The International Journal of Prosthodontics, 02/2005

Purpose: The purposes of this study were to: (1) determine patient satisfaction with implant-supported mandibular overdentures using magnet, bar-clip, and ball-socket attachments; and (2) assess the relation between maximum bite force and patient satisfaction. Materials and Methods: In a cross-over clinical trial, 18 edentulous patients with mandibular denture complaints received two mandibular implants and new mandibular and maxillary dentures. The mandibular denture was initially without any kind of attachment system, but it was fitted with one of the attachment types after 3 months. The attachments were changed 3 months thereafter, in random order. A questionnaire on denture complaints was administered at baseline (with the old denture), after 3 months of function with the new denture without attachments, and after 3 months of function with each of the attachments (within-subject comparison). In addition, patients were asked to express their overall appreciation of their dentures on a VAS. Patients' preferences were determined at the end of the experiment. Maximum bite forces were obtained from a previous study with the same population. Five scales of denture complaints were constructed. Mean scale and VAS scores at the five evaluation points were compared among the groups. Pearson correlation was calculated between maximum bite force and scale and VAS scores. Results and Conclusion: Mandibular implant-supported overdenture treatment reduced various denture complaints. The VAS score better reflected patients' preferences than did scale score. Patients strongly preferred bar-clip (10/18 subjects) and ball-socket attachments (7/18 subjects) over magnet attachments (1/18 subjects). Patients' preferences could not be predicted on the basis of baseline observations. Maximum bite force was not correlated to scale or VAS score. Hence, patients with higher maximum bite forces were not necessarily more satisfied.

Purpose: Previous studies investigating associations between patient personality traits and complaints related to wearing dental prostheses have been inconclusive. From the perspective of cognitive behavioral theory, the current study investigated whether pain sensitivity, body consciousness, and somatization affected the oral health of patients wearing removable dentures. Materials and Methods: Eighty-eight patients were supplied with removable partial and complete dentures. The Oral Health Impact Profile (OHIP), with six subscales measuring oral health impairment and disability during daily living, the Pain Sensitivity Index, the Private Body Consciousness scale, and the Somatization Scale of the SCL-90-R, were used. Results: The variables pain sensitivity, body consciousness, and somatization correlated significantly with all six OHIP subscales in removable denture wearers. In multiple hierarchic regression analyses, patient personality accounted for 38.0% of functional limitation and 41.5% of physical pain. Conclusion: Pain sensitivity and bodily preoccupation might be important factors in explaining the subjective oral health effects of removable denture wearing.

Purpose: The aims of this study were to evaluate the in vitro shear bond strength of the dentin-titanium interface mediated by Fuji Plus, a resin-modified glass-ionomer cement, applied in combination with several self-etching bonding systems, and to compare the values obtained with those of SuperBond, chosen as a reference luting agent. Materials and Methods: The self-etching bonding systems used in combination with Fuji Plus were AdheSE, Xeno III, Clearfil SEBond, Unifil Bond, and an experimental self-etching bonding system comprising the sequential application of Xeno III and the bonding component of SE Bond. Two control groups were also tested: a negative control with Fuji Plus along with its conditioner (10% ferric chloride, 2% citric acid solution); and a positive control with the resin cement SuperBond. One hundred five human molars were used to prepare seven groups of fifteen samples each. The samples were tested in shear after 7-day storage at 100% relative humidity and 37°C. Results and Conclusion: Three of the tested combinations of self-etching bonding systems with Fuji Plus significantly improved in comparison with the negative control group, from 9% to 44%. The self-etching bonding systems obtained using Fuji Plus in combination with Clearfil SEBond, Unifil Bond, and the experimental system were not different from those obtained with SuperBond.

Purpose: The study's aim was to report long-term costs in edentulous patients treated with mandibular implant-supported prostheses. Materials and Methods: Ninety patients were divided into four groups based on the type of implant prosthesis (fixed or overdenture) and treatment year. Records were obtained from dental charts, and an economic analysis from the patient's perspective was conducted. Clinical time associated with various procedures was measured and applied to the four groups. Salary rates by age, occupation, and gender were used to value patients' time. Direct clinical and time costs over 10 years were converted to 2002 Canadian dollars using the Consumer Price Index and discounted at a 3% rate. A sensitivity analysis at an equal salary rate was carried out to test the robustness of the time costs. Results: Initial treatment and maintenance costs over the observation period were significantly higher for fixed compared to overdenture prostheses. A significant improvement in maintenance costs for the first patient group treated with fixed prostheses was observed over the follow-up period. Longer term (15 years) treatment costs for the initial two groups were significantly higher for the fixed group. The sensitivity analysis at an equal salary rate demonstrated the same trend: Time costs were significantly higher for the fixed groups. Conclusion: Long-term treatment costs indicated that the mandibular overdenture was a less expensive treatment compared to the fixed implant prosthesis.

Purpose: This study sought to investigate problems reported by patients before and after prosthodontic treatment. Materials and Methods: Patient-reported problems were studied using the item list contained in the German version of the Oral Health Impact Profile in a convenience sample of 107 prosthodontic patients before (T₀), 1 month after (T₁), and 6 to 12 months after treatment (T₂). "Frequently reported" problems were defined as impacts experienced fairly often or very often. The prevalence of frequently reported problems was compared among treatment groups and across appointments. Results: At baseline, the most prevalent frequently reported problems were "difficulty chewing" (31%), "take longer to complete a meal" (28%), "food catching" (26%), "uncomfortable to eat" (24%), and "unable to eat (because of dentures)" (23%). At T₂, the most prevalent frequently reported problems were "sore spots" (5%), "painful gums" (4%), "discomfort (because of dentures)" (3%), and "sore jaw" (2%). The number of reported problems decreased from 18.0 (T₀) to 7.5 (T₁), and further to 4.5 (T₂). The decrease was the fastest in fixed partial denture wearers and the slowest in removable partial denture wearers. Some problems emerged during or after prosthodontic treatment. The kind of pre- and posttreatment problems differed substantially. Conclusion: The number of problems decreased substantially after prosthodontic treatment. Fixed partial dentures more effectively influenced the problems reported before treatment than did removable partial or complete dentures.

Purpose: The purpose of this prospective study was to provide a preliminary report of implant treatment in patients with neurologic disabilities. Materials and Methods: Patients had been referred to the National Orofacial Resource Centre with different disabilities, specifically neurologic disorders causing various orofacial dysfunction problems, and were suitable for prosthodontic treatment with implants. Patients were treated with single implant-supported crowns, fixed partial dentures, or complete implant-supported dentures. Implants used were threaded titanium cylinders placed under general or local anesthesia. All surgical complications in the healing period or at second-stage surgery were noted, as were all prosthodontic complications. Results: Fourteen patients were treated with 35 implants. Three implants were lost before or at second-stage surgery, and two implants were lost after loading. These complications were observed in two patients. Implant failures and other complications were observed in two patients in the mandible because of dehiscence of the mucoperiosteal flap and infection. Some patients had developed finger or oral habits, such as excessive tongue movements, that were probably responsible for these complications. One of the patients with Down syndrome possibly had reduced resistance to infections. No major complications were observed for the other 12 patients treated. Conclusion: Strict adherence to a surgical protocol is needed for the management of patients with neurologic disabilities. It is important to inform the patient's caregiver about maintenance of good oral hygiene and the increased risk of complications caused by finger or oral habits.

Purpose: The purpose of this report was to evaluate indications for the use of removable partial dentures based on a comprehensive literature review. Materials and Methods: Using a model similar to a Delphi process, the literature relating to the indications and contraindications for the prescription of removable partial dentures was discussed by seven experienced educators in a 2.5-day workshop. Results: Evidence for indications and contraindications for the prescription of removable partial dentures is not clearly stated in the literature; however, some basic principles are defined. There appears to be a trend in favor of the use of the shortened dental arch concept or implant-supported restorations instead of conventional removable partial dentures, given the evidence that the long-term use of removable dentures is associated with increased risks of caries and periodontitis and low patient acceptance. The presence of sound abutment teeth appears to encourage the use of removable partial dentures, as the fixed partial denture alternative requires sacrifice of healthy hard tissues. When economic factors influence the decision-making process, removable partial dentures are often chosen. Conclusion: While evidence-based indications and contraindications for prescribing removable partial dentures are still lacking, major underlying principles for clinical decision making are identified.

Purpose: It is well-recognized that many institutionalized elderly persons with dementia do not wear dentures. The objective of this study was to evaluate the current status of denture use among elderly patients with dementia, in association with degree of mental impairment, to provide information relating to a decision-making process for optimal denture treatment. Materials and Methods: From August 2001 to December 2002, 101 hospitalized elderly persons in a geriatric hospital dental clinic received removable denture treatment by two certified prosthodontists. Prior to denture treatment, patient mental status was evaluated using the Mini Mental Status Examination (MMSE). Basic activities of daily living, including mobility, feeding, toilet use, dressing, and bathing, were also evaluated. Denture acceptance was determined 6 months after denture delivery. Results: Eight patients were excluded; 73 patients had accepted their dentures and 20 had not 6 months after denture delivery. The mean MMSE score for patients who did not accept denture delivery (11.7 ± 7.0) was significantly lower than that of those who did accept and wear their dentures (16.0 ± 6.8). Conclusion: The cognitive status of institutionalized elderly persons with dementia should be a criterion for clinical decision making relating to denture treatment.

Purpose: In addition to the CIE Lab color-difference formula (ΔE*_ab), advanced formulas that include weighting functions have been introduced. The objectives of this study were to determine the correlations in color differences between different shade pairs of resin composites by different color formulas, and to determine whether the weighting functions included in the advanced formulas influenced the color-difference values. Materials and Methods: Color was measured after polymerization of two resin composites in 26 shades, and color differences between shades were calculated by ΔE*_ab, CIEDE 2000 (ΔE₀₀), and DIN 99 (ΔE₉₉) formulas. Regression analyses were performed between the color differences calculated by three formulas in each group divided by the differences in color parametric factors between the pairs compared. Results: There were significant correlations between ΔE*_ab and ΔE₀₀, ΔE*ab and ΔE₉₉, and ΔE₉₉ and ΔE₀₀ (r² = .99, .89, and .90, respectively). The weighting functions in the CIEDE 2000 formula had influence on ΔE₀₀ values when differences in chroma and hue between compared pairs were great. Conclusion: Differences in parametric factors between the pairs compared influenced the correlation between ΔE*_ab and ΔE₉₉values (r² = .25 to .97). As the CIEDE 2000 formula has been proven to be better matched to observer responses and showed significant involvement of weighting functions compared to CIE Lab color difference, this formula should be considered for evaluation of the color of resin composites.

Purpose: The purpose of the present in vitro study was to examine shear bond strengths of resin composite to porcelain according to surface treatment. Materials and Methods: One hundred eight feldspathic porcelain blocks were prepared. Specimens were divided into nine surface treatment groups: sandblasting with 50- or 110-µm Al₂O₃, acid etching with hydrofluoric acid, applying silane agent, and combinations of these treatments. Microhybrid resin composite was condensed and light cured for 40 seconds on the porcelain specimens, which were then stored in distilled water at 37°C for 24 hours before mechanical testing. Results: The bond strengths were significantly different according to one-way ANOVA. The lowest bond strength was observed in the silane group (4.09 MPa); the highest bond strengths were observed with acid etching + silane (11.97 MPa) and sandblasting with 50-µm Al₂O₃ + acid etching + silane (12.34 MPa) (no significant difference between groups). Conclusion: Acid etching with 9.6% hydrofluoric acid gel or sandblasting with 50- or 110-µm Al₂O₃ particles alone did not provide adequate bond strength. Silane agent was effective in increasing the shear bond strength of resin composite to porcelain after sandblasting or acid etching. Porcelain treatment with a combination of 50-µm Al₂O₃ air abrasion, 9.6% hydrofluoric acid, and silane agent provided higher bond strengths than treatment with any of these procedures alone.

Purpose: About 50% of crowns are made because of presumed fracture risk of the tooth or restoration itself in heavily filled teeth. Agreement among clinicians to prescribe crowns is generally low and influenced by various factors, including patient-, oral-, and dentist-related factors. In dental education, agreement among teachers in different departments could promote consistent decision making. The hypothesis of the present study was that the risk to fracture of teeth restored with direct techniques is judged with a high level of agreement by dental teachers. The indication to make crowns to prevent fracture is, however, department dependent. Materials and Methods: Eight natural posterior teeth with mesio-occlusodistal (MOD) restorations were arranged in an upper and lower phantom jaw (Table 1). Variables were tooth type, jaw, and restoration material. The (pre)molars on the right side were restored with amalgam alloys; those on the left were restored with resin composites. The first premolars had MOD resin composite restorations with cusp coverage of supporting or nonsupporting cusps. Afterward, two bitewing radiographs were made.Jaws and bitewings were presented to 20 clinicians in the Operative Department and 20 in the Prosthodontic Department of the College of Dental Sciences, Radboud University of Nijmegen Medical Centre, Nijmegen, The Netherlands. They were asked to rank the teeth for risk of fracture with the consideration that other potential factors in fracture (eg, occlusal load) were equal for all teeth. Observers could additionally indicate the type of restoration to be made assuming existing restorations were worn out, purely guided by fracture risk estimation. Options were re-restoration with amalgam; re-restoration with resin composite; re-restoration with covering (additional) cusp(s); and crowning. Intraobserver agreement on this indication was assessed by five clinicians in each department following a 2-month interval. Assessments were made in the context of each department's protocol. Results: Teeth with amalgam restorations were assessed to have higher fracture risk than those with resin composite restorations (analysis of variance, P , .001; Table 1). This difference was more explicit for the Operative Department observers than for prosthodontic observers (P , .001). Additionally, operative observers assessed a higher fracture risk for the first molars (P = .001), and second premolars in the maxilla were assessed to have higher risk than mandibular ones (interaction between jaw and tooth type; P = .005). Prosthodontic observers considered the material effect greatest for premolars (interaction between material and tooth type; P , .050). Operative observers indicated 70% re-restoration with resin composite and 30% crowns, whereas prosthodontic observers more often indicated crowns (50%). This difference was significant for the four restoration types (all P , .050; Table 2). Intraobserver agreement was moderate (kappa = .51). Discussion: Results suggest that the operative teachers had more confidence in the clinical behavior of resin composite-restored teeth than did those in prosthodontics. This was reflected in the higher percentage of decisions to re-restore with resin composites instead of crowns. Noted differences between the departments, as well as moderate intraobserver agreement and relatively high standard deviations (Table 1), might interfere with consistent educational clinical decisions within a dental school. Conclusion: Fracture risk for teeth with MOD restorations was judged with low agreement by dental teachers from two clinical departments. Moreover, the indication to make a crown appears to depend substantially on the teacher's department.

Purpose: Class III malocclusion has been defined as complete anterior cross-bite and mesial relation between the mandibular and maxillary molars, and if skeletally severe may require surgical correction, adjunctive orthodontics, occlusal adjustment, and prosthodontic treatment. An alternative conservative approach precludes the surgical intervention, particularly in adult patients. This article describes the prosthodontic and endodontic management of a partially edentulous Class III malocclusion patient using removable coping-retained overdentures in both the maxillary and mandibular arches. Case Presentation: A 63-year-old man with a severe Class III malocclusion presented the following complaints: difficulty in chewing, mobile mandibular teeth, and dissatisfaction with his esthetic appearance. His medical record revealed a history of pharmacologically controlled diabetes mellitus type II. Dental and radiographic examination confirmed the presence of the mandibular left central and lateral incisors, canine, second premolar, second molar, mandibular right lateral incisor, canine, second premolar, maxillary left central and lateral incisors, canine, first premolar, and maxillary right lateral incisor and canine (Fig 1); an anterior cross-bite; loss of periodontal support around the mandibular incisors; plus mobility and gingival recession. Oral examination and cephalometric analysis confirmed a mixed dental and skeletal Class III malocclusion. Orthognathic surgery was not considered or prescribed because of the patient's age and systemic condition. Milled cast coping-retained overdentures were planned for both mandibular and maxillary arches. The labioversion of the mandibular incisors and the length and bulk of the premolar and molar teeth required endodontic treatment to permit their use as abutments for overlying denture base material. After the teeth were prepared, a definitive impression for coping fabrication was made with a custom tray using condensation putty (Zetaplus, Zhermack) and light-body silicone impression materials (Oranwash, Zhermack). After Cr-Ni metal alloy (Wiron 99, Bego) copings were adjusted, the copings were luted with glass-ionomer cement (Medicem, Promedica) (Fig 2a). The day after cementation, impressions for coping-retained overdentures were made with custom trays and medium-viscosity addition silicone impression material (Panasil Contact Plus, Kettenbach). The impressions were cast and occlusion rims made to record the patient's vertical dimension of occlusion. A bilateral balanced articulation was developed using 33-degree anatomic acrylic resin teeth (Optognath, Bayer), and maximal soft tissue coverage was used for maxillary and mandibular coping-retained overdentures. The overdenture prostheses were processed with heat-polymerizing acrylic resin (Meliodent, Heraeus Kulzer). The patient was examined 48 hours later for postinsertion adjustment and then followed on a monthly basis (Fig 2b). At the 18-month follow-up, he stated that he had no complaints with his overdentures. Conclusion: This patient's systemic and economic concerns determined the prescription of our selected protocol, which addressed and satisfied both patient- and dentist-mediated clinical management concerns.

Purpose: Loosening or fracturing of abutment or retaining screws is the main mechanical complication associated with single-tooth implants. The bearing surface of an implant and of its opposing abutment form a screw joint that must remain stable throughout the restoration's life. To reduce the incidence of screw loosening, biomechanical parameters of movement at the interface of the implant-abutment complex must be studied. Binon reports that optimal joint stability requires rotational freedom of less than 5 degrees. The present study sought to evaluate and compare the rotational freedom of external and internal hex implants and their abutment counterparts to verify if a particular measuring device is suitable and if all components are in accordance with manufacturing specifications. Materials and Methods: Five regular-diameter external hex implants and five regular-diameter internal hex implants with abutments (Conexao Sistemas de Proteses) were evaluated. To measure the rotational freedom, a device in which the implants were secured by a chuck to a table base with a degree scale was developed (Fig 1). The rotational freedom measuring device table was calibrated through geometric analysis of its scale and a calibrated protractor. A handle and needle pointer were fixed to the abutments through two opposing screw holes. Abutments were screwed to the implants using a manual torque wrench (20 Ncm). With a dynamometer, a 40-Ncm torque was applied to the abutment, and the difference between the clockwise and counterclockwise movement was recorded as rotational freedom with 0.5-degree accuracy. Measurements were taken in every possible position (three different positions, three times) and combination of implants and abutments. An optical measurement system (RAM Optical Instrumentation) with Auto MAP X-Y-Z software (Measurement Analysis Program) was used to measure both implant and abutment hexagons with 0.0001-mm accuracy. Three measurements were taken per hexagon, corresponding to the distance of its opposing boundary lines. Data were subjected to analysis of variance (P , .05) to determine statistical significance between internal and external hex implants. Mean values and standard deviations were recorded. Results: Mean rotational freedom was 5.5 ± 1.9 degrees for internal hex implants, which presented rotational freedom of between 3 and 5 degrees in 58.67% of the combinations; 41.33% showed rotational freedom higher than 5 degrees (recorded range 3.5 to 11.0 degrees). Mean rotational freedom was 2.9 ± 0.3 degrees for external hex implants. All external hex implant configurations presented rotational freedom lower than 5 degrees; 93.33% showed rotational freedom lower than 3 degrees (recorded range 2.5 to 3.5 degrees). Statistically significant differences were found between groups (P , .05). Conclusion: In this pilot study, internal hex implants presented more rotational freedom than external hex implants. All samples were in accordance with the manufacturing specifications. The reported measuring device appears suitable to analyze rotational freedom and will be used in further studies with other implant systems. The number of implants and abutments used in this pilot study is not large enough to draw more precise conclusions.