The International Journal of Prosthodontics, 04/2007

A 53-year-old male with a long history of gastric distress seeks dental treatment to restore function and esthetics. He complains of inadequate dentures and tooth sensitivity. He hopes that a solution to his dental problems will also address his gastric problems.

A 62-year-old female with a history of osteoporosis and temporomandibular disorder (TMD) seeks dental treatment to address her masticatory concerns. Her occlusion is characterized by a Kennedy Class I situation in the mandible, and a completely restored failing long-span fixed partial denture (FPD) in the maxilla.

Purpose: The aim of this prospective clinical cohort study was to determine the success rate of 3- to 5-unit zirconia frameworks for posterior fixed partial dentures (FPDs) after 5 years of clinical observation. Materials and Methods: Forty-five patients who needed at least 1 FPD to replace 1 to 3 posterior teeth were included in the study. Fifty-seven 3- to 5-unit FPDs with zirconia frameworks were cemented with 1 of 2 resin cements (Variolink or Panavia TC). The following parameters were evaluated at baseline, after 6 months, and 1 to 5 years after cementation at test (abutments) and control (contralateral) teeth: probing pocket depth, probing attachment level, Plaque Index, bleeding on probing, and tooth vitality. Intraoral radiographs of the FPDs were taken. Statistical analysis was performed using descriptive statistics, Kaplan-Meier survival analysis, and the McNemar test. Results: Twenty-seven patients with 33 zirconia FPDs were examined after a mean observation period of 53.4 ± 13 months. Eleven patients with 17 FPDs were lost to follow-up. After the 3-year recall visit, 7 FPDs in 7 patients were replaced because they were not clinically acceptable due to biologic or technical complications. After 5 years of clinical observation, 12 FPDs in 12 patients had to be replaced. One 5-unit FPD fractured as a result of trauma after 38 months. The success rate of the zirconia frameworks was 97.8%; however, the survival rate was 73.9% due to other complications. Secondary caries was found in 21.7% of the FPDs, and chipping of the veneering ceramic in 15.2%. There were no significant differences between the periodontal parameters of the test and control teeth. Conclusions: Zirconia offers sufficient stability as a framework material for 3- and 4-unit posterior FPDs. The fit of the frameworks and veneering ceramics, however, should be improved

Purpose: This study aimed to prospectively analyze the outcomes of 304 feldspathic porcelain veneers prepared by the same operator, in 100 patients, that were in situ for up to 16 years. Materials and Methods: A total of 304 porcelain veneers on incisors, canines, and premolars in 100 patients completed by one prosthodontist between 1988 and 2003 were sequentially included. Preparations were designed with chamfer margins, incisal reduction, and palatal overlap. At least 80% of each preparation was in enamel. Feldspathic porcelain veneers from refractory dies were etched (hydrofluoric acid), silanated, and cemented (Vision 2, Mirage Dental Systems). Outcomes were expressed as percentages (success, survival, unknown, dead, repair, failure). The results were statistically analyzed using the chi-square test and Kaplan-Meier survival estimation. Statistical significance was set at P < .05. Results: The cumulative survival for veneers was 96% ± 1% at 5 to 6 years, 93% ± 2% at 10 to 11 years, 91% ± 3% at 12 to 13 years, and 73% ± 16% at 15 to 16 years. The marked drop in survival between 13 and 16 years was the result of the death of 1 patient and the low number of veneers in that period. The cumulative survival was greater when different statistical methods were employed. Sixteen veneers in 14 patients failed. Failed veneers were associated with esthetics (31%), mechanical complications (31%), periodontal support (12.5%), loss of retention > 2 (12.5%), caries (6%), and tooth fracture (6%). Statistically significantly fewer veneers survived as the time in situ increased. Conclusions: Feldspathic porcelain veneers, when bonded to enamel substrate, offer a predictable long-term restoration with a low failure rate. The statistical methods used to calculate the cumulative survival can markedly affect the apparent outcome and thus should be clearly defined in outcome studies

Purpose: To determine the location of mucosal injuries that appear following placement of complete dentures, as well as the number of adjustments necessary to achieve patient comfort. The frequency of mucosal injuries in female and male patients and their connection with clinical anatomic features were also investigated. Materials and Methods: Sixty-one completely edentulous healthy patients who wore dentures (47 women and 14 men) took part in the study; 122 newly fabricated complete maxillary and mandibular dentures were investigated. All patients were seen for a 1-week adjustment appointment. Areas where signs of denture-induced mucosal injuries appeared were marked on an anatomic illustration. The follow-up period was in 1-week increments as deemed necessary by the patient. Associations between variables were analyzed with analysis of variance. Results were recorded as mean ± SD. Statistical significance was set at P £ .05. Results: Eighty-seven percent of the dentures required adjustment at week 1, 50% at week 2, and only 7% at week 3. No patients required a further visit. Most frequently injured maxillary areas were the vestibular sulcus (41%), maxillary tuberosity (21%), and hamular notch (12%). In the mandible, the most frequently injured areas were the retromylohyoid area (17%), lingual sulcus (14%), and vestibular sulcus (13%). Denture-induced irritations were detected in a higher ratio in the mandible (P < .001), especially in male denture wearers at the first adjustment (P < .05). Men had a higher ratio of lesions at the region of the maxillary vestibular sulcus between the labial and buccal frenum and at the mandibular vestibular sulcus of the buccal shelf region (P < .001). Conclusions: Denture-induced irritations appeared most often in the vestibular sulcus of the maxilla and mandible, indicating that it is necessary to evaluate the area of the facial seal of the prosthesis by applying a medium- or a heavy-pressure indicator paste to the borders, and to make adjustments at the delivery stage and subsequent adjustment appointments. Denture placement must not be the final patient-clinician encounter when treating with complete dentures. Denture adjustments are very important clinical phases of denture fabrication and essential in patient care

This study aimed to examine the influence of osseointegrated implants on decision making for prosthodontic treatments. Twenty-five randomly selected Japanese dental clinicians in 1995 and 2005 with 5 to 15 years of clinical experience were requested to define bone support levels for prosthodontic treatment options. Comparison of the results expressed with the fuzzy function between 1995 and 2000 showed that indications for extraction have expanded with the prevalence of osseointegration concepts. Further, the definition of poor bone quality has changed. Osseointegration has influenced the decision-making process in prosthodontic treatments related to extraction.

The purpose of this study was to determine the effect of oral moisturizing agents, denture adhesives, and surface treatments on the retention of an acrylic resin test base dislodged from the maxillary alveolar ridges of xerostomic radiotherapy patients. Acrylic resin test bases prepared for 10 edentulous xerostomia patients were subjected to 8 surface treatment methods: method 1 = untreated dry surface; method 2 = use of Biotène oral moisturizer; method 3 = use of Protefix denture adhesive; method 4 = combination of Biotène and Protefix; method 5 = sandblasting of test bases; method 6 = use of Biotène on sandblasted surface; method 7 = use of Protefix on sandblasted surface; method 8 = combination of Protefix and Biotène on sandblasted surface. After each treatment, a tensile testing apparatus was used to dislodge the inserted test bases, and force values (N) were recorded. A significant difference in retentive force was observed between the 4 Protefix groups and those that did not use denture adhesive (P < .001). There were no differences among the 4 combinations of denture adhesive treatments (P > .05). Sandblasting the denture surfaces did not increase retentive forces alone or in combination with any other treatments. Biotène oral moisturizing agent was used in 4 treatment methods, but only had a significant effect on increasing retentive force when used with a nonsandblasted surface (P < .05). Biotène had no effect on retentive force compared to a nonsandblasted surface without moisturizer or when it was used in combination with any other methods. Protefix denture adhesive offered the greatest improvement in retentive force. Sandblasting the intaglio surface did not improve retentive force. Biotène was reported to improve patient comfort but had minimal effect on retentive force; however, Biotène can be assumed to be a more advantageous method of increasing retention compared to sandblasting (P < .05).

Purpose: The purpose of this study was to characterize a population of oligodontia patients and identify patterns of tooth agenesis. Materials and Methods: A total of 116 patients with nonsyndromic oligodontia were studied, and the Tooth Agenesis Code (TAC) per quadrant was calculated. Oligodontia was defined as the congenital absence of 6 or more permanent teeth, excluding the third molars. The TAC is a unique number, consistent with a specific pattern of tooth agenesis. The authors suggest the use of an overall TAC with which the dentition throughout the mouth can be presented by a single number. Frequency analysis was used to study the prevalence of various patterns. Results: There was a great diversity of TACs. In the maxilla, agenesis of both premolars and the lateral incisor or the presence of only the central incisor and first molar were the most common patterns. In the mandible, agenesis of the second premolar or both premolars occurred most frequently. Conclusions: No single pattern of agenesis occurred more than twice when the full mouth was viewed. Hence, the presentation of the dentition in oligodontia is very heterogeneous. Evaluation of treatment strategies in oligodontia patients is a methodologic challenge because homogenous, comparable subgroups of patients are not available.

This study aimed to evaluate the performance of visual and spectrophotometric tooth shade analysis. Two operators independently selected the best match of 3,758 anterior teeth of 106 patients at 3 different dates, using the Chromascop-Complete shade guide. Additionally, tooth color was analyzed 3 consecutive times using a reflectance spectrophotometer. Spectrophotometry showed high agreement values (89.6%); both examiners agreed in 49.7% of the measurements. Visual assessment resulted in significantly darker ratings than spectrophotometry (P < .0005). However, a positive association was observed for both procedures (P = .548). Spectrophotometric shade determination seems to be significantly more reproducible than the visual procedure.

This study evaluated the shear bond strength of a newly developed resin bonding system, including single-liquid ceramic primer and dual-cured resin luting agent, to 5 ceramic materials (feldspathic porcelain, machinable ceramic, In-Ceram Alumina, Procera AllCeram alumina, and Cercon). Ceramic specimens were cleaned with phosphoric acid, treated with primer, and bonded with a resin luting agent. Shear bond strength was determined after 24 hours of immersion in water and/or 10,000 thermocycles. There were no significant differences in bond strength before and after thermocycling for the 5 ceramic materials (P > .05). The findings indicate that the resin bonding system may offer an acceptable performance in terms of clinical success for the 5 ceramic restorations.

This study aimed to evaluate the effect of surface glazing and polishing of yttrium-stabilized tetragonal zirconia polycrystal ceramic on early dental biofilm formation, as well as the effect of brushing on the removal of adhered bacteria. Two subjects used oral appliances with polished and glazed samples fixed to the right and left sides. After 20 minutes, 1 hour, and 6 hours, the subjects manually brushed the samples on the right side. The samples were analyzed using scanning electron microscopy. Granular material was verified on the samples, especially on irregular surfaces. After 1 hour, there was no significant difference between glazed and polished surfaces in terms of bacterial presence. However, glazed surfaces tended to accumulate more biofilm, and brushing did not completely remove the biofilm. Polished surfaces seem to present a lower tendency for biofilm formation.

Purpose: To define the normative ranges of the Current Perception Threshold (CPT) of the palatal mucosa and to correlate it with the subjects' attributes. Materials and Methods: A group of 129 informed healthy subjects consented to participate in the study. A Neurometer NS3000 device was used to evaluate the CPTs of the nasopalatine nerve (NPN) and the greater palatine nerve (GPN) by using 2,000-, 250-, and 5-Hz stimulations. After confirming the relationships with regard to gender, age, weight, height, alcohol consumption, duration of sleep, weight percentage of water content, smoking, and CPT, the normative ranges of the CPT measurements were obtained. Results: Correlations were observed between age and CPTs obtained with the 2,000- and 250-Hz stimulations of the GPN. The CPTs of the GPN were higher than those of the NPN. With the exception of the 5-Hz stimulation of the NPN, the CPTs in men were higher than those in women; however, the within- and between-site ratios exhibited no differences between the male and female subjects. No significant effects of smoking and alcohol consumption on CPT were observed. Range analysis revealed an increase in the CPTs as the frequency increased from 5 to 250 to 2,000 Hz. Within-site ratio analysis revealed increasing and spreading CPT ratios in the following order: 250/5 Hz, 2,000/250 Hz, and 2,000/5 Hz. In the order of 5-, 250-, and 2,000-Hz stimulations, decreasing ratios were observed for the between-site ratio analysis. Conclusion: This study provides useful diagnostic criteria for CPTs in the palatal mucosa.

The aim of this prospective long-term clinical trial was to verify the clinical success of prefabricated precision attachments with regard to periodontal condition, wearing comfort, and stability of attachment friction. Twenty-eight patients were fitted with 35 prostheses with Swiss Mini-SG precision attachments. Following clinical investigation and monitoring over a 3-year period, 80% of the prostheses were functioning well. The average pocket depth of the abutment teeth at the buccal sites and the periodontal parameters Approximal Plaque Index and Sulcus Bleeding Index showed statistically significant improvements. The abutment tooth mobility (Periotest measurements) decreased. It is not advisable to support the attachments on single abutment teeth.