The International Journal of Prosthodontics, 04/2006

Purpose: This study compared the speed and strength of osseointegration and osteoconductivity between an oxidized experimental magnesium (Mg) implant, an oxidized commercially available TiUnite implant, and a dual acid-etched surface Osseotite implant. The aim was to investigate which surface properties enhance bone response to implants, and thereby to test a biochemical bonding theory. Materials and Methods: A total of 60 screw implants (20 of each design) were inserted through 1 cortex into the tibiae of 10 rabbits. Surface chemistry, oxide thickness, morphology, crystal structure, and surface roughness were evaluated. After healing times of 3 and 6 weeks, all bone implants were unscrewed with removal torque (RTQ) devices, and the bone specimens were subjected to histomorphometry. Results: RTQ values for Mg, TiUnite, and Osseotite implants were 27.1, 21.3, and 15.4 Ncm, with new bone formation values of 29%, 18%, and 15%, respectively, at 3 weeks. At 6 weeks the RTQ values were 37.5, 36.4, and 21.5 Ncm, with new bone formation values of 39%, 31%, and 26%, respectively. Discussion: Mg implants demonstrated significantly greater RTQ values (P = .008 and P = .0001) and more new bone formation (P = .031 and P = .030) than Osseotite at 3 and 6 weeks, respectively. Mg implants also showed higher RTQ values at 3 weeks and new bone formation at 6 weeks than TiUnite, but neither were significant (P > .05). TiUnite showed significantly higher RTQ values than Osseotite at 6 weeks (P = .001), but was not significant at 3 weeks (P >.05). Osseointegration rate (ΔRTQ/Δweeks) was significantly faster for Mg (P = .011) and TiUnite (P = .001) implants between 3 and 6 weeks of healing time, but was not significant for Osseotite. Conclusions: The results indicate that surface chemistry facilitated more rapid and stronger osseointegration of the Mg implants despite their minimal roughness compared to the moderately roughened TiUnite. This suggests potential advantages of Mg implants for reducing high implant failure rates in the early postimplantation stage and in compromised bone, making it possible to shorten bone healing time from surgery to functional loading, and enhancing the possibility of immediate/early loading.

Purpose: This study examined the retentive forces of intracoronal precision attachments after wear cycling. Materials and Methods: Three material combinations of an intracoronal cylindric T-attachment were tested. A total of 10,000 separating and joining movements were performed, and retentive forces were measured. Results: Components made of gold alloy performed significantly better (P = .002) than other materials. The average proportional loss of retention was 90% for titanium and 47% for gold alloy components. Conclusion: Cyclic loading of metal precision attachment components results in loss of retention, which can be fully compensated by reactivating internal screws in the patrices. Machined, high-noble gold alloys show less wear than other materials.

Purpose: The aim of this study was to investigate the ability of clinical and magnetic resonance imaging (MRI) diagnoses to predict pain in the temporomandibular joint (TMJ). Materials and Methods: One hundred forty-nine patients were examined by 2 calibrated examiners in strict accordance with the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). All patients who presented with a defined clinical RDC/TMD diagnosis were included and underwent bilateral coronal and sagittal MRI of the TMJ. Two raters blinded to the clinical diagnosis interpreted the MRI scans for TMJ pathology. The results were tested against the clinical diagnosis according to the RDC/TMD, including pain-related disability and psychosocial status, for associations to TMJ arthralgia using logistic regression analysis (GENMOD procedure, P .05). Results: MRI-depicted anatomic changes, such as joint effusions, disc displacement, and osteoarthrosis, were not significantly correlated with the presence of pain in the TMJ. However, a significant relationship between pain on palpation of the masseter muscle origin (P = .0050) and psychosocial factors (P = .0452) and pain in the TMJ was demonstrated. Conclusions: Pain in the TMJ caused by the anatomic proximity of the muscle masseter origin and the lateral TMJ pole and the possible existence of trigger points in the musculature may lead to a false-positive or a false-negative diagnosis of arthralgia. Additionally, clinicians must consider the psychosocial aspects of pain in ideal treatment planning.

Purpose: To review the influence of prosthodontic and dental implant treatment on patient satisfaction and oral health-related quality of life (OHQOL) based on a systematic search of the literature. Materials and Methods: A systematic literature search was carried out for articles published between 1960 and February 2003. Details of the search process and results were reported in Part 1 of the study (Int J Prosthodont 2004;17:83-93). The included studies were categorized and evaluated according to their level of evidence, following the guidelines of the Agency for Health Care Policy and Research. The characteristics and content of the studies were analyzed and tabulated. Results: Among the 114 included studies, there were 76 publications reaching evidence level III. The results showed that the effects of compromised oral health are not limited to traditional clinical aspects, but can considerably affect patients in various activities of daily life. Twenty-four of the 38 investigations with evidence levels I and II dealt with implant stabilization of complete mandibular prostheses, comparing implant prostheses to conventional complete dentures. Fully edentulous patients experience negative impacts on OHQOL from their condition. They benefit significantly from the use of dental implants to support mandibular prostheses. However, support by more than 2 implants does not appear to further significantly increase patient satisfaction and OHQOL. Conclusions: To date, research in the field of patient-based outcomes has concentrated on dental implant treatment for the edentulous patient. Other prosthetic treatments such as single crowns, fixed and removable partial dentures, or further treatment concepts (eg, the shortened dental arch concept) are not well represented. The use of patient-centered outcome measures can help to find an individual, patient-oriented prosthetic solution.

Purpose: This study aimed to assess the efficacy and short-term effectiveness of the morphology and function of direct and indirect cusp-replacing resin composite restorations. Materials and Methods: In 94 patients, 106 cusp-replacing restorations for maxillary premolars were fabricated to restore Class II caries lesions with 1 cusp missing. Fifty-four direct (Clearfil AP-X) and 52 indirect (Estenia) resin composite restorations were placed following a strict protocol. The treatment technique and operator were assigned randomly. Treatment time was recorded for all restorations. One-month postoperative evaluation included assessment of postoperative sensitivity and presence of occlusal and proximal contacts. Results: Treatment time for the indirect technique (68 ± 17 min) was longer than for the direct technique (45 ± 13 min). Regression analysis revealed that the restorative method, operator, and location of the preparation outline had a statistically significant effect on the total treatment time. Occlusal contacts were observed in 94% of the direct restorations and in 98% of the indirect restorations (chi-square, P > .05). Mesial proximal contacts were present in 98% of the direct and in 97% of the indirect restorations (chi-square, P > .05). Distal contacts were present in 100% of the restorations for both techniques. Postoperative sensitivity within 1 week posttreatment was reported for 11% of the direct restorations and for 13% of the indirect restorations, but decreased to 4% and 6%, respectively, after 1 month (chi-square, P > .05). Conclusion: The results of this study suggest that in the short term, both direct and indirect adhesive techniques are adequate to restore the morphology and function of premolars presenting with Class II caries lesions and a missing cusp.

Purpose: VITA In-Ceram Classic is a system designed to fabricate all-ceramic crowns and fixed partial dentures (FPDs) with a glass-infiltrated aluminum oxide core material. This systematic literature review gives an overview of the clinical performance of the VITA In-Ceram Classic Alumina, Spinell, and Zirconia restorations. Materials and Methods: Based on a systematic literature review, an evidence-based selection and assessment of clinical studies of VITA In-Ceram Classic ceramics was carried out. Results: A total of 299 publications were found, 21 of which met the inclusion criteria. Only a few meaningful studies of In-Ceram Alumina FPDs and In-Ceram Zirconia crowns and FPDs were found. The 5-year survival rate of In-Ceram Alumina crowns and In-Ceram Spinell crowns ranged from 91.7% to 100% and is similar to the survival rate of conventional metal-ceramic crowns. The 5-year survival rate of single-retainer In-Ceram Alumina resin-bonded FPDs (RBFPDs) was 92.3%, which is higher than that of 2-retainer RBFPDs. Conclusion: In-Ceram Classic Alumina can be recommended for anterior and posterior crowns as well as for anterior single-retainer RBFPDs. Further studies should be initiated to evaluate in detail the clinical performance of In-Ceram Classic Alumina FPDs. In-Ceram Classic Spinell can be recommended for anterior crowns, especially if highly esthetic results are requested. For In-Ceram Classic Zirconia crowns or FPDs no statement can be made presently because of insufficient data.

Purpose: The aim of this study was to determine the correlation between personality type and denture satisfaction of totally and partially edentulous patients. Materials and Methods: Two hundred thirty-nine patients (107 women and 132 men) aged 31 to 78 years (mean, 51.87) using removable dentures (165 maxillary and mandibular partial, 51 maxillary and mandibular complete, and 23 maxillary complete and mandibular partial) were asked to fill out a questionnaire on their satisfaction with their dentures with regard to esthetics, speaking ability, and masticatory function. Personality types were evaluated using both the responses to this questionnaire and the Type A Behavior Pattern Test. Chi-square test and logistic regression analysis were used to compare the denture satisfaction scores of the groups (Type A, Type B, and Type AB). The level of statistical significance was set at P = .05. Results: Denture satisfaction of the patients with regard to esthetics, speaking ability, and masticatory function was affected by personality type. Statistically significant differences were found between Type A and types B and AB, as well as between types B and AB. Conclusion: The personality type of the patients had an effect on their satisfaction with dentures. The lowest denture satisfaction values were observed in the Type A patients.

This study aimed to compare the retentive forces of cast cobalt-chromium (Co-Cr) and commercially pure titanium (cpTi) clasps. A clasp assembly comprising a pair of symmetrical clasps was made to fit the opposite halves of a hardened stainless-steel sphere. This twin clasp was designed to counterbalance the tipping forces when the clasp assembly was drawn from the sphere. A total of 120 clasp assemblies were fabricated in cast Co-Cr and cpTi and placed at undercut depths of 0.25 mm, 0.50 mm, and 0.75 mm (n = 20 for each). For Co-Cr clasps, the retentive forces at these undercuts depths were 2.34 ± 0.23 N, 4.65 ± 0.35 N, and 7.56 ± 0.50 N, respectively. The corresponding retentive forces for cpTi clasps were 1.24 ± 0.13 N, 2.34 ± 0.23 N, and 3.70 ± 0.27 N. The retentive force of cpTi clasps was approximately half that of Co-Cr clasps for the same undercut depth.

Purpose: The aim of this in vitro study was to evaluate the marginal adaptation and retention of inlay fixed partial dentures (IFPDs) made with 1 fiber-reinforced composite and 2 different ceramic materials using quantitative scanning electron microscope analysis after thermal cycling and mechanical loading, which simulated approximately 5 years of oral service. Materials and Methods: Eighteen IFPDs made with fiber-reinforced composite (SR Adoro/Vectris), zirconium oxide-TZP (Cercon), and magnesia partially stabilized zirconia (DC-Leolux) covered with silica-based ceramics were tested in this study. The specimens were mechanically loaded in the vestibular cusp of the pontic element in a computer-controlled masticator with 1,200,000 half-sinusoid mechanical cycles of maximum 49 N each at a frequency of 1.7 Hz. A total of 3,000 thermocycles at 5°C and 55°C, 2 minutes each, were performed simultaneously. The marginal adaptation was analyzed at the interface of the luting composite and the abutment inlay/onlay (CI) and at the interface of the tooth and the luting composite (TC). Results: The percentages of continuous margin at the CI interface were 94.6 ± 3.1 and 88 ± 6.7 for Adoro/Vectris, 92.9 ± 5 and 85.7 ± 6.1 for Cercon, and 96.2 ± 2.1 and 82.2 ± 9.8 for DC-Leolux, respectively, before and after loading. The percentages of continuous margin at the TC interface were 86.7 ± 6.7 and 62.5 ± 16.4 for Adoro/Vectris, 93.3 ± 3.4 and 83.2 ± 5.9 for Cercon, and 96.1 ± 2.4 and 75.3 ± 7 for DC-Leolux. Statistically significant differences were found after loading between the fiber-reinforced composite and the 2 ceramic systems at the TC interface. Conclusion: Within the limitations of this experimental study with regard to the sample size and contacting vectors, the results showed that flexibility of the framework may play an important role in the marginal adaptation of the IFPDs. More rigid materials may transfer less stress to the margins, thus promoting a more stable adhesion to the dental tissues.

Purpose: Prosthetic rehabilitation of speech disorders related to palatopharyngeal dysfunction is accomplished through separation of the oral and nasal cavities. The ability to achieve this separation is challenged when the disorder or defect involves the soft palate. Prosthetic rehabilitation of soft palate disorders and defects has traditionally relied on functional contouring of a prosthesis using functionally adapted impression materials. However, there are limitations to this process, particularly in its inability to visualize function as it relates to the prosthesis in a 3-dimensional space. The aim of this study was to address this limitation by describing outcomes related to the use of nasopharyngoscopy (NPS) for visualization of the velopharyngeal port during assessment and treatment of palatopharyngeal dysfunction. Materials and Methods: A retrospective analysis of speech data was conducted for 5 patients who were assessed before treatment, after prosthetic intervention using conventional functional impression techniques, and after prosthetic intervention using NPS. Nasalance and velopharyngeal orifice area outcome measurements were collected for each patient at clinically predetermined intervals. Perceptual assessment of speech samples was performed as well. Results: Improvements in speech function were observed for all patients after treatment with a prosthesis designed via a conventional functional impression technique; however, no patient showed normal values for nasalance or velopharyngeal orifice area. With the use of NPS to adjust the wax impression-derived prosthesis, both nasalance and velopharyngeal orifice area measurements for all patients were within normal limits. Similarly, perceptual judgment of speech found that normal resonance balance was obtained after use of NPS. Conclusion: The addition of NPS into prosthetic treatment for palatopharyngeal disorders shows promise for improved speech results.

In this study, 19 patients were treated with 36 Brånemark System MK III TiUnite implants in the maxilla. Definitive implant-supported single crowns were delivered to patients 6 weeks after implant placement. Clinical and radiographic parameters were recorded at baseline, and at 1, 2, and 3 years. Both implant and prosthesis success rates were 94% after 3 years. The average marginal bone loss was 0.97 mm after 3 years. The results of this study indicate that 6-week early loading of TiUnite surface implants in the maxilla was reliable and predictable for this patient population and may offer an alternative to the standard loading protocol.

Purpose: This study aimed (1) to test the hypothesis that no significant relationship exists between the magnitude of occlusal clenching force and wear rates of enamel opposing a new core ceramic (e.max Press, Ivoclar Vivadent) used in posterior fixed partial dentures (FPDs); and (2) to test the hypothesis that mean annual enamel wear by an experimental core ceramic is comparable to the mean annual enamel wear by enamel of 38 µm. Materials and Methods: Baseline data were obtained for patients in addition to preliminary impressions of maxillary and mandibular teeth. Thirty ceramic FPDs were processed from a new core ceramic (e.max Press) that was hot pressed and glazed. Patients were recalled 1 year after cementation and evaluated using clinical criteria that included wear assessment of opposing teeth. Impressions were made of the opposing teeth with polyvinylsiloxane impression material and photographs were taken of intraoral occlusal contacts marked with articulating ribbon. Baseline casts and casts made at each recall exam of opposing dentitions were scanned using a 3-dimensional laser scanner (Laserscan 3D, Willytec) and evaluated for wear. A total of 21 occlusal surfaces were analyzed for the presence of wear. Results: Statistical analysis using a linear and quadratic model revealed no significant relationship between occlusal forces and wear rate assuming either a linear model (R2 = 0.018) or a quadratic model (R2 = 0.023). The maximum annual wear of enamel by the glazed core ceramic (e.max Press) was 88.3 µm, which is significantly greater than the annual enamel-by-enamel wear of 38 µm (P .0001). Conclusion: Further analysis with a larger sample size is needed to determine the relationship between occlusal clenching force and wear rate and the influence of other factors that cause increased wear of enamel by opposing ceramic restorations.

Purpose: The aim of this study was to evaluate the clinical performance of metal-ceramic crowns placed in 10 private practices. Materials and Methods: In this prospective clinical trial, 95 patients were provided with 190 noble-metal metal-ceramic single crowns. Results: The 7-year survival rates of the crowns were 95.5% (target event: any removal), 99.5% (target event: removal because of defective veneer), and 92.4% (target event: metal-ceramic complication of any kind). No significant explanatory variables for metal-ceramic complications could be detected by bivariate and multivariate testing. The consequences resulting from metal-ceramic defects were of minor clinical significance in most cases. Conclusion: The findings support previous claims that metal-ceramic restorations perform very well clinically, including in practices outside academic environments.

This study compared the microtensile bond strength of a repair resin to an alumina-reinforced feldspathic ceramic (Vitadur-a, Vita) after 3 surface conditioning methods: Group 1, etching with 9.6% hydrofluoric acid for 1 minute plus rinsing and drying, followed by application of silane for 5 minutes; group 2, airborne particle abrasion with 110-mm aluminum oxide using a chairside air-abrasion device followed by silane application for 5 minutes; group 3, chairside tribochemical silica coating with 30-µm SiOx followed by silane application for 5 minutes (N = 30). Group 1 presented the highest mean bond strength (19.7 ± 3.8 MPa), which was significantly higher than those of groups 2 (10 ± 2.6 MPa) and 3 (10.4 ± 4 MPa) (P .01). Scanning electron microscope analysis of the failure modes demonstrated predominantly mixed types of failures, with adhesive and/or cohesive failures in all experimental groups.

Purpose: The purpose of this study was to evaluate the prevalence, distribution, and associated factors of tooth wear among psychiatric patients. Materials and Methods: Tooth wear was evaluated using the tooth wear index with scores ranging from 0 to 4. The presence of predisposing factors was recorded in 143 psychiatric patients attending the outpatient clinic at the Prince Rashed Hospital in northern Jordan. Results: The prevalence of a tooth wear score of 3 in at least one tooth was 90.9%. Patients in the age group 16 to 25 had the lowest prevalence (78.6%) of tooth wear. Increasing age was found to be a significant risk factor for the prevalence of tooth wear (P .005). The occlusal/incisal surfaces were the most affected by wear, with mandibular teeth being more affected than maxillary teeth, followed by the palatal surface of the maxillary anterior teeth and then the buccal/labial surface of the mandibular teeth. The factors found to be associated with tooth wear were age, retirement and unemployment, masseter muscle pain, depression, and anxiety. Conclusion: Patients' psychiatric condition and prescribed medication may be considered factors that influence tooth wear.