The International Journal of Prosthodontics, 05/2007

The aim of this study was to determine if the bactericidal effect of microwaving gypsum casts is maintained at maximum capacity of the oven (16 casts). Batches of 8 and 16 gypsum casts made from in vivo impressions were divided in half. One half of each cast was microwaved at 900 W for 5 minutes. The remaining halves were left untreated. When assessed for bacteriological growth, the median cfu/mL of the untreated casts was between 105 and 106, while the microwaved casts showed a cfu/mL of 0, indicating that microwaving as described will disinfect gypsum casts even at maximum capacity of the oven.

The aim of this study was to compare the surface roughness produced by polishing 2 all-ceramic materials after surface conditioning. Air particle abrasion (APA) with 25-µm aluminum oxide, 9.6% hydrofluoric acid (HFA,) and APA + HFA were applied for ceramic surface conditioning. Subsequently, the ceramics were subjected to 3 polishing techniques: polishing kit, polishing paste, and polishing kit + polishing paste. Surface roughness (Ra) was evaluated profilometrically. The highest DRa values were obtained with the polishing kit and polishing kit + paste for the APA + HFA groups. No significant differences were observed among the polishing paste groups. Combining a polishing kit and polishing paste produced the smoothest ceramic surfaces.

Purpose: Surgical treatment of malignancies in the oral cavity and subsequent radiotherapy often result in an oral condition unfavorable for prosthodontic rehabilitation. This study assessed the quality of life related to oral function in edentulous head and neck cancer patients following oncology treatment of malignancies in the lower region of the oral cavity. Materials and Methods: Patients treated between 1990 and 2000 with surgery and radiotherapy for a squamous cell carcinoma in the oral cavity who were edentulous in the mandible and had been treated with a conventional, non-implant-retained denture received an invitation for a clinical check-up (clinical assessment, questionnaires regarding oral function and quality of life). Results: Sixty-seven of the 84 patients who fulfilled the inclusion criteria were willing to participate in the study. The mean irradiation dosage that these patients had received in the oral region was 61.8 ± 5.4 Gy. Half of the patients (n = 33) were not very satisfied with their prostheses; they wore their mandibular prostheses at most a few hours per day. It was concluded from the clinical assessment that two thirds of the patients (n = 44) could benefit from an implant-retained mandibular denture. Analyses of the questionnaires revealed no significant associations between functional assessments, quality of life, and parameters such as size of the primary tumor, location of the primary tumor, and different treatment regimes. Despite cancer treatment, the patients reported a rather good general quality of life. Conclusions: Sequelae resulting from radiotherapy probably dominate oral function and quality of life after oncology treatment. In two thirds of the patients, improvement of oral function and related quality of life would be expected with the use of an implant-retained mandibular denture.

Purpose: This study aimed to investigate the association of masticatory performance with oral health-related quality of life in independently living elderly Japanese subjects. Materials and Methods: The study sample consisted of 1,028 independently living people over the age of 60 years. Masticatory performance was determined by the concentration of dissolved glucose obtained from test gummy jellies, which are the standardized food developed for measuring masticatory performance. The short-form Oral Health Impact Profile (OHIP-14) and Geriatric Oral Health Assessment Index (GOHAI) were used to measure the impact of oral conditions on oral health-related quality of life. Results: Subjects with lower masticatory performance had significantly higher total OHIP-14 and GOHAI scores (15.0 ± 9.0 and 14.5 ± 9.2, respectively) than their counterparts (10.0 ± 7.5 and 11.3 ± 7.1, respectively) (P .01). Logistic regression analyses showed that after controlling for age, gender, self-perceived general health, satisfaction with financial status, and number of teeth, a higher GOHAI score was significantly related to lower masticatory performance (P = .001; odds ratio: 0.56; 95% CI: 0.40 to 0.79). A higher OHIP-14 score was associated with lower masticatory performance but at a level below statistical significance (P = .096; odds ratio: 0.75; 95% CI: 0.53 to 1.05). Conclusion: It is suggested that masticatory performance is an important factor influencing the quality of life in independently living, relatively healthy elderly Japanese subjects

The purpose of this descriptive study was to analyze the behavior of a bicomponent custom-made zirconia abutment used with an internal connection implant system. The microscopic marginal fit and specific mechanical characteristics of 20 titanium platform and zirconia abutment complexes were evaluated. Scanning electron microscope analysis showed mean values of 10.03 µm for the horizontal gap and 4.419 µm for the vertical gap for the components. The traction test revealed a mean maximum load value of 190 N, whereas the bending test showed a mean maximum load value of 436 N.

Purpose: This study evaluated the clinical performance of cemented customized zirconia abutments. Additionally, the marginal fit between the selected implant components was measured and the clinical gingival response was monitored. Materials and Methods: Twenty-five patients were consecutively selected for a prospective study of 30 implant-supported single-tooth restorations. Customized titanium post and zirconia abutment complexes were prepared, and scanning electron microscopy (SEM) analysis was used to study bicomponent marginal gaps. The abutments were screwed onto the implants and restored with all-ceramic crowns. Plaque and gingival indices were recorded at 6 monthly intervals over a 36- to 44-month period. Results: SEM analysis showed mean marginal gaps of 10.161 µm (SD: 0.7) horizontally and 4.783 µm (SD: 0.67) vertically. Abutment fractures and screw loosening were neither reported nor observed throughout the clinical observation period. Mean Plaque Index scores were 0.57 (SD: 0.32) on abutments and 0.74 (SD: 0.34) on teeth, while mean Gingival Index scores were 0.54 (SD: 0.2) on abutments and 0.72 (SD: 0.3) on teeth. Conclusions: These preliminary results suggest that metallic-zirconia abutments may be comparable to currently available esthetic implant abutments.

The aim of this study was to evaluate acidic erosion of 7 luting cements. Erosion was evaluated via immersion in 0.1 M aqueous sodium lactate/lactic acid buffer (pH = 2.74 and 4.0, respectively). The rank order of cement loss was as follows: Phosphate Cement > Fuji I hand-mixed = Fuji I encapsulated > Ketac Cem > Calibra = Fuji Plus = Variolink Ultra. Cement type, pH, and time had statistically significant effects. Water-based cements exhibited more erosion compared to resin-based cements, and the latter underwent hygroscopic expansion caused by water sorption.

This study aimed to evaluate the effect of gender, antagonistic teeth, and type of denture on clinical wear of denture teeth. Wear measurements were made on gypsum replicas of 204 posterior denture teeth after 6 months using an optical 3-dimensional profilometer. Data were analyzed using univariate and mixed regression procedures. The mean wear of all denture teeth was -20.5 µm (± 14.6). Males demonstrated significantly higher wear than females. Interactions of the variables "gender" and "type of denture" and "antagonist material" and "type of denture" also showed significant influences on wear. The results indicate that some clinical parameters may affect wear of denture teeth.

Purpose: This randomized parallel-group clinical pilot study aimed to compare the clinical outcome of prefabricated rigid titanium to glass fiber endodontic posts when luted with self-adhesive universal resin cement. Materials and Methods: Ninety-eight patients in need of postendodontic restoration were assessed for eligibility. Ninety-one patients met the selection criteria and were randomized and allocated to 2 intervention groups. Forty-five participants were treated using a titanium post and 46 participants received a glass fiber post, each in combination with composite core buildups for postendodontic restoration. All posts had a diameter of 1.4 mm and a length of 13 mm and were cemented 8 mm within the root canal with self-adhesive universal resin cement. A circumferential ferrule of 2 mm was always provided. Surgical crown lengthening was necessary in 13 cases. Patients were observed in intervals of 3, 6, 12, 24, and 36 months after post placement. Results: After 24 to 36 months (mean ± SD: 27.9 ± 5.6) of observation following post placement, 1 tooth was extracted because of changes of the prosthetic treatment plan. No failures were observed among the 88 patients with follow-up data. Conclusions: Both titanium and glass fiber reinforced composite posts result in successful treatment outcomes after 2 years. The material combination used seems to be appropriate in the short term for cementing endodontic posts, irrespective of the post material.

The aim of this study was to determine the susceptibility of Candida isolates obtained from patients with Candida-associated denture stomatitis to 4 antimycotics. Antifungal susceptibility was assayed using the ATB-Fungus-2INT test. A total of 120 Candida strains were identified: C albicans (59.2%), C glabrata (20%), C tropicalis (12.5%), and C parapsilosis (8.3%). Amphotericin B, 5-fluorocytosine, fluconazole, and itraconazole were effective against 100%, 98.6%, 88.7%, and 87.3% of C albicans and 79.6%, 77.6%, 71.4%, and 79.6% of the other Candida strains, respectively. The identification of candidal strains and determination of their susceptibility to antifungals may improve the management of Candida-associated denture stomatitis.

Purpose: To describe self-reported oral health status before and after treatment in patients treated with fixed, removable, and complete dentures. Materials and Methods: Subjects were a convenience sample of 119 prosthodontic patients (patients treated with fixed prostheses (n = 61), removable dentures (n = 48), and complete dentures (n = 10); mean age: 57.3 ± 15.6 years; 47% women). Self-reported oral health status before and 1 month after treatment was measured with a 5-point question (responses ranging from "excellent" to "poor") frequently used in epidemiologic studies and health services research. Pretreatment and posttreatment self-ratings of oral health were compared with the findings from a national general population sample (n = 2,016; age: 16 to 79 years) categorized by their denture status. Change of oral health status was evaluated using Wilcoxon matched pairs signed ranks test. Results: "Excellent" or "very good" ratings were observed for 4% of the patients at baseline and for 16% of the patients at follow-up, which was identical to the prevalence of these ratings in the general population for subjects with removable dentures (16%) and better than for complete dentures wearers (13%). The change from pretreatment to posttreatment self-reported oral health status was statistically significant (P .001). Substantial differences in change patterns among groupings of prosthodontic therapies (fixed, removable, or complete dentures) were not observed. Conclusions: Self-reported oral health status improved considerably comparing pretreatment and posttreatment status. Single questions describing the overall situation of perceived oral health or its changes may provide simple and easy-to-interpret information about the impact of prosthodontic treatment

Purpose: Switching from smooth to myceliated colonies, a virulent trait of Candida albicans, may be implicated in Candida-associated denture stomatitis. The purpose of this study was to verify the relationship between the presence of denture stomatitis and the frequency of myceliated colonies of C albicans isolates in denture wearers. Prevalence of denture stomatitis and influence of putative risk factors were also investigated. Materials and Methods: Demographic and clinical data concerning oral and general health, smoking, denture status, diet, and hygiene habits of 40 complete maxillary denture wearers were collected from an autoevaluation questionnaire and oral examination. Detection of C albicans in denture plaque and evaluation of hairy phenotype colonies were carried out on low nutrient media. Eleven subjects were followed-up at 1 month and 3 months after delivery of a new prosthesis. Results were statistically analyzed. Results: Prevalence of denture stomatitis was 77.5%. No statistically significant relation was found between presence of stomatitis and frequency of myceliated colonies of C albicans or presence of yeast. However, the study confirmed a statistically significant difference between Newton types IA and IIB stomatitis in relation to yeast colony-forming units, which were more than 300 times higher in type IIB. A direct relationship was observed between the presence of C albicans and nocturnal denture use (P = .01) and an inverse relation was observed with brushing of the palate (P = .03). Conclusion: The ability of C albicans strains isolated from dentures to produce myceliated colonies may not be directly involved in denture stomatitis.

The purpose of this clinical report is to present a surgical and prosthodontic reconstructive protocol for 20 patients who underwent maxillary resection following malignancy to the head and neck region. This protocol was developed over a period of 7 years while treating a series of 20 maxillary resections due to oncology. Patients were reconstructed prosthodontically using fixed-removable overdentures or fixed prostheses, with and without separate obturators. The treatment protocol includes a comprehensive diagnostic phase, resection surgery with immediate implant placement and temporary obturation, post resection evaluation, and prosthodontic rehabilitation. Treatment periods ranged from 6 to 96 months and success was evaluated using strict clinical, radiologic, esthetic, and functional criteria. Postsurgical radiology was undertaken at 6 monthly intervals. Almost all maxillary defects resulting from anatomic disruption of the maxillofacial complex can be well rehabilitated functionally and esthetically using this protocol in conjunction with standard implantology and fixed/fixed-removable prosthodontic principles. This protocol simplifies the rehabilitation and management of these defects by reducing surgical intervention, hosptilization, postoperative morbidity and treatment time, and prosthodontic procedural complications.

This study aimed to compare the microtensile bond strength of resin cement to alumina-reinforced feldspathic ceramic submitted to acid etching or chairside tribochemical silica coating. Ten blocks of Vitadur-a were randomly divided into 2 groups according to conditioning method: (1) etching with 9.6% hydrofluoric acid or (2) chairside tribochemical silica coating. Each ceramic block was luted to the corresponding resin composite block with the resin cement (Panavia F). Next, bar specimens were produced for microtensile testing. No significant difference was observed between the 2 experimental groups (Student t test, P > .05). Both surface treatments showed similar microtensile bond strength values.

The objective of this study was to assess whether a periodontal probe measurement could be used to obtain a predictable reproduction of the buccal shelf areas in mandibular dentures. One hundred patients were measured for the anterior, middle, and posterior width of the buccal shelf with a periodontal probe. This measurement was then compared with that of the corresponding portion of the existing denture. At each portion, there were statistically significant differences in the width of the buccal shelf and that of the corresponding portion of the existing denture from dental clinics of general dentists. The periodontal probe could be used to measure the width of the buccal shelf to obtain a predictable reproduction of the buccal shelf areas in mandibular dentures.

Purpose: The objective of this study was to use an oral stereognosis test to evaluate possible intraoral/sensorimotor causes in patients with a psychologic diagnosis of psychogenic prosthesis incompatibility, and to evaluate possible correlations between oral stereognosis and the psychologic diagnostic tools Symptom Checklist-90-R (SCL-90-R) and Center of Epidemiological Studies Depression Scale (CES-D). Materials and Methods: The study cohort comprised 83 patients with complete dentures fabricated according to a standardized protocol. Twelve patients diagnosed with psychogenic prosthesis incompatibility (11 women, 1 man) using the SCL-90-R and CES-D scales in a previous study and a group of 24 randomly selected control subjects (14 women, 10 men) underwent an oral stereognosis test with 10 neutral-tasting plastic test specimens with a maximum edge length of 8 mm in 2 test cycles. Results: The results revealed no significant differences in oral stereognostic ability between patients with diagnosed psychogenic dental prosthesis incompatibility and the control patients. The patients in the test group expressed clear dissatisfaction with their dentures. No correlation was found between oral stereognostic ability and the SCL-90-R or CES-D values. Conclusions: This study is the first to use oral stereognosis tests for patients with psychologically diagnosed psychogenic dental prosthesis incompatibility. The diagnosis of psychogenic prosthesis incompatibility by the SCL-90-R and CES-D scales is affirmed by the lack of correlations between the functional/anatomic aspects of oral stereognostic ability, psychologic diagnostic tools, and the clinical picture of psychogenic prosthesis incompatibility. Thus, psychogenic prosthesis incompatibility can be classified more explicitly as a psychosomatic disorder.