The International Journal of Prosthodontics, 06/2005

Purpose: The aim of this report is to present the implant and clinical outcomes of an immediate-loading protocol of TiUnite implants with mandibular overdentures in edentulous patients. Materials and Methods: Two groups of edentulous patients were selected. Thirty-five consecutively treated patients received 70 immediately loaded TiUnite implants and 69 Brånemark implants as backup (1 patient received 1 Brånemark implant). The control group was a historical cohort that comprised 42 patients who received 111 Brånemark implants. All overdentures were supported by a resilient bar mechanism. Implant and clinical outcomes, including maintenance events for the first year, were recorded. Results: Implant success rates were in excess of 95% with both protocols. Immediately loaded implants had less bone loss than did implants loaded with the conventional protocol (Mann-Whitney U test; P = .001). Patients in the immediate-loading group required more prosthodontic maintenance, consisting of overdenture remakes and laboratory relining of prostheses (Chi-square test; P .05). Of note, 74% of patients in the immediate-loading group needed a reline to improve the denture seal around the bar housing (Chi-square test; P .05). Conclusion: The favorable implant and bone level outcomes with immediate loading attest to its biologic success. The prosthetic maintenance encountered in the immediate-loading group does not negate the clinical potential of the treatment but rather suggests that the protocol may benefit from modifications.

Purpose: The purpose of this study was to determine a baseline value of tongue pressure on the palatal region in normal subjects that could then be used to assist in fabrication of a palatal augmentation prosthesis (PAP). Materials and Methods: A tongue-pressure measurement system with 36 rubber pressure sensors was constructed for this study. This system was applied to 16 normal subjects, and the tongue pressure on the palatal region was measured when they were swallowing. Results: The maximum tongue pressures seen during swallowing were 85.0 g/cm2 in the early stage, 95.0 g/cm2 in the middle stage, and 93.0 g/cm2 in the late stage. The average maximum tongue pressure throughout swallowing was 91.0 g/cm2. The tongue pressure in the early stage ranged from 3.37 g/cm2 to 8.74 g/cm2. A significant difference was found between the anterior and the posterior regions and between the central and the posterior regions. The value in the middle stage ranged from 5.32 g/cm2 to 10.22 g/cm2. Significant differences were found between the anterior and the posterior regions and between the central and the posterior regions. Values in the late stage ranged from 6.80 g/cm2 to 7.91 g/cm2. Conclusion: The average maximum tongue pressure against the palate of approximately 90 g/cm2 suggests that a PAP sufficient for swallowing should be strong enough to withstand this amount of pressure. The device is also useful to check for variations in the tongue contact area during trial of the prosthesis.

Purpose: Evaluation of treatment outcome is important in maxillofacial rehabilitation. Although eating is one of the oral functions that most strongly influences patients' quality of life, only a few reports exist on the objective assessment of swallowing for maxillectomy patients. The purpose of this study was to identify changes in the swallowing ability of maxillectomy patients when wearing obturator prostheses through the use of an objective clinical assessment. Materials and Methods: The swallowing ability of 38 postmaxillectomy patients consecutively treated with obturator prostheses was objectively evaluated with the "water-drinking test" that was developed for the assessment of dysphagia patients after cerebrovascular disease. In this test, the subjects were instructed to drink 30 mL of water in one swallow. The profile was evaluated with the combination of the time required for drinking the water and the incidence of cough reflex. Statistical analysis was performed using the Wilcoxon signed-rank test, the paired t test, and the Chi-square test with StatView 5.0 for the Macintosh. Results: Performance improved significantly when the patients wore prostheses (P = .0026, Wilcoxon signed-rank test). The mean drinking times without and with prostheses were 8.2 ± 6.3 s and 5.0 ± 3.5 s, respectively. Drinking time was shortened significantly when the prosthesis was worn (P = .0002, paired t test). The assessment of behavior and episodes revealed that the swallowing ability of the maxillectomy patients was significantly improved when a prosthesis was worn (P = .0002, Chi-square test). Conclusion: The swallowing ability of maxillectomy patients was quantitatively and qualitatively improved with obturator prostheses.

Purpose: To evaluate the dimensional contour variations of acrylic resin denture bases before and after storage in water. Materials and Methods: The fit of 40 bases was evaluated by measuring the thickness of a layer made with silicone placed between the bases and the casts. The measurements were repeated on a new set of silicone layers after having stored the bases in water for 42 days. Results: Significant differences were found both for the maxillary and the mandibular bases. Conclusion: Water sorption had an important effect on the contour of the prosthetic bases.

Purpose: Little is known about why people accept or refuse oral implant treatment. The purpose of this study was to assess edentulous subjects' acceptance or refusal of free implants to retain mandibular dentures, and to evaluate factors that might predict those who are more likely to choose implants. Materials and Methods: One hundred one volunteers completed questionnaires about their background, satisfaction with conventional dentures, oral health-related quality of life, and preference for implants. Results were analyzed using Pearson chi-square tests and logistic regression. Results: While 79% of volunteers accepted and 21% refused an initial offer of free implants, a number of them changed their minds, leaving 64% who wanted implants and 36% who did not want them. The most common reason for choosing implants was anticipation of improved mandibular denture stability or security (73%), while the most common reason for refusal was concern about surgical risks (43%). A logistic regression model identifying those who complained of poor chewing function, poor speech, pain, and dissatisfaction with appearance improved the prediction of those who wanted implants from 64% to 80%. Conclusion: When cost was removed as a factor, more than one third (36%) of the older, edentulous participants in this study ultimately refused an offer of free implants to retain their mandibular dentures. Poor chewing function, poor speech, pain, and dissatisfaction with appearance were the most important factors in predicting who would choose implants.

Purpose: Many restorative systems have become commercially available that are based on fiber-reinforced polymers (FRP) for production of fixed partial dentures. However, the clinical documentation of their use has not been systematically reviewed and critically appraised. This systematic review aimed to identify the scientific documentation of all commercially available products within this material group. Materials and Methods: MEDLINE was searched for all clinical and laboratory studies on FRP, and papers were browsed to identify product names. Moreover, the Internet was searched to find manufacturers of FRP products. Also, several large trade exhibitions were visited to identify products and manufacturers. All papers that included any data from a clinical setting of an identifiable product were critically appraised. Each product was categorized according to the scientific clinical documentation of their intended clinical use. Results: Eleven commercial products were identified. The scientific clinical documentation of these products varied markedly, but was generally poor. No randomized controlled trials have been carried out on FRPs versus, eg, conventional treatments, nor are any long-term cohort studies available. None of the products demonstrate good evidence for usage as a technical solution to permanently replace lost teeth. Conclusion: The use of FRP for fixed partial dentures must still be regarded as experimental.

Purpose: The purpose of this preliminary prospective study was to evaluate the clinical outcome of crown-retained and inlay-retained fixed partial dentures (FPDs) made from a new lithium-disilicate glass-ceramic (IPS e.max Press, Ivoclar Vivadent). Materials and Methods: Eighty-one 3-unit FPDs were placed in 68 patients. The FPDs replaced teeth in the anterior (8%) and posterior region (92%). All teeth were prepared according to a standardized protocol. The size of the proximal connector of the FPDs was 12 mm2 (anterior) or 16 mm2 (posterior), respectively. Crown-retained FPDs were cemented either with glass ionomer (n = 20) or resin composite (n = 16), while all inlay-retained FPDs (n = 45) were cemented with resin composite. Initial follow-up was performed at 6 and 12 months and annually thereafter. Results: The mean observation periods were 48 months (for crown-retained FPDs) and 37 months (for inlay-retained FPDs). None of the crown-retained FPDs failed during the observation period, while 6 inlay-retained FPDs (13%) had to be replaced. Six cases failed because of debonding (n = 3) or a combination of debonding and fracture (n = 3). During the observation period, 2 patients died and the status of another 5 patients is unknown. The 4-year survival rate according to Kaplan-Meier was 100% for crown-retained FPDs and 89% for inlay-retained FPDs. The differences between the groups were statistically significant. Conclusion: Crown-retained 3-unit FPDs made from a new glass-ceramic have a significantly better outcome up to 5 years than inlay-retained 3-unit FPDs over the observation period.

Purpose: The aim of this prospective pilot study was to investigate differences in changes in implant stability and crestal bone height between loaded and unloaded dental implants at 4 months after placement. Materials and Methods: In the test group, 20 implants were placed in the anterior region of the mandible in 10 patients. They were connected with a Dolder bar within 10 days and placed into function immediately. In the control group, 21 implants were placed in the anterior region of the mandible in a 2-stage procedure in 12 patients. The implants used were TiUnite, with a diameter of 3.75 mm and a minimum length of 10 mm. Resonance frequency analysis was used to measure differences in implant stability, with the implant stability quotient (ISQ) as the unit of measure. An instrument was developed to measure the bone level directly. On a customized abutment, a probe with a stopper measured the distance between the shoulder of the instrument and the bone. Measurements were made on all 4 sides of each implant. Intra- and interexaminer variability showed an agreement that was greater than 99% (kappa > 0.99) for both sets of measurements. Results: In the early loading group, the mean change in ISQ was -0.08 ± 0.77 and the mean bone loss from buccal, mesial, distal, and lingual sites was 0.69 ± 0.15 mm. In the unloaded group, the mean change in ISQ was 1.33 ± 1.65 and the mean bone loss from buccal, mesial, distal, and lingual sites was 0.53 ± 0.18 mm. There was no statistically significant difference across the 2 treatment groups. The changes in bone height at buccal and lingual sites were not statistically different from the changes at mesial and distal sites. When gender was included as a factor, the changes in stability and bone loss were statistically smaller among female patients than among male patients. Conclusion: In this preliminary study, early loading did not show an influence on bony crest height and stability in TiUnite implants placed in the anterior mandible during the first 4 months of service.

Purpose: To determine whether intercommissural width is a reliable guide for the selection of maxillary denture teeth width. Materials and Methods: Casts were made of 160 subjects from 4 different racial groups. Locations of intercommissural width landmarks (the corners of the mouth) were made on the subjects and transferred to the casts. The distances between the corners of the mouth and the distal of the canines were measured on the casts and compared. Results: A weak correlation was found between the distal of the canines and the distance between the corners of the mouth in the 4 racial groups. Conclusion: The use of the corners of the mouth for the selection of artificial teeth is generally inaccurate.

Purpose: This cross-sectional study evaluated the relationship between attrition and diverse variables in 390 Mexican adolescents aged 14 to 19 years. Materials and Methods: An ordinal scoring system was used to describe the severity of attrition. Results: Attrition prevalence was 33.3% and was associated with older age, presence of defective restorations, Class II malocclusion, and perception of stress level. Conclusion: Our results suggest that attrition is present in 1 of every 3 adolescents.

Purpose: To test whether microwave oven irradiation can disinfect gypsum casts in compliance with current disinfection requirements, and to determine whether this procedure would be as effective as a validated method of chemical disinfection of impressions. Materials and Methods: In 2 in vitro experiments, samples of 5 irreversible hydrocolloid impressions of a disinfected acrylic resin model were contaminated with suspensions of recommended test organisms Staphylococcus aureus and Pseudomonas aeruginosa, respectively. In 1 in vivo experiment, 10 impressions were made of 10 subjects. All impressions were poured and the resulting casts cut in 2 halves. One half of each cast was exposed to 5 minutes of irradiation in a microwave oven at 2,450 MHz and 900 W. The other halves were left untreated as controls. In a second in vivo experiment, 10 impressions were disinfected by immersion in a 0.07% solution of NaOCl at pH of about 10 for 3 minutes, and then poured. All casts were incubated aerobically in Bacto tryptic soy broth at 37°C for 6 hours and assessed for bacterial growth by counting colony-forming units per milliliter (cfu/mL) of the culture. The results were analyzed using the Wilcoxon signed-rank test. Results: Untreated gypsum casts showed cfu/mL counts with a median log value of 6, while microwave-irradiated ones had median cfu/mL counts of 0. Casts poured from chemically disinfected impressions demonstrated cfu/mL counts with a median log value of 4. Conclusion: Under the described conditions, microwave-irradiated gypsum casts satisfy current disinfection requirements, but gypsum casts poured from chemically disinfected impressions do not.