The International Journal of Prosthodontics, 03/2010

Purpose: Problems associated with a complete denture, such as lack of stability and retention, can be solved with the use of implant-retained or implant-supported overdentures. However, controversy exists as to the anchorage system used and indications for both the maxilla and mandible. The purpose of this review was to identify the prosthetic complications associated with the different attachment mechanisms used for implant-supported or implant-retained overdentures. Materials and Methods: A search of the MEDLINE and PubMed databases was conducted to find articles in English and German peer-reviewed journals published between 1980 and 2008. The search focused on randomized controlled clinical trials and prospective studies with follow-up periods of at least 5 years that contained clinical data regarding success, failure, and prosthetic complications. Results: The search yielded a limited number of randomized controlled clinical trials referring to implant-supported or implant-retained overdentures. Very few studies have prospectively compared prosthetic complications for a period longer than 5 years after delivery of the prosthesis. Conclusions: Implant-supported or implant-retained overdentures in the mandible provide predictable results with improved stability, retention, and patient satisfaction. Scientific evidence shows a lower rate of implant survival and a higher frequency of prosthetic complications for maxillary implant-retained or implant-supported overdentures. Although the literature presents considerable information on complications of implant prostheses, variations in study design preclude proper analysis of certain complications. Well-designed longitudinal studies are required to establish evidence-based treatment planning principles.

Purpose: A before-and-after experimental clinical study was carried out with the objective of evaluating the effect of a mandibular advancement device (MAD; 75% advancement), made of a thermoplastic material, on sleep bruxism (SB) and sleep scores. Materials and Methods: After a habituation period of 1 week, SB scores were taken at baseline and after use of the MAD for 30 days. Scores were compared using the newly developed BiteStrip, which registers the number of contractions of the unilateral masseter muscle after a 5-hour period, giving a severity score from 0 to 3 after the registrations. To assess sleep, the Sleep Assessment Questionnaire (SAQ), a screening tool with scores ranging from 0 to 68, was used before and after use of the MAD. Twenty-eight subjects (13 women, 15 men; mean age: 42.9 ± 12.0 years) with a clinical history of SB and no spontaneous temporomandibular disorder (TMD) pain were selected. The clinical diagnosis of either moderate or severe SB was further confirmed through use of the BiteStrip (scores 2 or 3) at baseline. A 30-day follow-up period was used for evaluation. Both methods were validated against polysomnography. In addition, common signs and symptoms of TMD based on the Research Diagnostic Criteria for Temporomandibular Disorders were also evaluated before and after use to assess the side effects of the MAD. Results: There was a statistically significant improvement in both SB and sleep scores based on the BiteStrip and the SAQ (Wilcoxon signed rank and Student paired t test, P .05). In the signs and symptoms of TMD, there was a significant reduction in temporomandibular joint sounds as well as in masseter and temporalis tenderness to palpation. None of the SB subjects experienced any breakage of the MAD. Conclusion: The MAD had a positive effect on SB and sleep scores, measured by the BiteStrip and the SAQ, respectively, and did not increase any traditional signs and symptoms of TMD in a 30-day evaluation period.

The purpose of this preliminary study was to evaluate the clinical performance of chairside-generated crowns over a preliminary time period of 24 months. Forty-one posterior crowns made of a machinable lithium disilicate ceramic for full-contour crowns were inserted in 34 patients using a chairside computer-aided design/computer-assisted manufacturing technique. The crowns were evaluated at baseline and after 6, 12, and 24 months according to modified United States Public Health Service criteria. After 2 years, all reexamined crowns (n = 39) were in situ; one abutment exhibited secondary caries and two abutments received root canal treatment. Within the limited observation period, the crowns revealed clinically satisfying results.

Tardive dyskinesia (TD) is an involuntary movement disorder of neurologic origin caused by the use of neuroleptic drugs known as dopamine receptor antagonists. The condition may adversely affect prosthodontic interventions and their possible merits. In this case history description, the rigor of scrupulous history-taking and clinical evaluation of patients with TD or neurologic disorders is emphasized. The successful prosthodontic management of a 74-year-old completely edentulous TD patient is presented, with the conclusion that a prosthodontic intervention may aid symptom reduction and contribute to improvement in a TD patient's quality of life.

Purpose: No clinical evidence has been provided to suggest that metal-free all-composite resin indirect restorations are a functional and esthetic alternative to all-ceramic restorations. The aim of this study was to evaluate the clinical performance of single-tooth computer-aided design/computer-assisted manufacturing (CAD/CAM)-generated all-composite resin and all-ceramic crowns after 3 years of function. Materials and Methods: In a prospective trial, 200 all-composite resin and all-ceramic crowns were rated over a 3-year period. Restorations were evaluated at 3 weeks and 1 and 3 years after insertion by the California Dental Association quality evaluation index, the patient's self-assessment, marginal fit, periodontal parameters, volume loss, and wear patterns of the veneering material. Statistical analysis was performed using t tests (a = .05). Results: Cumulative survival and success rates after 3 years were 87.9% and 55.6% for all-composite resin and 97.2% and 81.2% for all-ceramic crowns, respectively (P .05 for success rates). Restoration loosening occurred exclusively for all-composite resin crowns cemented on a cast post. All-ceramic restorations demonstrated satisfactory esthetic results. All-composite resin crowns resulted in significantly more mean total volume loss and mean vertical wear at occlusal contact areas after 6 months and 3 years of function. The clinical performance of the CAD/CAM-generated all-ceramic crowns used in this study was similar to that of other all-ceramic CAD/CAM systems. Conclusion: For up to 3 years of function, all-composite resin single-tooth restorations have inferior success rates compared to all-ceramic restorations. Due to the inferior esthetics and wear resistance of all-composite resin crowns, all-ceramic crowns remain the preferred treatment for CAD/CAM-generated metal-free single-tooth restorations.

Purpose: The aim of this investigation was to evaluate the clinical outcome of two different surgical protocols in the edentulous mandible: submerged and nonsubmerged. Further, the Paragon dental implant with a titanium plasma-sprayed surface was evaluated. Materials and Methods: Twenty-nine consecutively treated patients with 168 implants supporting fixed prostheses were included. All but 3 patients were provided 6 implants, placed via nonsubmerged healing on one side and submerged healing on the other. Data were collected from patient records and radiographs. Twenty-four patients participated in the 5-year clinical follow-up examination. Results: After 5 years, all patients still had their mandibular fixed prostheses in function. Cumulative survival rates were 100% for prostheses and 99.4% for implants. However, 3 implants fractured in 1 patient. One submerged implant was lost before loading but no further implants were lost during follow-up. The radiographic bone loss was small for all implants with a mean of 0.14 mm (standard deviation [SD]: 0.37) at 1 year and 0.42 mm (SD: 0.48) at 5 years for nonsubmerged implants and 0.17 mm (SD: 0.32) at 1 year and 0.51 mm (SD: 0.33) at 5 years for submerged implants. Nineteen implants (including the 3 that fractured) presented annual bone loss exceeding 0.2 mm after the first year, yielding a cumulative success rate of 86.2% after 5 years. Conclusion: Single-stage surgery was shown to have the same predictability as two-stage surgery in the anterior edentulous mandible. Paragon implants with a titanium plasma-sprayed surface showed a fracture rate of 2.2% and a success rate of 86.2% after 5 years.

This study assessed how biofilm composition is affected by both time and denture material in complete denture wearers. Biofilm was formed during two phases of 14 days on acrylic resin and denture liner specimens mounted on the buccal surface of the mandibular dentures of 21 patients. Specimens were removed randomly on days 2, 7, and 14. Higher counts of Candida glabrata, total streptococci, Actinomyces, total microorganisms, and percentage of Actinomyces were observed after 7 and 14 days (P .05). C glabrata was the only species to show progressively rising counts from day 2 to 14, while no difference was found in biofilm composition among the materials tested.

This study aimed to investigate the occurrence of subpontic tissue enlargement (STE) beneath a mandibular fixed partial denture. A 55-year-old Japanese woman received periodontal therapy and cross-arch fixed partial dentures were placed in the maxilla and mandible. After 18 years, STE developed in the left posterior region of the mandible. It was presumed that biomechanical loading in the mandible, along with other factors, might have caused the STE in this particular patient.

This study compared the shear bond strength and failure types of a polymethyl methacrylate (PMMA) denture base resin to commercially pure (CP) titanium, Ti-6Al-4V alloy, and cobalt-chromium alloy using a metal surface conditioner. The PMMA denture base resin (5 x 5 x 5 mm3) was cured onto disks, 10 mm in diameter and 2.5-mm thick. The shear bond strength of the PMMA resin with the surface conditioner was significantly higher than that without (P .05). There was no significant difference between the types of metal. The conditioned specimens showed mixed failures, whereas the nonconditioned specimens exhibited only adhesive failure at the metal-resin interface.

Purpose: Despite the interest and need to assess orofacial esthetics in prosthodontic patients, few self-reporting instruments are available to measure this construct, and none describe how prosthodontic patients perceive the appearance of their face, mouth, teeth, and dentures. The development of the Orofacial Esthetic Scale (OES) is reported in this article, in particular its conceptual framework, how questionnaire items were generated, and the scale's measurement model. Materials and Methods: After test conceptualization, the authors solicited esthetic concerns from 17 prosthodontic patients by asking them to evaluate their own photographs. A focus group of 8 dental professionals reduced the initial number of concerns/items and decided on an item response format. Pilot testing in 9 subjects generated the final instrument, the OES. Exploratory factor analysis was performed to investigate OES dimensionality and item analysis to investigate item difficulty and discrimination in 119 subjects. Results: Prosthodontic patients generated an initial 28 esthetic concerns. These items were reduced to 8 preliminary representative items that were subsequently confirmed during pilot testing. Analysis supported 8 items assessing appearance: face, profile, mouth, tooth alignment, tooth shape, tooth color, gums, and overall impression, measured on an 11-point numeric rating scale (0 = very dissatisfied, 10 = very satisfied). Exploratory factor analysis found only 1 factor and high positive loadings for all items (.73 to .94) on the first factor, supporting the unidimensionality of the OES. Conclusions: The OES, developed especially for prosthodontic patients, is a brief questionnaire that assesses orofacial esthetic impacts.

Purpose: This study evaluated the reliability and validity of the Orofacial Esthetic Scale (OES)-an instrument assessing self-reported orofacial esthetics in prosthodontic patients. Materials and Methods: The OES has seven items addressing direct esthetic impacts in the orofacial region, as well as an eighth global assessment item. The response format was a 0 to 10 numeric rating scale (very dissatisfied to very satisfied with appearance, respectively). OES summary scores ranged from 0 (worst score) to 70 (best score). Test-retest reliability (n = 27) and internal consistency (n = 119) were assessed. Content validation (asking patients about their satisfaction with the questionnaire content, n = 119) and discriminative validation (comparing OES scores between patients and healthy controls, n = 119) were performed. Convergent validity was assessed by correlating patients' own OES scores (n = 29) with ratings from a consensus expert group (n = 4) and with the Oral Health Impact Profile (OHIP) esthetic-item summary score (n = 119). Results: Test-retest reliability was excellent for the OES scores (intraclass correlation coefficient = .96). Internal consistency was satisfactory for esthetically impaired patients (n = 27, Cronbach alpha = .86). Patients rated their satisfaction with the questionnaire content as 7.8 ± 1.3 units on a 0 to 10 numeric rating scale (0 = very dissatisfied, 10 = very satisfied). OES scores discriminated esthetically impaired patients (31.4 units) from healthy controls (45.9 units, P .001). OES scores correlated well with other measures of the same construct (r = .43 for patients' own assessment with an assessment by experts using the OES, r = -.72 for a correlation with the OHIP's three esthetic-related items). Conclusions: The OES, developed especially for prosthodontic patients, exhibited good score reliability and validity.

Purpose: Extraoral maxillofacial prostheses have been fabricated with silicone elastomer for 50 years with few improvements. The objective of this controlled, randomized, prospective, double-blind, single-crossover, multicenter, phase III clinical trial was to determine the noninferiority of chlorinated polyethylene elastomer (CPE) to silicone elastomer for fabricating prostheses. Materials and Methods: Forty-two patients were randomly assigned to wear a custom-made prosthesis fabricated from both materials for 4 months and asked to rate their satisfaction (0 = not satisfied, 10 = completely satisfied). Many other measures of prosthesis performance were investigated (see online appendices). Results: Of the 28 patients who completed the study, 68% had used silicone prostheses previously. Overall, patients rated the silicone prosthesis higher than CPE (difference: 2.2, 95% confidence interval [CI]: 0.9 to 3.6, P = .017). Previous users had a stronger preference for silicone (difference: 3.3, 95% CI: 1.7 to 4.9, P = .001), while the 9 new users rated the two materials similarly (difference: 0.0, 95% CI: -2.1 to 2.1, P = 1.00). Conclusions: The noninferiority of CPE could not be established because of the early termination of the trial. Previous users of silicone prostheses preferred those made of silicone. However, new users expressed no preference between prostheses fabricated with the low-cost CPE or silicone. The authors have developed original clinical trial methodology for assessing extraoral maxillofacial prostheses.

Purpose: The aim of this research was to assess the dimensional accuracy of orbital prostheses based on reversed images generated by computer-aided design/ computer-assisted manufacturing (CAD/CAM) using computed tomography (CT) scans. Materials and Methods: CT scans of the faces of 15 adults, men and women older than 25 years of age not bearing any congenital or acquired craniofacial defects, were processed using CAD software to produce 30 reversed three-dimensional models of the orbital region. These models were then processed using the CAM system by means of selective laser sintering to generate surface prototypes of the volunteers' orbital regions. Two moulage impressions of the faces of each volunteer were taken to manufacture 15 pairs of casts. Orbital defects were created on the right or left side of each cast. The surface prototypes were adapted to the casts and then flasked to fabricate silicone prostheses. The establishment of anthropometric landmarks on the orbital region and facial midline allowed for the data collection of 31 linear measurements, used to assess the dimensional accuracy of the orbital prostheses and their location on the face. Results: The comparative analyses of the linear measurements taken from the orbital prostheses and the opposite sides that originated the surface prototypes demonstrated that the orbital prostheses presented similar vertical, transversal, and oblique dimensions, as well as similar depth. There was no transverse or oblique displacement of the prostheses. Conclusion: From a clinical perspective, the small differences observed after analyzing all 31 linear measurements did not indicate facial asymmetry. The dimensional accuracy of the orbital prostheses suggested that the CAD/CAM system assessed herein may be applicable for clinical purposes.