The International Journal of Prosthodontics, 06/2016

Purpose: The aim of this study was to report long-term clinical survival of single implants provided with turned and moderately rough surfaces in routine practice. Materials and Methods: All patients consecutively treated at a specialist center with single-crown implants from 1982 to 2013 were included. For all these patients, data on implant failure and last examination at the clinic were collected, and thereafter cumulative survival rates (CSR) were calculated for patients treated in the maxilla or mandible with turned or moderately rough surfaces, respectively. Results: In total, 2,417 patients (2,665 operations) were treated with 3,211 single implants during the inclusion period (31 years). Of these, 573 (615 operations, 754 implants) were followed up for at least 10 years. Overall proportions of patients followed up for 5 years up to 25 years decreased from 68.2% to 37.0% of treated patients. A higher follow-up compliance was observed for patients treated during the earlier period of inclusion. Patient CSR for 15 and 10 years for maxillary implant placement was 95.8% for turned surfaces and 98.5% for moderately rough surfaces, respectively. Corresponding patient CSR for 10 and 25 years for mandibles was 95.1% and 97.2%, respectively. No implant was reported as a failure after 10 years of follow-up. Conclusion: A significant number of patients can be expected to be lost to followup during long-term periods in routine practice. Single-implant treatment is an overall predictable treatment procedure over the long term, with a lower failure rate for implants with a moderately rough surface placed in the maxilla. This difference seems to be established already during the early phase of osseointegration.

This article describes the use of a newly invented compound stick gun to take impressions for complete denture. The border molding process involves loading the modeling compound in an electric heating device and applying an even thickness of compound on the flange of a custom tray at a proper temperature without hot water tempering. This method provides a quicker and easier border molding process alternative to conventional techniques.

Purpose: The aim of this study was to investigate associations between objectively and subjectively measured masticatory function and oral health-related quality of life (OHRQoL) in partial maxillectomy patients wearing dentomaxillary prostheses. Materials and Methods: A sample of 32 consecutively treated patients who had undergone a partial maxillectomy were enrolled. Masticatory function was assessed using two objective measures and one subjective measure. The objective measures were masticatory performance (MP), which was estimated by measuring the glucose extracted from gummy jelly, and food mixing ability (a*), which was assessed using color-changeable chewing gum. The subjective measure was perceived chewing ability, rated as masticatory score (MS) based on the patient's responses to a food intake questionnaire. OHRQoL was assessed using the Geriatric Oral Health Assessment Index (GOHAI). Relationships between the masticatory function measures and OHRQoL were analyzed using Spearman rank correlation coefficient. Results: The correlation coefficients (r) obtained were 0.57 (P = .001) for MS and GOHAI, 0.247 (P = .173) for MP and GOHAI, −0.173 (P = .343) for a* and GOHAI, 0.517 (P = .002) for MP and a*, 0.199 (P = .257) for MP and MS, and 0.019 (P = .919) for a* and MS. Conclusion: Subjective MS showed a significant positive correlation with GOHAI score, suggesting that perceived chewing ability could be an important factor in the estimation of OHRQoL in partial maxillectomy patients.

Purpose: The aim of this study was to determine endodontic treatment needs and types of endodontic disease following fixed prosthodontic treatment 24 hours after tooth preparation, 1 week after tooth preparation, 1 month after placement, and 6 months after placement. Materials and Methods: Study groups consisted of patients who attended a university dental hospital department of prosthodontics for fixed prosthodontic treatment from January 2011 to December 2013. All teeth were clinically and radiographically evaluated according to American Association of Endodontists evaluation criteria before preparation. Metal-ceramic fixed partial dentures were placed for all patients. A total of 1,633 abutment teeth were prepared with 1,100 pontics in 524 patients (214 female and 310 male). Participant age, sex, and tooth number were recorded. Endodontic treatment follow-up was scheduled for 24 hours after tooth preparation, 1 week after preparation, 1 month after placement, and 6 months after placement, and all teeth were evaluated after placement of FPDs according to a modified criteria. Results: 2,733 retainers were placed with 624 FPDs. Of the FPDs, 332 (53%) were placed in the posterior and 196 (31.5%) in the anterior region. The remaining 96 FPDs (15.5%) were placed anteroposterior. The abutment/pontic ratio was 1.44:1. The number of retainers per FPD was 4.37. Of 1,633 abutment teeth, 103 were endodontically treated after placement of FPDs. Most observed endodontic disease was symptomatic irreversible pulpitis. There were statistically significant differences in terms of teeth regions (P < .001). When follow-up times of 24 hours, 1 week, 1 month, and 6 months were evaluated, there was no statistically significant difference among all teeth groups (P > .05). Conclusion: A total of 2,733 retainers on 624 FPDs were evaluated over 6 months, and the mean endodontic treatment need ratio was 6.3%.

Purpose: The aim of this study was to evaluate the improvement in mandibular complete dentures (MCD) stability using a modified neutral zone technique (MNZT). Materials and Methods: For 21 patients who were dissatisfied with their primary MCD, MCDs were fabricated using the MNZT. Results: Nearly all of the patients showed considerable improvement in oral health-related quality of life, and 85.7% of the patients stated an improvement in general denture stability and while chewing. A masticatory function test showed no significant changes. Conclusion: This MNZT seems to improve MCD function, especially in patients who cannot be treated with implants.

Purpose: The objective of this clinical study was to determine the relationship of mandibular morphology with residual ridge resorption (RRR) of implant-retained overdenture (IRO) patients. Materials and Methods: RRR was quantified as change in bone volume over 1- and 2-year periods using cone beam computed tomography and a medical imaging program. Features of the mandibular morphology, namely the gonial angle, ramus length, ramus width, corpus length, and corpus height, were measured on three-dimensional models and correlated to the RRR. A total of 25 participants were treated with mandibular IROs opposing maxillary complete dentures. By the 2-year follow-up, radiographic data for 18 patients were complete for analysis. Of these 18 participants, half fall into the low gonial angle category and the other half into the high angle. Results: The extent of RRR was highly variable among participants and ranged from −2 to +2 mm in depth over the 2-year period. The mean decrease in bone volume after the first year was 3.8 ± 4.5%. This rate decreased to 3.2 ± 4.1% after the second year. RRR occurs either by translation of the entire thickness of cortical layer apically or by thinning of the outer cortical layer. RRR was significantly correlated to gonial angle (r = .471; P = .048) and predominantly occurred in the molar region in low-angle participants and more anteriorly in high-angle participants. There was no association between RRR and ramus length (r = −.341; P = .166), ramus width (r = −.183; P =.468), corpus length (r = .057; P = .821), and corpus height (r = .097; P = .702). Conclusion: Within the limitations of this study, it may be concluded that gonial angle is significantly related to RRR associated with IROs.

This study retrieved and analyzed by scanning electron microscopy (SEM) and energydispersive x-ray spectroscopy (EDS) the failure of a single four-unit fixed partial denture (FPD). Low SEM magnifications revealed a smooth/featureless fracture surface, indicating brittle fracture. Higher magnifications revealed a small fatigue fracture region located on the inferior part of the connector. EDS analysis indicated that the FPD alloy was gold-based. Additionally, SEM showed segregation of small spherical particles at grain boundaries of the alloy, with high aluminum and oxygen content. The particles, most likely retained aluminum, possibly resulted from sandblasting procedures for a scrap metal alloy, which was then recast into a new FPD. It appears that the fracture was initiated in the oral cavity by fatigue crack formation, but the presence of Al2O3 particles facilitated alloy embrittlement and brittle fracture.

Purpose: The aim of this study was to compare the 5-year outcome of immediate loading with that of conventional loading for anterior single-tooth implants placed in healed sites. It was hypothesized that immediate loading is not inferior to conventional loading. Materials and Methods: A total of 62 patients with a missing maxillary anterior tooth were included. At random, patients were treated with an implant that was restored either with a nonoccluding temporary crown within 24 hours after implant placement (immediate group) or according to a two-stage procedure after 3 months (conventional group). All implants were placed in healed sites. Follow-up visits were performed after definitive crown delivery and 1 and 5 years thereafter. Outcome measures were radiographic marginal bone level changes, implant survival, complications, soft tissue aspects (probing depth, plaque, bleeding, soft tissue level changes), esthetic outcome, and patient satisfaction. Results: Three patients in each study group were lost to follow-up. No significant differences were found in terms of marginal bone loss (1.16 ± 0.93 mm in the immediate group and 1.20 ± 1.10 mm in the conventional group), survival (one implant lost in the immediate group), complications, soft tissue aspects, esthetic outcome, and patient satisfaction. Conclusion: For anterior single-tooth implants placed in healed sites, the outcome of immediate loading is not inferior to conventional loading.

This case report describes the reproduction of the current obturator of a frail elderly patient using the digitization concept. A computed tomography scanner was used to scan the obturator. The virtual model was created using three-dimensional modeling software. The model was printed using a plastic with a low melting point with a fused deposition modeling technique in a threedimensional printer and then conventionally processed. The definitive obturator was inserted and evaluated for fit, function, and esthetics and was successfully delivered at the second visit. The patient was satisfied with the oral function and esthetics of the reproduced obturator. This case report confirms the effectiveness of digitization in the reproduction of an obturator that enabled satisfactory oral function and esthetics.

Purpose: To investigate the influence of framework materials with different elasticity moduli on the biomechanical performance of fixed partial dentures (FPDs). Materials and Methods: A tooth-anchored three-unit FPD and surrounding tissues were modeled in two variants (veneered/ full anatomical FPD) and loaded on the central unit. Three different framework materials (titanium, zirconia, high-performance polymer) were simulated. Results: The polymer framework resulted in reduced framework stresses and increased veneering stresses. Varying the framework material had minimal influence on the loading of surrounding tissue. Conclusions: Using soft, novel materials as framework for dental FPDs does not negatively influence biomechanical loading of the involved biologic structures.

Purpose: To assess clinical performance of bar-retained implant overdentures (IOs) with distally placed ERA attachments on four implants, and patient satisfaction after a followup period of 5 years in a convenience selection of 15 patients. Materials and Methods: Bar-retained IOs with distally placed ERA attachments were placed and clinically monitored. Encountered complications during a 5-year follow-up period were recorded; and a modified OHIP-14 questionnaire was used to assess patient satisfaction. Results: Implant and restoration survival rates of 97.5% and 100%, respectively, were recorded. The most common maintenance requirement was the replacement of ERA retentive elements. A high degree of patient satisfaction was reported. Conclusions: The proposed IO design is a reliable clinical treatment protocol associated with a high degree of patient satisfaction and minor prosthetic complications.

Purpose: The aim of this study was to examine the fit accuracy of e.max crowns by investigating marginal and internal gaps. Materials and Methods: In experiment 1, 60 e.max computer aided design/computer-assisted manufacture (CAD/CAM) crowns were manufactured. The crowns were fabricated using optical scanning of artificial teeth (Op group) or scanning of a plaster model following a silicone impression (M group). Cement space settings of 90, 120, and 150 μm were applied. Marginal and internal crown gaps were compared among six conditions (Op90, Op120, Op150, M90, M120, M150). In experiment 2, e.max CAD crowns from the Op group (CADop group) and the M group (CADm group) were compared with e.max Press crowns (Press group) by measuring marginal and internal gaps of the crowns using Scheffe multiple comparison test. The level of significance was set at .05. Results: In experiment 1, the marginal gap of the Op90 group was significantly higher than that of the Op120 and Op150 groups. The marginal gap of the M90 group was significantly higher than those of the M120 and M150 groups, and the internal gap of the M90 group was significantly lower than that of the M150 group. Although there was no statistically significant difference in marginal gap among the three groups, the internal gap of the CADm group was significantly higher than the Press group. Conclusion: Although the variation in cement space settings and fabrication techniques affected accuracy, e.max CAD crowns fabricated using optical scanning of melamine teeth achieved a clinically acceptable fit.

A retrospective evaluation of 24 subjects treated with one-piece (1P) (n = 34) and two-piece (2P) (n = 38) implants placed in contralateral mandibular premolar locations was conducted. Cumulative implant survival was 100% following a 5-year (range = 59.9-72.3 months; mean = 63.1 months) postrestoration monitoring period. Bone loss (P = .1952) and prosthetic complications (P = .3667) did not significantly differ between the two groups. Clinical efficacy was equivalent for both implant designs.

The most common complication of implant ball attachments is loss of retention via structural wear. Hence, parallel placement of implants was identified as a prerequisite for longterm success. In this case, although severe angulation was formed between implants due to severe alveolar bone resorption, parallel ball attachments on the implants could be fabricated using computer-aided design/computer-assisted manufacture. This procedure can be a solution when implants are placed with angulation and offers additional advantages such as long-term stability.

Having multiple congenitally missing anterior teeth heavily influences the patient's countenance and pronunciation. There are few reports on the esthetic restoration of such situations with oral implants. This clinical case history report presents a multidisciplinary approach to treat a young woman with multiple congenitally missing anterior teeth using implant-supported prostheses. The treatment steps and clinical implications are discussed.