Evaluation of the relationship between bruxism and premature occlusal contacts.

AIM: This study evaluates the relationship between occlusal interferences and premature contacts and bruxism by determining the relationship between unassisted and assisted nonworking interferences. MATERIALS AND METHODS: In this study, 60 subjects (14 males and 46 females) that consisted of 30 bruxers (7 males, 23 females) and 30 nonbruxers (7 males, 23 females) were selected after completion of a questionnaire based on the exclusion criteria. Occlusal interferences in the centric relation and eccentric movements in the two groups were evaluated and recorded. Data were analyzed by SPSS software (version 16) using the Chi-square and paired t-tests. RESULTS: The results showed a statistically significant relationship between bruxism and nonworking interferences (p < 0.05). There was no statistically significant relationship in the centric relation and other eccentric movements (p > 0.05). The number of assisted nonworking occlusal contacts was more than unassisted nonworking occlusal contacts. CONCLUSION: According to the results of this study, there is a relationship between certain types of occlusal interferences (nonworking interferences) and bruxism. Hence, it would be useful to examine occlusal contacts in bruxing patients to eliminate probable causative or contributing occlusal factors. Both assisted and unassisted nonworking occlusal contacts should be evaluated. CLINICAL IMPLICATION: Bruxism is an oral habit that consists of involuntary rhythmic or spasmodic nonfunctional gnashing, grinding or teeth clenching, other than chewing movements by the mandible. Bruxism may lead to occlusal trauma, tooth wear, fracture of the teeth and fillings, and hypertrophy of the masticatory muscles. Treatment of bruxism needs a correct diagnosis. Therefore, it is useful to determine the relationship between occlusal interferences and bruxism in order to prevent its development by adjusting for these interferences.

Prosthodontic rehabilitation for total glossectomy with a magnetic detachable mandibular tongue prosthesis: a clinical report.

Total glossectomy can result in significant functional impairments in mastication, swallowing, and speech. In addition to these functional problems, severe psychological problems may follow complete loss of the tongue. Placement of a mandibular tongue prosthesis obturates this large defect, increases the patient's ability to produce intelligible sounds, and assists with a return to a normal diet. Prosthetic rehabilitation can also improve the user's appearance and psychosocial adjustment. This clinical report describes a magnetically attached two-piece tongue prosthesis used to treat a patient who underwent total glossectomy.

The Effects of Denture Cleansing Solutions on the Retention of Attachments of Implant Supported Overdentures.

STATEMENT OF THE PROBLEM: Implant-retained overdenture can improve the stability of dentures and prevent bone loss. Overdenture-wearing patients need special hygiene care. PURPOSE: The aim of this study was to evaluate the effects of various denture cleansers on the retention of Dio orange O-rings. METHOD AND MATERIALS: In this experimental study, 40 Dio orange O-rings were divided into 4 groups (10 O-rings each) and each group was soaked for equivalent of 6 months in the following solutions: 5.25% NaOCl (1:10 dilution), Corega cleanser tabs, Professional cleanser tabs and water (as the control group). After 6 months, O-rings were tested for 2inch/minutes of tensile force. The peak load-to-dislodgement was recorded. Data were imported to SPSS18 and were analyzed by One-Way ANOVA and Tukey HSD test (p≤ 0.05). RESULTS: Denture cleansing solutions have significant effects on the reduction of retentive value of O-rings (p≤ 0.001). Corega tabs caused the reduction of 15.7% (9.91±0.53 N) in the retentive value of O-rings and Professional tabs caused 15% (10.00±0.86 N). NaOCl caused significant decrease (48%) in retentive value of O-rings (6.10±0.91 N in comparison with the control group (11.76±1 N). CONCLUSION: This in-vitro study demonstrated that the retention of O-rings was affected when soaked in cleansing solutions. NaOCl caused more reduction in retentive value compared to effervescent cleansers and would not be recommended for cleansing O-rings. These results should be interpreted clinically and the role of other factors in the retention of O-rings should be considered in order to recommend the best cleanser for O-ring overdentures.

The effect of porcelain firing and type of finish line on the marginal fit of zirconia copings.

STATEMENT OF THE PROBLEM: Although all-ceramic restorations are broadly used, there is a lack of information concerning how their fit is affected by fabrication procedure and marginal configuration. PURPOSE: The purpose of this study was to evaluate the marginal fit of zirconia CAD/CAM ceramic crowns before and after porcelain firing. The influence of finish line configuration on the marginal fit was also evaluated. MATERIALS AND METHOD: Twenty standardized zirconia CAD/CAM copings were fabricated for chamfer and shoulder finish line designs (n=10). The marginal fit of specimens was measured on 18 points, marked on the master metal die by using a digital microscope. After the crowns were finalized by porcelain veneering, the measurements of marginal fit were performed again. The means and standard deviations were calculated and data were analyzed using student's t-test and paired t-test (α=0.05). RESULTS: There were significant differences between marginal fit of chamfer and shoulder finish line groups before and after porcelain firing (p= 0.014 and p= 0.000, respectively). The marginal gap of copings with shoulder finish line was significantly smaller than those with chamfer configuration (p= 0.000), but there were no significant differences between the two marginal designs, after porcelain firing (p= 0.341). CONCLUSION: Porcelain veneering was found to have a statistically significant influence on the marginal fit of zirconia CAD/CAM crowns. Both margin configurations showed marginal gaps that were within a reported clinically acceptable range of marginal discrepancy.