Effect of Labial Implant Inclination on the Retention and Stability of Different Resilient Stud Attachments for Mandibular Implant Overdentures: An In vitro Study.

PURPOSE: This study evaluated the influence of labial implant inclination on the retention and stability of different resilient stud attachments for mandibular implant overdentures. MATERIALS AND METHODS: Four identical mandibular edentulous acrylic resin models were fabricated. For each model, two implants were inserted at the canine areas with different degrees of labial inclination: 0, 10, 20, and 30 degrees. Four experimental overdentures were fabricated over the models and fitted to the implants using resilient stud attachments. Regular retentive inserts (extra-light, light, and medium retention) were used for all implant inclinations, and extended-range inserts (extra-light and medium retention) were used for 30-degree inclination only. Vertical (retention) and oblique (stability) dislodging forces (lateral, anterior, and posterior) were evaluated initially (initial retention) and after overdenture insertion and removal (final retention). RESULTS: After repeated insertions and removals, inclination of 30 degrees recorded the highest retention and lateral stability, and 0 degrees recorded the highest posterior stability; 20 degrees showed the lowest retention, and 30 degrees recorded the lowest posterior stability. The highest stability and retention values were recorded with light and medium regular inserts, and the lowest values were noted with extra-light regular inserts. CONCLUSION: Within the limits of this study, moderate labial implant inclination (10 degrees and 20 degrees) was shown to negatively affect retention and anterior/lateral stability, and excessive implant inclination (30 degrees) to negatively affect posterior stability. When implants are inclined labially, it is recommended to use light and medium regular stud attachments to obtain high levels of retention and stability for two-implant-retained overdentures.

Load Transfer Characteristics of Three-Implant-Retained Overdentures with Different Interimplant Distances.

PURPOSE: Implant-retained overdentures are the first choice of rehabilitation for edentulous mandibles. Bone morphology and anatomical landmarks may be influenced by the location and angulation of implants and distances between the implants. The purpose of this study was to investigate stress distribution characteristics and to compare stress levels of three different attachment designs of three-implant-retained mandibular overdentures with three different interimplant distances. MATERIALS AND METHODS: Three photoelastic mandibular models with three implants were fabricated using an edentulous mandible cast with moderate residual ridge resorption. The center implants were embedded parallel to the midline, and the distal implants were aligned at a 20-degree angulation corresponding to the center implants. Distances between the center and distal implants were set at 11, 18, and 25 mm at the photoelastic models. Bar, bar-ball, and Locator attachment-retained overdentures were prepared for the models. Vertical loads were applied to the overdentures, and stress levels and distribution were evaluated by a circular polariscope. RESULTS: The greatest observed stress level was moderate for the tested overdenture designs. The Locator attachment system showed the lowest stress level for the 11-mm and 25-mm photoelastic models. The bar attachment design transmitted less stress compared with the other tested designs for the 18-mm photoelastic model. CONCLUSION: Stresses were observed on the loaded side of the photoelastic models. The lowest stress was found with the Locator and bar attachments for the 11-mm photoelastic model, which transmitted little or no discernible stress around the implants.

The Influence of Bone Quality on the Biomechanical Behavior of a Tooth-Implant Fixed Partial Denture: A Three-Dimensional Finite Element Analysis.

PURPOSE: The purpose of this study was to evaluate whether or not bone quality has an effect on the biomechanical behavior of a tooth connected to an implant, when a rigid and a nonrigid attachment are used. MATERIALS AND METHODS: Models of fixed partial dentures supported by a tooth and an implant were developed. These models were then imported into finite element analysis software to study the impact of forces on different types of attachments (rigid vs nonrigid) and bones (types 1 to 4). Each fixed partial denture was subjected to a vertical load of 200 N on the premolars and 230 N on the molar. The materials were considered linear, isotropic, and homogenous. Eight different scenarios were tested. The von Mises criterion was used to display the stress in five structures: fastening screw, implant, attachment, cortical, and trabecular bone. The displacements of the tooth and the implant were also examined. RESULTS: The calculated maximum observed stress values differed among the simulated scenarios. The biggest values of stress concentrations were observed at the lingual cervical areas, the implant-cortical bone interface, the implant-crown interface, the butt-joint contact of the implant-abutment screw, and the apical parts of the tooth and implant. The main difference between the rigid and nonrigid connection was observed between the natural tooth retainer and the pontic. In the rigid connection, the movement of the natural tooth retainer was smooth. In the nonrigid connection, the attachment exhibited a partial buccal displacement. Von Mises stresses among the different tested structures ranged between 24 and 840 MPa. CONCLUSION: The quality of the bone and the rigidity of the connection between a natural tooth and an implant influence both the generated stresses and the displacement of the tooth and the implant. The highest stresses for the implant-trabecular bone interface, the neck of the implant, and the fastening screw were observed in type 3 bone when a rigid connection was used. The lowest stresses for the implant-cortical bone interface, the neck of the implant, and the connector were registered in type 1 bone, when a rigid connection was used. The smallest tooth and implant displacement was observed in type 1 bone, when a rigid connection was used, while the biggest tooth and implant displacement was registered in type 4 bone when a nonrigid connection was used.

Effects of Reinforcement on Denture Strain in Maxillary Implant Overdentures: An In Vitro Study Under Various Implant Configurations.

PURPOSE: Maxillary implant overdentures are often designed without palatal coverage to maximize wearer comfort. Although palateless dentures have been reported to be less rigid than conventional dentures, and require reinforcement to prevent complications, there is little documentation about the effects of such reinforcement. The purpose of this study was to examine the effects of reinforcement on the strain on maxillary implant overdentures supported by implants in a variety of configurations. MATERIALS AND METHODS: A maxillary edentulous model with implants inserted in the anterior, premolar, and molar area was fabricated. Five types of experimental overdentures, with and without reinforcement, were fabricated, and two strain gauges were attached at the anterior midline of the labial and palatal sides. A vertical occlusal load of 98 N was applied through a mandibular complete denture, and the shear strain on the denture was measured. The measurements were compared using the Kruskal-Wallis test (P = .05). RESULTS: On both the labial and palatal sides, the strain on the palateless dentures with reinforcement was significantly lower than the strain on palateless dentures without reinforcement in all implant configurations (P < .05). The labial strain on the palateless dentures with reinforcement was almost as low as the labial strain on dentures with palatal coverage in most implant configurations. CONCLUSION: Reinforcement of a palateless implant overdenture with residual ridge reinforcement and a palatal bar could reduce the strain in the anterior midline to almost the same level as a denture with palatal coverage. This type of reinforcement may prevent prosthetic and implant complications.

Retention and Stability of Implant-Retained Mandibular Overdentures Using Different Types of Resilient Attachments: An In Vitro Study.

PURPOSE: The aim of this study was to evaluate and compare the retention and stability of mandibular implant overdentures using different types of resilient attachments. MATERIALS AND METHODS: Two implant analogs were inserted in the canine areas of an acrylic edentulous mandibular model. A metal-reinforced experimental overdenture was constructed and connected to the implant analogs (on two occasions) using either resilient telescopic or Locator attachments. Locators were divided into three subgroups according to the degree of retention of the male nylon insert: Locator extra-light retention (blue insert), Locator light retention (pink insert), and Locator medium retention (transparent insert). Vertical and oblique (anterior, posterior, and lateral) dislodging forces were measured at the beginning of the study (initial retention) and after 540 cycles of denture insertion and removal (final retention). RESULTS: For all dislodging forces, Locator medium recorded the highest initial and final retention. Telescopic attachments recorded the lowest retention during vertical and anterior dislodging, and Locator extra-light recorded the lowest retention during lateral and posterior dislodging. For all types of Locator attachments, anterior dislodging recorded the highest initial and final retention, and lateral dislodging recorded the lowest retention. For the telescopic attachment, posterior dislodgment recorded the highest initial and final retention, and anterior dislodging recorded the lowest retention. CONCLUSION: After repeated denture insertions and removals, the highest retention and stability were recorded with Locator medium followed by Locator light. The lowest retention was recorded with resilient telescopic attachment, and the lowest stability was recorded with Locator extra-light.

A Pilot Study on Mandibular Overdentures Retained By Mini Dental Implants: Marginal Bone Level Changes and Patient-Based Ratings of Clinical Outcome.

PURPOSE: The aim of this study was to investigate the effect of immediately loaded mini dental implants (MDIs) used to support mandibular overdentures on the peri-implant bone level as well as patients' related levels of satisfaction and quality of life. MATERIALS AND METHODS: Four MDIs were placed in the interforaminal region of 10 completely edentulous patients, and the implants were loaded immediately (same day) with an overdenture. Radiographic assessment of the bone loss during a period of 18 months was performed by measuring the bone level changes at the mesial and distal aspects of each implant on panoramic radiographs. At the end of this period, patients' satisfaction level on the visual analog scale (VAS) and oral health-related quality of life was assessed by means of questionnaires. RESULTS: A mean bone loss of 1.04 mm on the mesial and distal sides was recorded during the 18-month period after loading of the implants. The score for general satisfaction level was 95.67 ± 5.68. Similarly high VAS scores were given by the patients in all other specific items on patient satisfaction. The total score for the Oral Health Impact Profile-20 (OHIP-20) was 34.07 ± 13.90, which was comparable to that recorded in other studies. CONCLUSION: The short-term radiographic peri-implant bone level changes of MDIs immediately loaded with overdentures in the edentulous mandible were within the physiologic limits. The patients expressed a high level of satisfaction and oral health-related quality of life with this treatment modality.

Maxillary Complete Denture Outcomes: A Systematic Review of Patient-Based Outcomes.

PURPOSE: The aim of this systematic review is to report on the current knowledge regarding patient satisfaction as a primary outcome for maxillary complete denture therapy. We asked, "For the maxillary edentulous patient treated using maxillary dentures, what are the patient-based outcomes regarding quality of life and treatment satisfaction." MATERIALS AND METHODS: An electronic search of publications up to March 2014 was established using four databases: PubMed, Web of Science, Scopus, and Embase. To meet the ultimate goal of establishing clinical guidelines based on available information, prospective comparative studies, cohort prospective studies, and retrospective studies on more than 10 subjects were included. The electronic search identified 4,530 articles that were evaluated at the title, abstract, and article level to include 31 articles of interest. The patient-based outcomes and satisfaction data included were examined and reported. RESULTS: The studies included 5,485 participants. Of these, 2,685 were identified as wearing maxillary complete dentures. Reported mean ages ranged from 59.7 to 73.6 years. A systematic review indicated that the provision of new maxillary complete dentures for edentulous patients results in improved self-reported satisfaction and oral health-related quality of life. The included reports, while providing evidence that complete denture satisfaction of participants and new dentures improve self-reported outcomes, did not include variables that influence these positive outcomes. CONCLUSION: A broad range of evidence supports the use of complete dentures for rehabilitation of the edentulous maxilla. When considering treatment of the edentulous maxilla, the expectations of patients for esthetic and phonetic (social) rehabilitation are high and can be met using maxillary complete dentures as the mode of prosthetic rehabilitation. Patients dissatisfied with new complete dentures may be referred for dental implant therapies involving fixed or removable prostheses.

Effect of dentist's clinical experience on treatment satisfaction of a complete denture.

The relationship between the prosthodontic experience of dentists and satisfaction of complete denture wearers remains unknown. To investigate whether a prosthodontist's clinical experience affects treatment satisfaction of a complete denture wearer. From April 2004 to July 2006, we conducted a randomised controlled trial at two centres, including 74 edentulous patients; of these, 32 and 30 were randomly allocated to the ED or ID group, respectively. All the patients rated their satisfaction with dentures, including general satisfaction and satisfaction of chewing ability, speaking, cleaning, stability, retention, comfort and aesthetics. These satisfaction ratings were measured by a 100-mm visual analog scale (VAS). Perceived chewing ability to foods, divided into five grades, was measured using a questionnaire. The mastication index (MI) was calculated for each grade. General satisfaction and satisfaction of speaking, stability and retention were significantly higher in the ED than in the ID group (P = 0·049, 0·003, 0·019 and 0·041, respectively). No significant difference existed between the MI of the ED (71·3 ± 18·4) and ID group (64·1 ± 16·53). However, the perceived chewing ability of grade 5 food, whose texture was the hardest among all the grades, was significantly higher in the ED group than in the ID group. Within its limitations, this study showed that a clinician's prosthodontic experience affects a complete denture wearer's satisfaction ratings.

The quality of removable prostheses in dentate, community-dwelling elderly residing in Puerto Rico.

PURPOSE: Edentulism has been decreasing in the US elderly population; however, due to the increasing number of elderly, the need for prostheses has been projected to rise over the next several decades. One of the aims of the Puerto Rican Elderly Dental Health Study (PREDHS) was to assess the quality of removable prostheses (RP) in the Puerto Rican (PR) elderly (>69 years of age) population. METHODS: A cross-sectional design, using a subgroup from the Puerto Rican Elderly: Health Conditions (PREHCO) study of dentate, community-dwelling older adults from the greater San Juan area was employed. Eligible participants were administered structured questionnaires and examined in their homes by three trained and calibrated dentists using National Institute of Dental and Craniofacial Research (NIDCR) criteria. RESULTS: One hundred and eighty three (183) participants were examined (61 males, 122 females) (p < 0.001). Overall, 64% were found to have a prosthetic problem with no statistical difference between genders. Unadjusted and age-adjusted logistic models were employed. Increasing age was associated with both upper and lower clinically defined abraded prostheses, (p = 0.007; p = 0.041, respectively). Maxillary (23%) and mandibular (27%) prostheses needed replacement due to deficiencies. CONCLUSION: RP deficiencies were found in almost two-thirds of a representative sample of dentate 70+ year-old people residing in PR. There was no difference in the proportion of deficiencies between elderly who reported a dental visit in the preceding year or not having seen a dentist. A quarter of the prostheses required replacement. The findings from this and the NHANES studies demonstrate that an engaged and recognized prosthodontic dental school faculty continues to be as important now as it was a generation ago.

The influence of master cast technique on the cast precision of implant-retained fixed prostheses.

The aim of this study was to evaluate the precision of three different mold filling techniques in order to obtain a cast simulating a three-unit, implant-retained, fixed prosthesis. Thirty casts (n = 10) were obtained using three different mold filling techniques. Group 1 used a unique fulfillment technique, Group 2 used a two-step fulfillment technique, and Group 3 used a latex cylinder technique. Using a metallic matrix, a titanium substructure was created to simulate a three-unit fixed prosthesis used as reference to evaluate the marginal misfit and tension forces in each cast. The vertical misfit was measured by an optical microscope with an increase of 120X and by an analysis unit using the one-screw test. The tension was quantified using strain gauges. The strain results showed a statistical difference between Group 3 and the other groups. The Tukey test showed no difference between the different treatment groups (p = 0.05). All three techniques were deemed efficient; however, considering that the cylinder latex technique induced less force toward the implants, it is the preferable technique for daily clinical practice.

[Complete removable dentures: a commitment to best efforts]. / Volledige gebitsprothesen: een inspannings-verbintenis!

The provision of complete removable dentures can, in legal terms, be defined as a commitment to perform the best of one's abilities. Indeed, the result or patient's satisfaction with the new dentures, is difficult to predict and is apparently not only dependent upon the dentist/denturist and variations in materials and techniques. The relationship between the dentist/denturist and the patient is complex, but influences to a large extent patient satisfaction. This is especially true in cases of patients with reduced residual alveolar ridges or other (oral) problems. When a complete removable denture is being prepared, the patient should be thought of as the dentist/denturists most reliable contributor. By way of preventing or preparing for possible legal procedures, a good patient record is of importance. The patient record should contain the information which the patient has provided, the patient's request for help, and the character of the patient's expectations for treatment.

A methodology to study the effects of prosthesis misfit over time: an in vivo model.

PURPOSE: Passive fit of implant-supported superstructures cannot currently be achieved. The aim of this investigation was to create a methodology that can be used to study the effects of prosthesis misfit in humans. MATERIALS AND METHODS: An edentulous patient received two interforaminal implants and a screw-retained bar for the retention of the mandibular denture. A corresponding in vitro model with strain gauges placed mesially and distally, adjacent to the implants, was fabricated to serve as a standardizing control. Over a period of 6 months, a total of 10 measurements on both the in vitro model and in the patient's mouth were conducted with newly fixed strain gauges on the bar. RESULTS: The in vitro experiments showed that no component wear at the abutment-bar interface had occurred and that repositioning of the strain gauges on the bar caused deviations in strain measurements up to 10.55%. In vivo, a reduction in strain development, from 445 to 383 Mum/m, was observed in the initial phase up to 12 weeks after bar insertion. Subsequently, the measurement values increased, and after a period of 24 weeks, they nearly reached the initial strain level (443 microm/m). Only minor changes in strain development of the bar could be detected; these might be a result of limited dynamic loading and the cortical architecture of the surrounding bone. Deviations in measurement accuracy caused by repositioning of the bar strain gauge are a limitation of this technique and should be eliminated in future studies. CONCLUSIONS: The present methodology can be applied to study changes in static implant loading over time in humans.

Marginal fit of 14-unit zirconia fixed dental prosthesis retainers.

The marginal fit of 14-unit fixed dental prosthesis retainers and single-crown copings fabricated by the same computer-aided design (CAD)/computer-aided manufacturing (CAM) system were evaluated in vitro hypothesizing that the marginal opening might be independent of the type of restoration. Eight ivorine maxillary teeth (FDI locations 27, 25, 23, 21, 11, 13, 15 and 17) were prepared to accommodate a 14-unit prosthesis. Ten fixed dental prosthesis retainers and 40 single-crown-copings were fabricated using Zeno CAD/CAM on 20 master dies. Four cross-sections were made from each tooth and the marginal gap dimensions were measured. One-way anova was used to test the difference between the experimental groups and two-way anova and a post hoc test (Student-Newman-Keuls) were carried out to determine the influence of the location of the abutment tooth and the measurement location within the abutment tooth in the experimental groups (P < 0.05). Mean marginal gap dimensions and standard deviations for fixed dental prosthesis retainers and single-crown copings were 25 +/- 29 and 13 +/- 12 microm, respectively. The type of restoration showed a significant influence (P < 0.001) on the marginal gap. The location of the abutment tooth (P < 0.001) and the measurement location (P < 0.001) exhibited significant influence on marginal gaps of fixed dental prosthesis retainers while no influence on single-crown copings could be detected. The highest marginal gaps were found at the palatal surface of the incisor and canine of the 14-unit fixed dental prosthesis retainers. Fourteen-unit fixed dental prosthesis showed significantly higher marginal openings than single crowns fabricated under the same conditions. However, both restorations showed clinically acceptable marginal openings.

In vivo qualitative analysis of the biocompatibility of different cyanoacrylate-based adhesives.

Cyanocrylates have been widely used in the medical and dental fields for several years. In Dentistry, cyanoacrylates have been used for suturing, pulp capping, as retrofilling material in endodontic surgeries, and as cervical plug for pulpless teeth bleaching. The biocompatibility of these adhesives has been the topic of many researches and subcutaneous implantation is an effective methodology for these studies. The present study evaluated the biocompatibility of three different cyanoacrylate-based adhesives. Thirty-six Wistar rats were used, divided into four groups of 9 animals each: A (control)--distilled water, B--cyanoacrylate ester (Super Bonder), C - n-butyl-cyanoacrylate (Histoacryl) and D--alpha-cyanoacrylate (Three Bond). The materials were dispensed in sponges of polyvinyl chloride, the animals were incised and the sponges were inserted in the subcutaneous tissue and sutured. Each group was sub-divided according to the time of sacrifice of the animals: 7, 21 and 45 days. Subjective analysis of the histologic material showed that all groups presented some degree of irritability, but the inflammatory reaction decreased with the experimental time in all groups. Group D showed an inflammatory reaction which was closer to that of the control group and was considered to have good biocompatibility. Groups B and C were similar and presented more aggressive inflammatory reactions when compared to the control group. Based on the results, it was concluded that alpha-cyanoacrylate (Three Bond) was the most biocompatible adhesive because it caused the lowest levels of inflammation.

In vivo qualitative analysis of the biocompatibility of different cyanoacrylate-based adhesives

Cyanocrylates have been widely used in the medical and dental fields for several years. In Dentistry, cyanoacrylates have been used for suturing, pulp capping, as retrofilling material in endodontic surgeries, and as cervical plug for pulpless teeth bleaching. The biocompatibility of these adhesives has been the topic of many researches and subcutaneous implantation is an effective methodology for these studies. The present study evaluated the biocompatibility of three different cyanoacrylate-based adhesives. Thirty-six Wistar rats were used, divided into four groups of 9 animals each: A (control) - distilled water, B - cyanoacrylate ester (Super Bonder), C - n-butyl-cyanoacrylate (Histoacryl) and D - alpha-cyanoacrylate (Three Bond). The materials were dispensed in sponges of polyvinyl chloride, the animals were incised and the sponges were inserted in the subcutaneous tissue and sutured. Each group was sub-divided according to the time of sacrifice of the animals: 7, 21 and 45 days. Subjective analysis of the histologic material showed that all groups presented some degree of irritability, but the inflammatory reaction decreased with the experimental time in all groups. Group D showed an inflammatory reaction which was closer to that of the control group and was considered to have good biocompatibility. Groups B and C were similar and presented more aggressive inflammatory reactions when compared to the control group. Based on the results, it was concluded that alpha-cyanoacrylate (Three Bond) was the most biocompatible adhesive because it caused the lowest levels of inflammation.

Is there a certain number of implants needed to retain an overdenture?

The aim of this systematic review was to determine if there are reasons to recommend a certain number of implants for retaining or supporting maxillary or mandibular overdentures. Literature search for this review covered clinical trials, randomized controlled-clinical trials, meta-analyses and review articles in English dental journals from 1990 to 2007. The search produced 1779 articles, of which the abstracts of 182 studies were reviewed and those with any exclusion criterion were removed. The remaining 39 full articles were reviewed against the inclusion criteria for finalizing the selection. Eleven research reports meeting the inclusion criteria were selected for this review; three for the maxilla and eight for the mandible. According to this data, in the maxilla and in the mandible, patient satisfaction or function of the prosthesis are not dependent on the number of implants or type of attachment. In the mandible, an overdenture with two implants and with bar attachment has the least number of complications.

A quality assessment of the casting process on magnetic keepers.

PURPOSE: The objective of this study was to qualitatively investigate the effect of the burn-out (mold) temperature, investment material, and casting alloy on the surface integrity of the Magfit EX keeper. MATERIALS AND METHODS: Forty-two Magfit EX keepers were waxed-up, invested in five investment materials (Beauty-Cast, Cristobalite, CM-10, Cera-Fina, Castorit-super), and subjected to burn-out temperatures ranging from 450 to 700 degrees C at intervals of 50 degrees C. The keeper samples were then cast into copings with three alloys (Castwell, Protor 3, Optimum) under standard conditions. The keeper surfaces were then examined under a microscope, and the compositions were assessed by an X-ray micro-analyzer in a scanning electron microscope (SEM). A new keeper served as control. RESULTS: At a burn-out temperature of 550 degrees C, the keeper surface started to disintegrate. X-ray micro-analysis showed an increase in oxygen content with increasing temperature. At 700 degrees C, the keeper surface disintegrated, and the composition differed markedly from that of the new keeper. The keeper surfaces were intact with all investments except those with Beauty-Cast. The keeper surfaces were found to be damaged when the casting alloy was Optimum. CONCLUSIONS: Beauty-Cast investment with a burn-out temperature of 700 degrees C is unsuitable for casting the Magfit EX keeper-coping unit. Also, high fusing alloys are not recommended for casting Magfit EX keepers.

Treatment with removable partial dentures: a longitudinal study. Part II.

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%.

Clinical quality of removable dentures provided by dentists, denturists and laboratory technicians.

The aim of this study was to evaluate the clinical quality of removable dentures of elderly Finnish men, which had been prepared either by dentists, denturists or dental laboratory technicians. The participants comprised 242 denture-wearing subjects, with 231 maxillary and 177 mandibular removable dentures which had been prepared either by dentists, denturists or dental laboratory technicians. Clinical examinations were carried out without the examining dentist knowing who had provided the dentures. Complete dentures which had been illegally provided by laboratory technicians had significantly poorer retention and fitted less well in tuber and alveolar areas than those provided by either dentists or denturists. Complete maxillary dentures which had been provided illegally by laboratory technicians had significantly (P < 0.01) higher occurrence (90%) of some unacceptable characteristics than those (43%) provided by dentists or denturists. The difference between complete mandibular dentures was also obvious, 86% versus 59%, although statistically non-significant. Of those partial maxillary dentures provided by dentists 53% had some unacceptable characteristics, compared with 80% of those illegally provided by denturists or laboratory technicians (NS). In the case of partial mandibular dentures, 36% of those provided by dentists and 32% of those by denturists or laboratory technicians had some unacceptable characteristic (NS). Illegal provision of removable dentures seemed to be related to decreased clinical quality.

Agreement between clinical measures of quality and patients' rating of fit of existing and new complete dentures.

OBJECTIVES: To assess agreement between patients' appreciation of fit and clinical assessment of quality of existing and new complete dentures. MATERIALS AND METHODS: In each case existing complete dentures at the initial visit and new complete dentures at the first post insertion visit were assessed by a prosthodontist using a validated method for assessing denture quality. Patients rated fit of existing and new complete dentures on four-point scales. Weighted Cohen's kappa and multiple correspondence analyses were the statistical methods employed in this study. RESULTS: 459 patients completed the study. A statistically "fair" level of agreement was found between clinical and patient assessment of dentures. There was close correspondence between dentist and patient appreciation when the existing dentures were rated as poor and when the new dentures were rated highly. DISCUSSION: A worthwhile level of agreement between patients' appreciation of fit of complete dentures and the clinical assessment of quality of existing and new complete dentures was found. Marked differences in the nature of agreement for patients' and clinicians' rating of new and existing dentures were demonstrated. These results emphasize the importance of denture quality in achieving patient approval. CONCLUSION: Agreement and correspondence between patient and clinician appreciation of existing and new complete dentures were determined.