The International Journal of Prosthodontics, 04/2011

Purpose: The aim of this study was to compare survival rates and radiographic outcomes of immediate and delayed implant loading in edentulous maxillae. Materials and Methods: Forty-nine patients in need of maxillary full-arch treatment were randomized into two groups: test group (n = 34) treated following the Columbus Bridge Protocol with 4 to 6 implants loaded within 24 hours and a control group (n = 15) treated following the ad modum Brånemark protocol with 6 to 9 implants loaded a mean 8.75 months after surgery. Two hundred sixty implants (test: n = 163, control: n = 97) were placed, and subjects were treated with screw-retained full-arch prostheses. Bone levels were measured at baseline and at 1, 2, and 3 years and analyzed using repeated-measures analysis of variance. Results: All patients appeared at all scheduled recall visits. No differences in cumulative survival rates were found between groups at 36 months. Ten implants (6.1%) failed in the test group; four (4.1%) failed in the control group. At 36 months, no prosthetic failures were detected. Significantly less bone loss was found in the test group at all time intervals (P .001). The average bone level from the implant-abutment connection was 1.3 mm in the test group and 1.9 mm in the control group at 12 months, 1.5 mm and 2.2 mm at 24 months, and 1.6 mm and 2.3 mm at 36 months, respectively. Conclusion: In the edentulous maxilla, the Columbus Bridge Protocol involving immediate loading of implants placed in both healed and fresh extraction sites exhibited equivalent implant survival and less marginal bone loss at 3 years compared to the conventional two-stage delayed loading protocol.

The aim of this research was to analyze satisfaction with prosthodontic rehabilitation of intellectually disabled (ID) patients provided by their parents/caregivers. A total of 12 ID patients received fixed dentures (FDs) and 10 patients received removable dentures (RDs). Parents/caregivers answered a questionnaire related to prosthodontic rehabilitation (1 = unsatisfactory, 5 = excellent). Parents/caregivers were mostly satisfied with their childrens' oral rehabilitation (results were skewed toward the highest scores). There was a significant improvement in masticatory function and a reduction of avoiding certain foods after both FD and RD therapy. RD therapy significantly improved ID patients' social lives. However, FD therapy increased problems with oral hygiene maintenance. Prosthodontic rehabilitation improves oral function of ID patients.

Purpose: This retrospective study sought to examine posterior mandibular ridge resorption under implant-supported and implant-retained distal extension partial overdentures in men at the end of a 5-year observation period. Materials and Methods: Class I mandibular partial edentulism was managed in 34 patients with removable partial overdentures that were adjunctively supported (n = 18) or retained (n = 16) via resilient attachments placed bilaterally on single implants (n = 68) in the first molar areas. Posterior Area Indices (PAI) were calculated for each patient by digitizing the traced rotational tomograms taken immediately before and after 5 years of treatment. Proportional rather than actual measurements were used in an effort to minimize errors related to magnification and distortion. Results: Residual ridge resorption associated with the implant-supported partial overdentures was recorded as PAI =0.012 ± 0.022; it was PAI = 0.073 ± 0.044 for the implant-retained group. Estimated average reductions in ridge heights were 0.15 and 1.03 mm for implant-supported and implant-retained partial overdentures, respectively. Multiple linear regression models demonstrated that prosthesis type, initial mandibular ridge height, and relining frequency were significantly correlated with PAI. Conclusion: Implant-supported partial overdentures appear to be associated with reduced posterior mandibular alveolar ridge resorption when compared to implant-retained ones.

Purpose: The aim of this clinical retrospective study was to evaluate the survival and success rates of metal-ceramic fixed partial dentures (FPDs) made by dental students over an 18-year interval. Biologic and technical complications as well as patient satisfaction were recorded. Materials and Methods: Fifty-seven patients with 82 FPDs from an original group of 104 patients with 128 FPDs attended an approximate clinical 18-year follow-up examination. The mean follow-up period was 17.7 years (range: 17.1 to 21.3 years). Results: Nine FPDs were lost because of extraction of an abutment tooth, and 1 FPD was removed for esthetic reasons. Technical problems recorded included loss of cementation, fractures in the metal framework, and need for placement of a dowel in an abutment tooth. The most common clinical findings were gingival bleeding on probing and appearance of supragingival crown margins. The survival rate of the FPDs was 78%, and the established success rate was 71%. Conclusion: This 18-year follow-up of metal-ceramic FPDs in just over half of the originally treated patient group was associated with good patient satisfaction and few biologic and technical complications.

Purpose: The aim of this case-control study was to investigate the role female hormone fluctuation plays in maximum occlusal force and masticatory performance in female subjects presenting disc displacement with reduction (DDR) and matched controls. Materials and Methods: Sixty-five subjects were initially recruited; however, 4 of them were excluded during the study. The final sample included 14 subjects with DDR taking oral contraceptives, 16 control subjects without DDR taking oral contraceptives, 14 normally cycling subjects with DDR, and 17 normally cycling subjects without DDR. DDR was diagnosed by means of the Research Diagnostic Criteria for Temporomandibular Disorders axis I, and subjects without pain were selected. Maximum occlusal force was measured bilaterally in the molar region using a force transducer, and masticatory performance was analyzed using the artificial material comminution and sieving method. Variables were evaluated in four phases of three menstrual cycles, identified by ovulation testing. Data were submitted to the Mauchly sphericity test and PROC MIXED procedure of the SAS statistical program for repeated measures. Multiple comparisons were made using the Tukey-Kramer test (P = .05). Results: Comparisons among menstrual cycle phases showed no differences in occlusal force (P = .44) or masticatory performance (P = .09) for all volunteers. Subjects without DDR showed greater occlusal force (P = .01). No difference in occlusal force was found between subjects regardless of whether they took contraceptives (P = .15). Similarly, masticatory performance values did not differ among subjects with or without DDR (P = .09) or among those taking or not taking contraceptives (P = .29). Conclusion: Hormonal fluctuation did not influence mastication.

Limited clinical research identifies prosthodontic maintenance requirements of mandibular overdentures using the Locator attachment system. Sixty-five edentulous participants received complete maxillary dentures opposing mandibular two-implant overdentures with either Locator nylon (n = 21), Southern plastic (n = 24), or Straumann gold (n = 20) matrices. Prosthodontic maintenance was recorded prospectively for 3 years using defined categories. Over the 3-year period, a mean 3.52 ± 4.8, 2.08 ± 1.9, and 5.5 ± 4.2 maintenance events occurred for Locator, Southern, and Straumann participants, respectively. Prosthodontic success rates of 90% in the Locator nylon group, 88% in the Southern plastic group, and 75% in the Straumann gold group were achieved.

Purpose: The aim of this study was to develop and verify the reliability and validity of a questionnaire to assess patient satisfaction with fixed dental prostheses (FDPs). Materials and Methods: A questionnaire was developed, pilot-tested, and modified. It assessed esthetics, masticatory function, phonetics, cleansibility, and cost satisfaction using a visual analog scale and whether patients would elect to undergo the same treatment again (yes/no). It was sent to patients with a known evidence-based outcome (survival) who received FDPs from 1984 to 2005 (n = 986) in one private prosthodontic practice. Reliability and validity were analyzed using the Student t, Mann-Whitney U, Kruskal Wallis, Cronbach alpha, Spearman-Brown, Correlation matrix, Bartlett sphericity, Kaiser-Meyer-Olkin (KMO), and factor analysis tests. Significance was set at P = .05. Results: Five hundred patients responded (50.7%). A Cronbach alpha value of 0.8 and split-sample Spearman-Brown value of 0.7 indicated good reliability. Step-wise removal of items did not improve internal consistency. Discriminant construct validity assessment showed no item redundancy. Satisfaction of patients who had experienced prosthesis failure (n = 52) was significantly less than their counterparts (73% ± 3% vs 83% ± 0.6%, P = .004), ascertaining convergent construct validity. Factor analysis (Bartlett sphericity, P .001; KMO = 0.84) identified two components (Eigenvalues >= 1.0) that explained 93.18% (varimax rotation) of variations. Component 1 included satisfaction with function (esthetics, mastication, phonetics, and cleansibility); component 2 included satisfaction with costs and whether patients would undergo the same treatment again. Conclusions: The Patient Satisfaction Questionnaire developed proved reliable and valid for assessing patient-evaluated outcomes of FDPs. Use of this questionnaire in further research is justified.

A stereophotogrammetry technique is described that can be used to map the face following surgery for head and neck cancer. It enables the effects of obturators on facial form to be assessed and may have a wide variety of applications.

Purpose: Implant treatment has been performed for more than 45 years, but there is still limited knowledge on how treatment outcomes are changing over time. The aim of this study was to report and compare the treatment outcomes of two patient cohorts from the same clinic, rehabilitated with fixed implant prostheses in the edentulous maxilla between 1986 and 1987 (early) and 2001 to 2004 (late). Materials and Methods: The early group included 76 edentulous patients who were consecutively provided with 450 turned Brånemark System implants; the late group included 109 edentulous patients provided with 360 turned and 310 TiUnite Brånemark System implants. Both groups were followed and evaluated clinically and radiographically for 5 years according to similar protocols. Results: Altogether, 37 patients (20%) were lost to follow-up over 5 years; more patients were noncompliant in the late group (P .05). The 5-year overall implant cumulative survival rates were 93.4% and 97.3% for the early and late groups, respectively. In the early group, significantly more turned implants failed before prosthesis insertion compared to the outcome of TiUnite implants in the late group (P .05). Mean bone loss was comparable for the early and late groups during the 5 years of follow-up (0.5 ± 0.46 and 0.7 ± 0.76 mm, respectively), but more patients presented at least 1 implant with more than 2 mm of bone loss during the follow-up period in the late group (P .05). Mucosal hyperplasia and inflammation showed a trend of higher frequency at implants in the early group of patients (P > .05). Conclusion: Implant treatment was more predictable before loading in the late group of patients, related to the change in the implant surface (P .05). On the other hand, it was observed that the prevalence of patients with more bone loss at at least 1 implant (> 2 mm) was higher in the late group (P .05). This could possibly be attributed to a more bioactive implant surface and shorter healing period before implant surgery in the late group.

Purpose: Implant treatment using osseointegrated implants has been performed for more than 40 years, but limited knowledge is available on how treatment outcomes have changed over time. The aim of this study was to report and compare the prosthetic treatment outcomes from two patient cohorts provided with fixed implant prostheses in the edentulous maxilla between 1986 and 1987 (early) and 2001 to 2004 (late) at the same clinic. Materials and Methods: The two groups of patients comprised 76 and 109 edentulous patients consecutively provided with 450 and 670 Brånemark System implants and fixed screw-retained prostheses, respectively. Both groups were followed for 5 years with regard to prosthetic treatment, clinical maintenance, and complications. Results: Altogether, 37 patients (20%) were lost to follow-up during the 5 years, and more patients were noncompliant in the late group (P .05). Prosthetic treatment was performed using significantly less chair time in the late group (P .05), and 22 and 68 patients were followed for 5 years without any reported complications in the early and late groups, respectively (P .05). The 5-year prosthesis cumulative survival rate was 97.1% in the early group and 100.0% in the late group. Patients in the late group presented fewer problems with diction and veneer fractures, and fewer patients had their prostheses temporarily removed for adjustments (P .05). Conclusion: Prosthetic treatment and maintenance of implant-supported fixed prostheses improved significantly between the groups.

Purpose: This controlled clinical trial aimed to compare the 3-year outcomes of glass fiber posts and composite cores with gold alloy-based posts and cores for the restoration of endodontically treated teeth. Materials and Methods: One hundred forty-four patients in need of 205 restorations on endodontically treated teeth were selected and followed for 7 to 37 months (mean: 21 ± 9 months). The teeth were primarily stratified based on the remaining tissue available to restore the tooth core with or without a post. Then, randomization allocated the teeth to either test group 1 (prefabricated glass fiber posts), test group 2 (custom-made glass fiber posts), or test group 3 (composite cores without posts). The control group consisted of gold alloy-based posts and cores. All posts/cores were covered with all-ceramic single crowns. Failures were either absolute, such as root fractures or irreparable fractures of the post/core, or relative, such as loss of post retention or reparable fractures of the core. Success and survival probability lifetime curves, corrected for clustering, were drawn for the entire data set. Results: The recall rate at 3 years was 97.1%. Absolute failures consisted of two root fractures and one endodontic failure, while relative failures included three instances of retention loss of the post/core and one post fracture. Because of the low number of events, no statistical tests were performed. The success and survival probabilities over all groups together at 3 years amounted to 91.7% and 97.2%, respectively. Conclusions: After being followed for up to 3 years, both cast gold and composite post and core systems performed well clinically. Longer follow-up times are needed to detect possible significant differences.

The aim of the present in vivo study was to examine the effect of polytetrafluoroethylene (PTFE) surfaces on biofilm formation on dental implant abutments in comparison to titanium surfaces. Fifteen modified abutments with incorporated PTFE plates were inserted in 10 patients for 14 days. Scanning electron microscopy techniques were used to examine biofilm formation on different surfaces and to determine the percentage of surface coverage. Significantly less biofilm was detected on PTFE surfaces than on titanium surfaces. The results of this study reveal that PTFE surfaces reduce biofilm formation to a minimum on dental implant abutments.

This study evaluated the combined effects of thermocycling and compressive load-cycling on microleakage of computer-aided design/computer-assisted manufacture molar crowns. Sixteen ceramic (Vita Mark-II) and 16 composite resin (Paradigm MZ-100) crowns were milled using the CEREC 3D system. Eight crowns of each group were cemented to prepared molars using Panavia F 2.0, and 8 were cemented using RelyX Unicem Clicker. Specimens were thermocycled for 500 cycles and subjected to load-cycling for 1,000,000 cycles (60 to 600 N). Specimens were then tested for microleakage. Data were analyzed statistically using the Tukey post hoc test. All composite resin crowns survived load and thermal fatigue, while 6 ceramic crowns developed cracks. There were no statistically significant differences among groups regarding microleakage scores. Paradigm MZ-100 crowns were more crack-resistant to combined load and thermal fatigue than those composed to Vita Mark-II. However, microleakage scores of both types of crowns were similar.

The aim of this study was to evaluate the marginal adaptation of Turkom-Cera all-ceramic crowns compared to In-Ceram and Procera AllCeram systems. The influence of finish line design (chamfer or shoulder) on the marginal adaptation of Turkom-Cera all-ceramic crowns was also investigated. Thirty human premolars were prepared with chamfer margins and assigned to either the Turkom-Cera, In-Ceram, or Procera system group. In addition, 10 premolars were prepared with rounded shoulder finish lines and assigned to an additional Turkom-Cera group. Ceramic copings (0.6-mm thick) were fabricated for each group following the manufacturers' instructions. The copings were seated on abutments using a special holding device that facilitated uniform loading, and marginal adaptation was assessed using a stereomicroscope. Data were analyzed using analysis of variance, the Tukey HSD post hoc test, and an independent samples t test. There was a statistically significant difference regarding marginal adaptation among the three all-ceramic systems (P .05). There were no significant differences in the mean marginal discrepancies of Turkom-Cera crowns among chamfer and shoulder finish line groups (P > .05). Within the limitations of this study, the marginal discrepancies were all within the clinically acceptable standard.