthetic appearance of the smile, and controls the mobility of the abutment teeth until a definitive treatment plan is established. [source] Metallic dental materials in patient's oral cavity acting as electrodes of electrochemical cellsMATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 7 2004W. Opydo Abstract The work was aimed at studying of standard potentials of commonly used metallic dental materials and determining of the effect of saliva conductivity and reaction on value of the potentials. The following materials have been examined: gold alloy (a material used for crowns and bridgeworks), chromium-cobalt alloy (for frameworks in removable partial dentures), and silver amalgams (used for fillings) manufactured by three different companies. Taking into account that mucosa makes one of the electrodes existing in oral cavity the rest potentials of mucosa have been in vivo measured in several patients. Their values, converted with respect to NHE, oscillated within the range from + 0.31 V to + 0.47 V. Among metallic dental materials examined in the experiment maximal standard potential was found for the gold alloy, further materials having lower potentials, in decreasing order, were chromium-cobalt alloy, and the amalgams Amalcap Plus, ANA 2000 and Septalloy. Significant differences between standard potentials of examined materials and mucosa indicate spontaneous formation of galvanic cells of electromotive force reaching even about 0.6 V. [source] Dental findings and rehabilitation in familial osteodysplasia (Anderson type): a case reportORAL DISEASES, Issue 2 2006S Deger Familial osteodysplasia is a disorder of osteogenesis with an autosomal recessive pattern of inheritance which predominantly affects facial bones. No recent case had been reported, particularly from a dental point of view since the syndrome was first described by Anderson et al (JAMA 1972;220:1687,93). A 23-year-old male with familial osteodysplasia was presented in maxillofacial and dental aspects with clinical and radiological manifestations including malocclusion, abnormal teeth alignment, impacted teeth, shape disturbances including uncompleted coronal formation, root shortening with bulbous form, high angled mandible and elongation of the corpus of mandible. Recognation of the syndromal features prior to any dental intervention is of paramount importance because of increased inclination to spontaneous mandibular fractures. Hence, no surgical intervention was performed for impacted teeth. Following the extractions of severely mobile teeth, a definitive restoration was fabricated as distal-extension removable partial dentures with conus crown telescopic system. The aesthetic and functional outcome was satisfactory for the patient. In conclusion, dentists appear to play an important role in the recognition of familial osteodysplasia, based on maxillofacial and dentoalveolar findings. Awareness of the syndromal features, especially of spontaneous fractures, would detect the limitations for dental interventions and treatment planning. [source] Load transfer characteristics of unilateral distal extension removable partial dentures with polyacetal resin supporting componentsAUSTRALIAN DENTAL JOURNAL, Issue 1 2009T Jiao Abstract Background:, To photoelastically examine load transfer by unilateral distal extension removable partial dentures with supporting and retentive components made of the lower stiffness polyacetal resins. Methods:, A mandibular photoelastic model, with edentulous space distal to the right second premolar and missing the left first molar, was constructed to determine the load transmission characteristics of a unilateral distal extension base removable partial denture. Individual simulants were used for tooth structure, periodontal ligament, and alveolar bone. Three designs were fabricated: a major connector and clasps made from polyacetal resin, a metal framework as the major connector with polyacetal resin clasp and denture base, and a traditional metal framework I-bar removable partial denture. Simulated posterior bilateral and unilateral occlusal loads were applied to the removable partial dentures. Results:, Under bilateral and left side unilateral loading, the highest stress was observed adjacent to the left side posterior teeth with the polyacetal removable partial denture. The lowest stress was seen with the traditional metal framework. Unilateral loads on the right edentulous region produced similar distributed stress under the denture base with all three designs but a somewhat higher intensity with the polyacetal framework. Conclusions:, The polyacetal resin removable partial denture concentrated the highest stresses to the abutment and the bone. The traditional metal framework I-bar removable partial denture most equitably distributed force. The hybrid design that combined a metal framework and polyacetal clasp and denture base may be a viable alternative when aesthetics are of primary concern. [source] Willingness to pay for implant therapy: a study of patient preferenceCLINICAL ORAL IMPLANTS RESEARCH, Issue 8 2010Katherine C. M. Leung Abstract Aims: This study determined the amount of willingness to pay (WTP) for implant treatment and identified the factors affecting WTP. Methods: Subjects attending a university dental hospital were recruited (n=59). They were presented with two hypothetical clinical scenarios: missing one anterior/posterior tooth. The clinical procedures, outcome and plausible complications of various replacement options (fixed and removable partial dentures, implants) and sequelae of no treatment were presented. They were then asked how much they were willing to pay for tooth replacement under the two situations using a bidding method, with a starting bid of Hong Kong (HK)$20,000 in HK$1000 increment/decrement if they were willing/unwilling to pay that amount (1 USD=7.8 HKD). The amount was recorded at which the subject chose the opposite option or it reached HK$0. Demographic data were also collected. WTP values were compared between anterior and posterior replacements, and among various demographic subgroups. Spearman's correlations and linear regression analysis were also conducted. Results: Ninety-four percent and 84% of the subjects chose implant treatment to replace missing anterior and posterior teeth, respectively. The mean WTP amounts for anterior/posterior tooth replacement were HK$11,000/HK$10,000 (P>0.05). Higher WTP amounts were obtained from females, subjects without missing teeth or restorative need, and had attained higher level of education (P<0.05). Gender (P<0.05), level of education (P=0.042), and the presence of missing teeth (P=0.001) were independent predictors of WTP. Conclusions: The estimated WTP value for a single tooth replacement using dental implants was HK$10,000. Gender, level of education and presence of missing teeth were independent predictors that influenced WTP. To cite this article: Leung KCM, McGrath CPJ. Willingness to pay for implant therapy: a study of patient preference. Clin Oral Impl Res. 21, 2010; 789,793. doi: 10.1111/j.1600-0501.2009.01897.x [source] Longitudinal study on periodontal conditions in healthy elderly people in JapanCOMMUNITY DENTISTRY AND ORAL EPIDEMIOLOGY, Issue 6 2002Toshinobu Hirotomi Abstract , Objectives: A strategy for the control of periodontal disease progression is required to prevent tooth loss in older people. However, detailed epidemiological data on periodontal conditions in elderly people is limited. The purpose of the present study is to describe the natural history of periodontal disease and to evaluate the intraoral factors relating to the disease progression in systemically healthy elderly people. Methods: In the cross-sectional study, 599 and 162 subjects aged 70 and 80 years, respectively, were examined. Of those subjects aged 70 years, 436 (73%) participated in the 2-year longitudinal study. Pocket depth (PD) and attachment level (AL) were measured for all functioning teeth at six sites per tooth. In the cross-sectional study, AL of 4 mm or greater and 7 mm or greater were defined as moderate and severe disease, respectively. In the longitudinal study, a change in AL of 3 mm or greater at each site was defined as periodontal disease progression. Results: In the cross-sectional study, 97.1% of the subjects had at least one site of AL of 4 mm or greater (4+ mm). The prevalence of AL of 7 mm or greater (7+ mm) was 47.9%, with 2.8 affected teeth per person in those with AL 7+ mm. These findings reveal that periodontal disease is extremely widespread in the elderly population. However, very few had many teeth with severe periodontal conditions. In the longitudinal study, 75.1% experienced attachment loss of 3 mm or greater (3+ mm) during the 2-year study period. Of those subjects who experienced attachment loss, a mean of 4.7 teeth exhibited attachment loss. Multivariate logistic regression showed that both the highest AL in each tooth at baseline and abutment teeth for removable partial dentures were significantly related to periodontal disease progression as well as tooth loss incidence. Conclusions: These results suggest that teeth with poor periodontal conditions as well as abutment teeth for removable partial dentures were significant intraoral factors relating to periodontal disease progression as well as tooth loss. [source] | ||||||||||