Comparison of two computerized occlusal analysis systems for indicating occlusal contacts

PURPOSE

The purpose of this study was to compare the performance of Accura to that of the T-scan for indicating occlusal contacts.

MATERIALS AND METHODS

Twenty-four subjects were selected. Their maxillary dental casts were scanned with a model scanner. The Stereolithography files of the casts were positioned to align with the occlusal plane. Occlusal surfaces of every tooth were divided into three to six anatomic regions. T-scan and Accura recordings were made during two masticatory cycles. The T-scan and Accura images were captured at the maximum bite force and overlapped to the cast. Photographs of interocclusal records were used as the reference during overlap. The occlusal contacts were counted to compare the T-scan and Accura. McNemar's test was used for statistical significance and the corresponding P-values were calculated from a chi-square distribution with one degree of freedom. The accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of Accura were calculated relative to the T-scan values as a control.

RESULTS

No statistical differences (P>.05) were found between the T-scan and Accura methods. The accuracy of Accura was 75.8%, sensitivity was 82.1%, specificity was 60.1%, PPV was 82.9%, and NPV was 60.1%.

CONCLUSION

Accura could be another possible option as a computerized occlusal analysis system for indicating occlusal contacts at maximum intercuspation.

Effect of head posture on tooth contacts in dentate and complete denture wearers using computerized occlusal analysis system

Purpose:

The purpose of the study was to assess and compare the occlusal contacts in dentate and edentulous patients wearing complete denture with varying head posture.

Materials and Methods:

Ad hoc sampling of 30 subjects (15 dentate and 15 edentulous) based on inclusion and exclusion criteria was done. Subjects were divided into two groups: dentate and edentulous. Each group was further divided into two subgroups based on two head postures-upright 90° and ventroflexed 30°. For recording of every posture, a new sensor was used, and the subject was asked to clench on the sensor in maximum intercuspation position at the two head postures.

Results:

Data were summarized as mean ± standard error and compared by Student's t-test using SPSS software (windows version 17.0 IBM corporation, New York, USA). A statistically significant correlation between head posture and contact area was found in dentate and denture wearers, i.e., tooth contact area varies with head posture.

Conclusion:

It was concluded that the occlusal contacts vary at different head posture in dentate as well as in denture wearers. With ventroflexion, the number of tooth contact decreased as compared to upright-erect position in both groups. Clinical implication - since the number of tooth contacts varies with varying head postures, it is recommended that the balancing of the contacts should be done at varying head postures.