Reference values and reliability of occlusal force distribution and occlusal time measured by the T-Scan system in adults with healthy dentition.

PURPOSE: Reference values of occlusal characteristics are needed to interpret the data obtained using the T-Scan System. This study aimed to establish reference values for and to assess the reliability of, occlusal force distribution in the maximal intercuspal position and the occlusion time in young adults with healthy dentition. MATERIALS AND METHODS: In total 178 adults with natural dentition participated in this retrospective cross-sectional study, of whom 76 performed a retest session. Several occlusal recordings were obtained from each participant using the T-Scan system while asking them to bite two or three consecutive times (multi-bite) or only once (single-bite) at the maximal intercuspal position. The lateral and anteroposterior occlusal force distribution were determined as percentages in the right and posterior teeth . Occlusion time was measured in seconds. After the occlusal force distribution and occlusion time percentiles were calculated, reliability was assessed by the intraclass correlation coefficient. RESULTS: The 5th-95th percentiles for occlusal force distribution were 34%-67% on the right teeth and 55%-94% on the posterior teeth. The 90th percentile for multi-bite occlusion time was 0.17 s and for single-bite occlusion time was 0.27 s. The intraclass correlation coefficients for lateral occlusal force distribution, anteroposterior occlusal force distribution, multi-bite occlusion time, and single-bite occlusion time were 0.70, 0.68, 0.58, and 0.67, respectively. CONCLUSIONS: This study generated reference values for key occlusal characteristics (occlusal force distribution and occlusion time) when using the T-Scan system. These values showed moderate reliability.

Side switch frequency while masticating different chewing materials, and its relationship with other masticatory behaviors and sensory perceptions.

OBJECTIVE: This cross-sectional study aimed to establish normative values for masticatory side switch (MSS) frequency in young Mexican adults and to assess the relationship between various indices and MSS frequency when masticating different chewing materials. DESIGN: We enrolled 101 dentate adults and performed four masticatory assays that involved masticating different chewing materials (i.e., two-colored chewing gum, sweet cracker, salty cracker, and bread). Participants were asked to eat and swallow these foods and to chew the gum for 40 cycles and the following indices were determined: MSS index (MSSI), unilateral chewing index, chewing cycle duration, and number of cycles before terminal swallowing. The participants then rated perceived flavor intensity, salivary flow, and muscle fatigue during each trial. RESULTS: The MSSI ranged from 0.03-0.06 (10th percentile) to 0.48-0.54 (90th percentile). A repeated-measures general linear model revealed a mean MSSI value of 0.28 (95 %CI, 0.25-0.30) adjusted by several factors. Male sex, soft food, and the last chewing period were associated with lower MSS frequency. Spearman's test showed a high correlation for the MSSI among the different foods. MSSI correlated negatively with the unilateral chewing index for each chewing material and with number of cycles for the sweet cracker. However, no significant correlation was detected between MSSI and sensory perception. CONCLUSIONS: In healthy dentate individuals, the mean MSS relative frequency is 25-30 % with an 80-central percentile of 5-50 % of the maximum possible side changes. Lower MSS frequencies were detected in men, when chewing soft food, and during the final chewing period.

Accuracy of digital and conventional systems in locating occlusal contacts: A clinical study.

STATEMENT OF PROBLEM: The accuracy of methods used for locating occlusal contacts throughout the entire clinical procedure has been poorly studied. PURPOSE: The purpose of this clinical study was to determine the reproducibility and criterion validity for different methods of locating occlusal contacts. MATERIAL AND METHODS: Thirty-two adults with natural dentitions participated in this cross-sectional test-retest study. In total, occlusal contacts at maximum intercuspation were recorded by using 15 methods: silicone transillumination with Occlufast Rock (40, 50, 100, and 200 µm) and Occlufast CAD (40 and 50 µm); virtual occlusion (100, 200, 300, and 400 µm); articulating film (12-, 40-, 100-, and 200-µm-thick); and T-Scan III. Images of the occlusal records were scaled and calibrated spatially, and the occlusal contacts of the right posterior mandibular teeth were delimited by using the FIJI software program. Reproducibility was expressed as 95% confidence intervals (95% CI) of the percentage of agreement in the location of the occlusal contacts between images from the test sessions against retest sessions using the same method. Criterion validity was expressed as 95% CI of the percentage of agreement in the location of the occlusal contacts between images from the test sessions against images from Occlufast Rock (criterion standard). RESULTS: Occlufast Rock achieved 85% to 95% agreement in the location of the occlusal contacts between the 2 sessions, whereas Occlufast CAD, 200-µm articulating film, and T-Scan offered 79% to 86%, 68% to 75%, and 65% to 75% agreement, respectively. The most valid method was Occlufast CAD (74% to 80%) followed by the 200-µm articulating film (57% to 63%), 400-µm virtual occlusion (53% to 62%), 100-µm articulating film (52% to 60%), and T-Scan (48% to 56%). CONCLUSIONS: Conventional methods, such as 100- and 200-µm articulating film and digital methods, including 400 µm virtual occlusion and T-Scan, offer sufficient accuracy in locating the occlusal contacts. However, strategies are needed to improve accuracy.

Influence of masticatory side switch frequency on masticatory mixing ability and sensory perception in adults with healthy dentitions: A randomized crossover trial.

STATEMENT OF PROBLEM: The advantages and disadvantages of frequently changing sides while masticating remain unclear. PURPOSE: The purpose of this clinical study was to determine the effect of varying the frequency of masticatory side switches on masticatory mixing ability and sensory perception in dentate adults. MATERIAL AND METHODS: This nonblinded, randomized 12-period crossover study, conducted at Barcelona Dental School from January to March 2022, included 36 healthy adults with natural dentitions (median age, 23.5 years; 26 women). Participants were randomly allocated to 12 sequences and performed 12 masticatory assays masticating a 2-colored gum for 40 cycles each using the following masticatory styles as interventions: freestyle, unilateral right, unilateral left, and switching sides 5%, 15%, and 25%. The primary outcome was the mixing ability index (MAI), defined as the standard deviation of the red channel intensity of the masticated gum in the color-histogram plugin of the ImageJ software program. Participants also rated the perceived flavor intensity and salivary flow on a visual analog scale. Data were analyzed by repeated measures analysis of variance (α=.05). RESULTS: The MAI was similar for all masticatory styles (P=.63). Participants perceived greater flavor intensity (mean difference: 8%, 95% CI: 1% to 15%) and salivary flow (mean difference: 11%, 95% CI: 0% to 21%) with 25% side switching compared with freestyle or unilateral mastication. CONCLUSIONS: Frequently switching the masticatory side while masticating gum does not alter the mixing ability, but it appears to enhance salivary flow and flavor intensity.

Effect of side switch frequency on masticatory performance and rhythm in adults with natural dentition: A randomised crossover trial.

BACKGROUND: The relationships between the frequency of masticatory side switches (MSS) and other aspects of masticatory function are not clear. OBJECTIVES: In this study, we determined the effect of MSS frequency on masticatory performance and rhythm in dentate adults and explored the between-subject relationships among side switch frequency, masticatory rhythm and laterality. METHODS: In this crossover study, subjects performed six masticatory patterns of five trials each, chewing bagged silicone for 20 cycles. The six patterns were freestyle, unilateral right, unilateral left, and switching sides one, three and five times. Masticatory performance and rhythm were determined for each style by median particle size (MPS) and chewing cycle duration, respectively. In the freestyle mastication pattern, masticatory laterality was assessed by the unilateral chewing index, and the frequency of MSS was assessed by the MSS Index. Data were analysed using Friedman's test and repeated measures analysis of variance. RESULTS: We included 29 participants (15 women; median age, 23 years). No significant between-subjects differences in the MPS were detected obtained by switching one, three or five times per trial. Chewing cycle duration increased with the MSS number per trial. During freestyle mastication, the MSS Index was inversely correlated with the unilateral chewing index (Rho -0.569; 95% CI -0.25 to -0.78; p = .001; Spearman test), but not with the MPS or chewing cycle duration. CONCLUSION: Differences in MSS frequency do not affect masticatory performance, but they do alter the masticatory rhythm. Individuals with a higher MSS frequency also have a more symmetrical chewing pattern.

Nutritional status and masticatory function of the indigenous compared with non-indigenous people of Nayarit, Mexico.

OBJECTIVE: The objective of this study was to compare the nutritional statuses and masticatory function of the non-indigenous and indigenous adult people of the state of Nayarit, Mexico. DESIGN: Forty-two indigenous (Cora or Huichol ethnic group) and 100 non-indigenous people, all adults with natural dentition, participated in this cross-sectional study. They performed a free-style masticatory test consisting five trials of chewing silicon pieces for 20 cycles. Masticatory performance was determined by sieving the silicon particles, masticatory laterality was determined by calculating the asymmetry index, and the cycle duration was also recorded. Weight and body fat mass were measured using a portable digital weighing machine and height and body circumferences were recorded to calculate the body mass index (BMI), body fat percentage, and the waist-hip ratio. Each aspect of masticatory function and each nutritional variable were compared using T-test, analysis of variance, and Kruskal-Wallis or Mann-Whitney tests, as appropriate. RESULTS: Body fat percentage, BMI, and waist-hip ratio were higher (P < 0.0005) in the indigenous group compared to the non-indigenous. The indigenous group had a significantly shorter stature than the non-indigenous group. Cora group had a higher BMI and higher percentage of body fat than the Huichol group (P < 0.05). No significant differences were detected between the groups for any aspect of masticatory function. CONCLUSIONS: Indigenous people from the Nayarit, especially the Cora ethnic group, are more obese, have more total body fat, and more abdominal fat than non-indigenous people. Indigenous people show similar masticatory function.

Effect of a Mandibular Advancement Device on the Upper Airway in a Patient With Obstructive Sleep Apnea.

The authors present a case of a 33-year-old male patient with obstructive sleep apnea syndrome who was treated with a mandibular advancement device with excellent results. The aim of this study is to underline the importance of new instruments that allow evaluating the upper airway with greater precision, such as cone beam tomography. Given the diagnosis and treatment, the upper airway was assessed using cone beam tomography; an increase in UA volume of 22% was observed (initial volume 22,962 mm), along with a 28% increase in area (initial area 971 mm). The evaluation of the UA using teleradiography also showed an increase in the points evaluated, with the midpoint of the soft palate presenting the greatest increase.

Case Report: Interdisciplinary management of a complex odontoma with a periapical involvement of superior anterior teeth.

This case report aims to describe the management of a complex odontoma with endodontic involvement of surrounding teeth utilizing a new bioceramic cement consisting of five mineral oxides (5MO) as a retro-filling material. The patient presented for routine consultation with slight dental mobility in the antero-superior region. Upon clinical and computed tomography examination, bone rarefaction was observed in the apical region of teeth 11 and 12, external root resorption in the involved teeth and necrotic pulp of tooth 12. Root canal treatment was performed in teeth 11 and 12. Later, local surgical excision of the lesion was carried out, finding a mass with clinical features of complex odontoma, with histopathological examination of the mass confirming this diagnosis. Retro-filling of tooth 12 with 5MO was carried out. No signs and symptoms were observed over twelve-months of follow-up, with bone neoformation observed in the region. Therefore, 5MO appears to be an effective bioceramic cement that has reparative features.

Lack of relationship between masticatory performance and nutritional status in adults with natural dentition.

OBJECTIVE: This study assessed the relation among several aspects of the masticatory function and the nutritional status in adults with natural dentition. DESIGN: One hundred adults with natural dentition participated in this cross-sectional study. They performed one free-style masticatory test consisting of five trials of 20 silicon-chewing cycles. The preferred chewing side was determined by calculating the asymmetry index. Masticatory performance was determined by sieving the silicon particles, and the cycle duration was also recorded. Weight, body water percentage, body fat mass, muscle mass and osseous mass were measured using a portable digital weighing machine. Body mass index (BMI), waist-hip ratio, skinfold thickness and the upper-arm composition were determined. The relation between masticatory function and a nutritional variable were tested using Pearson or Spearman rank correlation coefficients or using analysis of variance or the Kruskal-Wallis H-test and the Mann-Whitney U test, as appropriate. RESULTS: Whereas body fat percentages for women were significantly higher than for men, the body mass index was higher in men than in women. Participants who were underweight chewed more asymmetrically and more slowly than normal weight or obese participants. A negative correlation was observed between body fat percentage and masticatory laterality. No relation between masticatory performance and any nutritional status indicator was detected. CONCLUSION: Being underweight and having a low body fat percentage seem to be related to a masticatory lateral asymmetry and to a large cycle duration in young adults with natural dentition. Masticatory performance does not seem to be related to nutritional status.

Reliability of a visual analog scale for determining the preferred mastication side.

STATEMENT OF PROBLEM: Although the visual analog scale (VAS) is a simple tool for quantitatively measuring symptom perception, no studies have used the VAS to assess the degree of subjective masticatory laterality. PURPOSE: The purpose of this study was to assess the reliability of the VAS for determining the preferred mastication side (PMS) and to compare it with other methods. MATERIAL AND METHODS: A cross-sectional study was conducted in which 42 adults with natural dentition performed 2 masticatory sessions. Eight different methods were used to determine the PMS by combining different definitions, food tests, measurements, and number of cycles assessed. A test-retest was performed in 10 participants to evaluate the reliability of each method using the intraclass correlation coefficient. To assess the validity of the different methods, the Pearson correlations were performed (α=.05) between the 8 methods. RESULTS: Self-assessment using the VAS had the highest reliability; it also had a positive and significant relationship with 6 of the 7 other methods. The method that showed the best validity used bagged silicone as the test food, determined the PMS by video recording, and assessed all masticatory cycles using the asymmetry index. Low reliability was found for methods using the location of gum bolus at standardized time intervals or electromyographic recordings. CONCLUSIONS: The VAS provided a highly reliable means of assessing the degree of masticatory laterality perceived by the participant, with a positive and significant correlation with the majority of the other methods.

Relationship between jaw movement and masticatory performance in adults with natural dentition.

OBJECTIVE: This study determines the relationship between several characteristics of jaw movement and masticatory performance determined by multiple regression analysis and adjusted for occlusal contact area and bite force. MATERIALS AND METHODS: Forty-two young adults with natural dentition participated in this cross-sectional study. Occlusal contact area was determined at the maximum intercuspal position by scanning interocclusal records. Maximum unilateral force was measured by means of a gnathodynamometer. The height and amplitude of mastication, occlusal glide length, lateral guidance angle, anterior-posterior distance and cycle duration were recorded using the ARCUSdigma II system. Masticatory performance was determined by sieving the Optosil particles resulting from 20 chewing cycles. RESULTS: Median particle size was negatively associated with height of mastication, maximum bite force, occlusal contact area and amplitude of mastication. Stepwise multiple linear regression analysis revealed that the height of mastication and dental guidance angle are the characteristics of jaw movement most closely related to masticatory performance. CONCLUSIONS: In adults with natural dentition, a large vertical height of mastication and a small dental guidance angle are the characteristics of jaw movement most closely associated with good masticatory performance, determined by multiple regression analysis and adjusted for occlusal contact area and bite force.

Is the side with the best masticatory performance selected for chewing?

OBJECTIVE: This study assessed the degree of relationship between masticatory laterality and lateral asymmetry of masticatory performance using silicon pieces enclosed in a latex bag. DESIGN: Forty-two young adults with natural dentition participated in this cross-sectional, observational study. They performed four different masticatory assays, each consisting of five trials of chewing three pieces of silicon for 20 cycles. In one assay, they were asked to masticate unbagged silicon free-style, whilst in the three other assays they were asked to masticate bagged silicon free-style, unilaterally on the right-hand side and unilaterally on the left-hand side. The preferred chewing side was determined by calculating the asymmetry index for both the free-style assays. Masticatory performance was determined by sieving the silicon particles and the cycle duration was also recorded. Data were analysed using independent samples or paired t-test and linear regression. RESULTS: Masticatory function using the bagged silicon was similar to that using the unbagged silicon. A significant and positive relationship was observed between the preferred chewing side expressed as the asymmetry index and the side with better masticatory performance. Alternate unilateral chewers demonstrated better masticatory performance than unilateral chewers. However, when free-style and unilateral chewing were compared for each subject, unilateral chewing was found to be as efficient as - or even more efficient than - free-style chewing. CONCLUSIONS: There is a positive association between the preferred chewing side and the more efficient side. Alternate unilateral mastication per se does not promote better masticatory performance than consistently unilateral mastication.