Systematic assessment of the various controversies, difficulties, and current trends in the reestablishment of lost occlusal planes in edentulous patients

Prediction accuracy of incisal points in determining occlusal plane of digital complete dentures

PURPOSE

This study aimed to predict the positional coordinates of incisor points from the scan data of conventional complete dentures and verify their accuracy.

MATERIALS AND METHODS

The standard triangulated language (STL) data of the scanned 100 pairs of complete upper and lower dentures were imported into the computer-aided design software from which the position coordinates of the points corresponding to each landmark of the jaw were obtained. The x, y, and z coordinates of the incisor point (XP, YP, and ZP) were obtained from the maxillary and mandibular landmark coordinates using regression or calculation formulas, and the accuracy was verified to determine the deviation between the measured and predicted coordinate values. YP was obtained in two ways using the hamular-incisive-papilla plane (HIP) and facial measurements. Multiple regression analysis was used to predict ZP. The root mean squared error (RMSE) values were used to verify the accuracy of the XP and YP. The RMSE value was obtained after cross-validation using the remaining 30 cases of denture STL data to verify the accuracy of ZP.

RESULTS

The RMSE was 2.22 for predicting XP. When predicting YP, the RMSE of the method using the HIP plane and facial measurements was 3.18 and 0.73, respectively. Cross-validation revealed the RMSE to be 1.53.

CONCLUSION

YP and ZP could be predicted from anatomical landmarks of the maxillary and mandibular edentulous jaw, suggesting that YP could be predicted with better accuracy with the addition of the position of the lower border of the upper lip.

Virtual Dental Articulation Using Computed Tomography Data and Motion Tracking

Dental articulation holds crucial and fundamental importance in the design of dental restorations and analysis of prosthetic or orthodontic occlusions. However, common traditional and digital articulators are difficult and cumbersome in use to effectively translate the dental cast model to the articulator workspace when using traditional facebows. In this study, we have developed a personalized virtual dental articulator that directly utilizes computed tomography (CT) data to mathematically model the complex jaw movement, providing a more efficient and accurate way of analyzing and designing dental restorations. By utilizing CT data, Frankfurt's horizontal plane was established for the mathematical modeling of virtual articulation, eliminating tedious facebow transfers. After capturing the patients' CT images and tracking their jaw movements prior to dental treatment, the jaw-tracking information was incorporated into the articulation mathematical model. The validation and analysis of the personalized articulation approach were conducted by comparing the jaw movement between simulation data (virtual articulator) and real measurement data. As a result, the proposed virtual articulator achieves two important functions. Firstly, it replaces the traditional facebow transfer process by transferring the digital dental model to the virtual articulator through the anatomical relationship derived from the cranial CT data. Secondly, the jaw movement trajectory provided by optical tracking was incorporated into the mathematical articulation model to create a personalized virtual articulation with a small Fréchet distance of 1.7 mm. This virtual articulator provides a valuable tool that enables dentists to obtain diagnostic information about the temporomandibular joint (TMJ) and configure personalized settings of occlusal analysis for patients.

A Cephalometric Analysis Assessing the Validity of Camper’s Plane to Establishing the Occlusal Plane in Edentulous Patients

Complete denture fabrication requires multiple clinical and laboratory steps. One of the most critical clinical steps is establishing an anatomical occlusal plane based on hard and soft tissue references. The aim of this study was to determine whether age or gender affects the level of the Ala-Tragus plane to establish which reference point on the Tragus should be used when fabricating the occlusal plane in edentulous patients. Clinical photographs and lateral cephalometric radiographs with complete dentitions were taken from 58 volunteers at the DMD clinic at the University of Kentucky. Each photograph was superimposed over its corresponding cephalometric image. An analysis was conducted to establish the angle of the occlusal plane relative to the Ala-Tragus landmarks; this data was then grouped according to age and gender. The analysis shows that age and gender did not significantly affect where the Camper’s plane should be approximated for complete denture treatment. However, it was found that the most parallel line to the occlusal plane was Ala’s inferior border to the ‘Tragus’s inferior border. It should be noted that the volunteers’ skeletal classification was significantly related to a Cl III malocclusion tendency. Still, with this new information, functionality and esthetics can be more adequately addressed for patients undergoing complete denture treatment. Given our results, we suggest redefining the ‘Camper’s plane with a line extending from ‘Ala’s inferior border to the ‘Tragus’s inferior border instead of the superior border. Further consideration should be taken if the patient is a skeletal CL III malocclusion.

Aesthetic Preference in the Transverse Orientation of the Occlusal Plane in Rehabilitation: Perspective of Laypeople and Dentists

The present study had a convenience sample with 236 laypeople and 242 dentists who completed an online questionnaire to choose the most attractive image among six pairs for comparison. Control image: symmetric (parallelism between occlusal plane (OP), commissural line (CL), and interpupillary line (IL)). Change of Control, obtaining three images with a 3-degree inclination of the labial commissures. Image A: OP parallel to IL; Image B: OP parallel to CL; Image C: OP at 1.5 degree mean angulation between IL and CL. Non-parametric comparison (IBM© SPSS Statistics vs. 27.0, p < 0.05). The “Dentists” group’s decreasing order of preference (attractiveness) of the images is: Control > A > C > B (p < 0.05). In the “Lay” group, it is: Control > A > (C not ≠ B). Dentists significantly prefer more the Control and Image A than laypeople (p < 0.001). Sex (single exception in laypeople), age, and dentist’s area of activity did not interfere in the perception of attractiveness. Dentists and laypeople preferred the Control when compared to images with CL canted. In the existence of CL inclination, the preference of the groups was the IL as a reference for OP orientation, with the mean angulation or coincident with the CL being considered less aesthetic.

A singular oral appliance to treat obstructive sleep apnea in CPAP non-adherent patients

INTRODUCTION

The most prescribed treatment option for Obstructive Sleep Apnea (OSA) is CPAP; however, its adherence is limited. Oral Appliance therapy (OAT) is frequently an option or even an adjuvant, being the mandibular advancement Oral Appliance (OAm) the most used prescription. It modifies the upper airway, improving the airway patency. OAm construction is based on the occlusal plane to disocclusion. In this study, the DIORS® appliance was used, a singular OAm, based on Neuro-Occlusal Rehabilitation concepts, that uses Camper's plane as a disocclusion reference, in order to achieve neuromuscular balance and functional stability.

OBJECTIVE

This study primarily aimed to assess the DIORS® effectiveness in relation to clinical and polysomnographic outcomes. It was also evaluated if the use of DIORS® is as effective as titrated CPAP to treat CPAP non-adherent patients.

METHODS

Twenty patients were included in this study. Objective and subjective clinical data were assessed at a sleep laboratory using all-night polysomnography, and Epworth Sleepiness Scale (ESS), taken at three moments: Baseline, CPAP titration, and using DIORS®. Analysis of respiratory parameters as apnea/hypopnea index (AHI), oxyhemoglobin saturation levels, the arousal index and daytime sleepiness were taken as criteria for a successful OAT.

RESULTS

Respiratory and arousal parameters improved in both therapies, while DIORS® promoted a better ESS.

CONCLUSION

Results from the present work support that DIORS® is a viable and effective adjuvant therapy for patients with moderate to severe OSA non-adherent to CPAP.