Clinical analysis of CAD-CAM milled and printed complete dentures using computerized occlusal force analyser

BACKGROUND: Digital complete dentures (CDs) by computer-aided designing and computer-aided manufacturing (CAD-CAM) techniques (milling and three-dimensional (3-D) printing) have been evaluated clinically and provided satisfactory results. But clinical studies assessing occlusal forces by digital dentures are lacking. OBJECTIVES: To compare the occlusal force parameters in complete dentures (CDs) fabricated by milling, 3-D printing and conventional techniques having 3 commonly used occlusal schemes, using computerized occlusal force analysis system (Tech-Scan III- T-Scan III). METHODS: A total of 45 CDs were fabricated for 5 patients. Nine sets of CDs were made for each patient and were divided into 3 groups: Conventional CDs (CCD), Milled CDs (MCD), and 3-D printed CDs (3-DP CD). The CDs in each group were further divided into 3 sub-groups based on occlusion schemes – bilateral balanced (BBO), lingualized (LO) and mono plane (MP). Occlusal force analysis [percentage (%) of occlusal force applied on the right and left sides of the arch difference between them, centralization of forces and % of maximum occlusal/bite force] was done using computerized occlusal analysis system (T-Scan III) at the time of denture insertion. Univariate regression analysis and logistic regression analysis were performed (p< 0.05). RESULTS: The intergroup comparison of force distribution on right and left side in CDs fabricated by various techniques showed insignificant differences (p> 0.05) but statistically significant differences (p< 0.01) were found in Right – Left side force difference, maximum bite force % and centralization of forces. The maximum force difference on right and left side was observed CCD with MO (37.48 ± 1.03 N) and maximum occlusal-bite force % was observed for 3-DPCD with LO (95.40 ± 1.30 N). In comparison to 3-DP CD, the chances of centre of force out of ellipse (centralization of forces) was 3.36 and 2.15 times more in CCD and MCD techniques made CDs respectively. CONCLUSIONS: The occlusal parameters in CDs were affected by the fabrication techniques and occlusal schemes of CDs. The digital CDs retain adjusted occlusal schemes better and 3-DP CDs with BBO and LO occlusal schemes provided centralization of forces, better distribution and high maximum occlusal force % respectively.

Measurement of the Maximum Occlusal Bite Force and its Relation to the Caries Spectrum of First Permanent Molars in Early Permanent Dentition

Objective: To determine the maximum occlusal bite force (MOBF) of the complete spectrum of dental caries in first permanent molars (FPMs) in children aged 7–9 years. Study design: A cross-sectional study was conducted on 123 children. The evaluation of the caries spectrum of FPMs was carried out using the Caries Assessment Spectrum and Treatment index (CAST). The MOBF was measured in the FPM region using the portable occlusal force gauze. Independent sample t-test and one-way analysis of variance test were performed to compare MOBF with CAST scores of FPMs. Based on the CAST scores, FPMs were categorized into three groups, group 1: healthy (score 0, 1, 2), group 2: premorbid (score 3), group 3: morbid (score 4, 5). Results: A significantly lower MOBF was observed (167.56 N ± 49.77) in the morbid stage (group 3) than in the premorbid stage (group 2: 291.57 N ± 56.64), and healthy (group 1; 320.93 N ± 54.23). Intergroup comparison also revealed that FPMs in the healthy stage was associated with a higher bite force compared to those in the premorbid and morbid stages (p&lt;0.001). Conclusions: The mean MOBF decreased with the progression of the caries spectrum of FPMs in early permanent dentition.

Maximum Voluntary Bite Force Generated by Individuals with Healthy Dentition and Normal Occlusion

OBJECTIVE: Masticatory muscles work coordinately along with bones and teeth in these jaws to generate occlusal bite force. The amount of force varies from person to person. This study was performed to measure the amount of bite force to associated with demographics like age and gender so that we may compare it with prosthodontically rehabilitated dentition which may help us in the treatment plan. METHODOLOGY: Bite force was recorded with an Occlusal Bite force meter (GM-10 Nagano Keiki Japan). A sample of 204 Pakistani individuals who are aged between 13 to 40 years and divided into three age groups: I (13-20years), II (21-30 years), III (31-40 years) is recorded. A mean of three left sided and a mean of three right sided maximum voluntary bite forces were calculated and a final mean of the two were taken to find out the Mean Maximum Voluntary Bite force. RESULTS: Mean Maximum Voluntary Bite Force was calculated as 533.42 N ± 185.44 N, whereas Males have Mean MVBF 635.23 N ± 179.86 N and Females have Mean MVBF 431.61 N ± 125.82 N. Mean Maximum Voluntary Bite force with respect to age; group I is 476.11 N ± 181.27 N, group II is 550.93 N ± 191.83 N. MVBF of group 3 is 573.21 N ± 171.18 N. CONCLUSION: Mean MVBF with standard deviation was calculated as 533.42 N ± 185.44 N, with males having bite force significantly higher than the females. In all the groups, gender was significantly associated with MVBF. The bite force is also positively correlated with age. KEYWORDS: Bite force, Human Bite force, bite force gauge, maximum bite force HOW TO CITE: Nawaz MS, Yazdanie N, Hussain S, Moazzam M, Haseeb M, Hassan M. Maximum voluntary bite force generated by individuals with healthy dentition and normal occlusion. J Pak Dent Assoc 2020;29(4):199-204.