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.

Diagnostic accuracy of clinical signs to detect erosive tooth wear in its early phase.

BACKGROUND: Agreement exists about most of the clinical features of erosive tooth wear, though no evidence supports their validity in diagnosing the condition. OBJECTIVE: This study aimed to determine the accuracy of clinical signs for diagnosing erosive tooth wear in a young adult general population. METHODS: We conducted a cross-sectional study of dental students. In the first session, two examiners independently determined the presence of erosive tooth wear based on glazed enamel surfaces, morphological changes on non-occlusal surfaces, flattening of convex areas, or any type of concavity. In the second session, one examiner recorded the presence of clinical signs according to the Tooth Wear Evaluation System. The diagnostic accuracy of each clinical sign, both alone and combined, was assessed by calculating their sensitivity and specificity for detecting erosive tooth wear and performing multivariate logistic regression models. RESULTS: Of the 147 participants (78 women and 69 men; median age, 22 years) we included, 76.2% had erosive tooth wear. The single clinical signs with greatest balance between the sensitivity and specificity were 'convex areas flatten' (63% and 71%, respectively) and 'dull surface' (47% and 89%, respectively). Multivariate logistic regression revealed that 'preservation of the enamel cuff' (odds ratio, 22) and the combination of 'smooth silky shining, silky glazed appearance, and dull surface' (odds ratio, 68) had the best predictive values. CONCLUSIONS: The most accurate clinical signs for detecting early erosive tooth wear were dull surface, flattened convex areas and preservation of the enamel cuff.

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.

Characterization of Mandibular Border Movements and Mastication in Each Skeletal Class Using 3D Electromagnetic Articulography: A Preliminary Study.

Mandibular movement recording is relevant for the planning and evaluation of mandibular function. These movements can include mandibular border movements (MBM) or mastication. Our objective was to characterize the kinematics of MBM and mastication among skeletal classes I, II, and III in the three spatial planes. A descriptive cross-sectional study was conducted with 30 participants. Instructions were provided on how to form Posselt's envelope and to perform masticatory. After data processing, we obtained numerical values for the areas, trajectories, and ranges of MBM that formed Posselt's envelope and the values for speed, masticatory frequency, and the areas of each masticatory cycle. Significant differences were found in the area of Posselt's envelope in the horizontal plane between skeletal classes I and III and in the range of right laterality between skeletal classes II and III. Mastication showed significant differences in the area of the masticatory cycles in the horizontal plane between classes I and III and between classes II and III. In conclusion, there were differences in MBM and mastication between skeletal classes III and I in the horizontal plane. This study supports the need to establish normal values for mandibular kinematics in skeletal class III.

Satisfaction with labial reinforcement of custom-made mouthguards among a cohort of rugby union players: A randomized crossover trial.

PURPOSE: The optimal mouthguard design for athletes remains unclear. This study assessed satisfaction and preference among rugby union players for custom mouthguards with and without labial reinforcement. It also assessed discomfort and perceived protection. MATERIALS AND METHODS: This prospective randomized controlled trial used a crossover design of four 1-week periods to compare conventional (Type A) and labial reinforced (Type B) customized 2 mouthguards for rugby union players from February to May 2022. Type B mouthguards included a 0.75-mm insert of polyethylene terephthalate glycol (Duran) in the anterior labial region. We ensured intraoral occlusion accommodation for both mouthguards. Players wore each mouthguard type when training and in competitive matches for 2 weeks according to one of two randomized sequences, and after each session, they rated the mouthguard on 10-point scales regarding discomfort, functional interference, protection, and general satisfaction. After 4 weeks, we asked participants to nominate their preferred mouthguard. RESULTS: In total, 22 of the 24 invited players (16 men and 6 women) were included. We observed no significant differences in discomfort, functional interference, protection, or general satisfaction by mouthguard type (P > .05 Wilcoxon test). Ultimately, 12 players (55%) preferred the Type A mouthguard and 10 (45%) preferred the Type B mouthguard (P = .832; one-sample binomial test). No serious adverse events occurred. CONCLUSIONS: Labial reinforcement does not affect satisfaction, perceived comfort and protection, or mouthguard preference among rugby union players. Int J Prosthodont 2023. doi: 10.11607/ijp.8444 Trial registration: NCT05238480 (ClinicalTrials.gov).

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.

Sex-specific reference values for the crown heights of permanent anterior teeth and canines for assessing tooth wear.

OBJECTIVE: We propose sex-specific reference values for the clinical crown height of anterior teeth and canines. MATERIAL AND METHODS: In this cross-sectional study, 1426 teeth were analysed from 169 undergraduate and postgraduate dental students (83 women and 86 men, median age 22 years). Teeth with worn or totally restored incisal edges, or gingival inflammation were excluded. Age, gender and body height were recorded and the degree of tooth wear was scored according to the quantification module of the Tooth Wear Evaluation System. The clinical crown heights of all anterior teeth and canines were measured from the gingival margin to the incisal edge with a digital calliper. Reference values for tooth groups were obtained at the percentiles 10, and expressed by sex if there was a significant difference between men and women. RESULTS: Mean crown heights were bigger in men than in women for each tooth group (p = .028). Clinical crown heights showed sexual dimorphism at the 10th percentiles for all tooth groups except for mandibular anterior teeth. CONCLUSIONS: For assessing tooth wear, the sex-specific reference values for the clinical crown height of young adults Caucasoids range from 7.5 mm to 9.0 mm in women and from 7.5 mm to 9.5 in men.

Prevalence of dental attrition and its relationship with dental erosion and salivary function in young adults.

OBJECTIVES: The aim of this study was to estimate the prevalence of dental attrition in a young adult population and to explore associated factors. METHOD AND MATERIALS: Dental students aged 18 to 40 years old with a minimum of 24 natural teeth were invited to take part in this cross-sectional study. Their demographic information, medical history, perceived stress, frequency of dietary acid intake, and frequency of oral habits were obtained through several questionnaires. Assessment of each type of tooth wear (erosion, attrition, and abrasion) was performed according to the tooth wear evaluation system (TWES 1.0). All participants underwent salivary tests. Statistical analysis was performed by chi-squared or Mann-Whitney tests and logistic regression models. RESULTS: In total, 178 participants (88 women and 90 men) with a median age of 22 years were included and of those 74.7% (95% confidence interval [CI], 68% to 81%) had dental attrition. Univariate analysis revealed positive associations for male sex, age, body mass index, awake bruxism frequency, and erosive tooth wear with the presence of dental attrition. Multivariable logistic regression (Nagelkerke r2 = 0.31) indicated that dental attrition was associated with erosive tooth wear (adjusted odds ratio [aOR], 6.3; 95% CI, 2.8 to 14.2), body mass index (aOR, 1.3; 95% CI, 1.1-1.5), and age (aOR, 1.2; 95% CI 1.0 to 1.3). CONCLUSION: Dental attrition is present in most young adults of Catalonia. The associated factors were erosive tooth wear, body mass index, and age. Slight alterations of salivary parameters do not seem to predict dental attrition. (Quintessence Int 2023;54:168-175; doi: 10.3290/j.qi.b3622405).

Effect of chewing behavior modification on food intake, appetite and satiety-related hormones: A Systematic Review

Purpose: Obesity has become a growing public health issue worldwide. Studies have shown that eating rate is one of the most important factors to consider in the strategies to prevent and/or treat obesity. Eating rate can be reduced through different strategies, such as an increase in oro-sensory exposure, the modification of food texture, and an increase in the number of chewing cycles. The aim of this systematic review was to analyze the available evidence regarding the effect of chewing behavior modification on the parameters that contribute to obesity. Methods: A systematic search was done on the electronic databases Pubmed, Cochrane Central Register of Controlled Trials, and Scopus, using the terms "mastication", "chewing", "chewing speed", "prolonged chewing", "number of chews", "masticatory cycles" "satiety" "satiety response" "appetite", "appetite regulation", "nutritional status" and "obesity". Results: A total of 23 intervention studies were selected that intervened in the participants' chewing behavior, either by reducing the eating rate, increasing oro-sensory exposure, food hardness or the number of chewing cycles. In most studies these interventions were effective at reducing food intake, subjective appetite and improving the plasma levels of satiety-related hormones and metabolites; moreover, they reduced body mass index in the long term. Conclusion: The currently available evidence seems to indicate that modifications to chewing behavior can bring with it a myriad of benefits for the treatment of obesity.

Propósito: La obesidad se ha convertido en un problema de salud pública creciente a nivel mundial. Investigaciones han demostrado que la tasa de ingesta es uno de los factores importantes a considerar en las estrategias para prevenir o tratar la obesidad. La tasa de ingesta puede reducirse a través de diferentes estrategias; el aumento de la exposición oro-sensorial, la modificación de la textura de los alimentos y el aumento en el número de ciclos masticatorios. El objetivo de esta revisión sistemática fue analizar la evidencia disponible sobre el efecto de la modificación de la conducta masticatoria sobre los parámetros que contribuyen a la obesidad. Métodos: Se realizó una búsqueda sistemática en las bases de datos electrónicas Pubmed, Cochrane Central Register of Controlled Trials y Scopus, con los términos "mastication", "chewing", "chewing speed", "prolonged chewing", "number of chews", "masticatory cycles" "satiety" "satiety response" "appetite", "appetite regulation", "nutritional status" y "obesity". Resultados: Se seleccionaron 23 estudios que intervenían en el comportamiento masticatorio de los participantes, ya sea reduciendo de la tasa de ingesta, aumentando la exposición oro-sensorial, dureza de los alimentos y número de ciclos masticatorios. Estas intervenciones resultaron ser efectivas para reducir la ingesta de alimentos, el apetito subjetivo y mejorar los niveles plasmáticos de las hormonas y metabolitos relacionados con la saciedad, además, a largo plazo, permitieron reducciones en el índice de masa corporal. Conclusión: La evidencia disponible actualmente parece señalar que las modificaciones en el comportamiento masticatorio pueden traer consigo múltiples beneficios para el tratamiento de la obesidad.

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.

Variation in Dental Occlusal Schemes Two Years After Placement of Single-Implant Posterior Crowns: A Preliminary Study.

Some authors have recommended that implant-supported single crowns should only contact during heavy clenching. However, a lack of occlusal contact with moderate clenching may cause supraeruption of antagonist natural teeth. The main objective of this study was to assess changes in the occlusal contacts of posterior implant-supported single crowns with natural antagonist teeth 2 years after placement. The occlusal schemes of 14 patients who received 16 implant-supported single crowns in molar and premolar regions were assessed in this prospective study. Just after crown placement, at 6 months and after 2 years, a silicone maxillomandibular relationship and T-scan records were obtained during the intercuspal position with light and heavy clenching, determined using near half of the maximum force and maximum force, respectively. Occlusal contacts were assessed quantitatively and qualitatively in the implant-supported single crowns, contralateral tooth, and adjacent tooth; the latter 2 were used as controls. After 6 months and 2 years, no significant variations were observed in any region of the occlusal scheme in any assessments, including silicone record or T-Scan, using light or heavy clenching, and qualitative or quantitative occlusal contact assessment. In this preliminary study, the occlusal scheme did not vary at the intercuspal position 2 years after placing posterior implant-supported single crowns.

Attitudes and opinions towards the prevention of orofacial injuries among water polo coaches in Catalonia: A cross-sectional study.

BACKGROUND/AIM: Although orofacial injuries are frequent in water polo, fewer than 10% of players use mouthguards. The aim of this study was to determine the degree to which coaches and sports club managers encourage mouthguard use in water polo and to explore their opinions regarding other strategies designed to reduce the prevalence of orofacial injuries. MATERIAL AND METHODS: This was a cross-sectional study in which the coaches and sports club managers of 16 water polo clubs in Catalonia were invited to participate. An online questionnaire was administered to the coaches to obtain general data, to determine whether they had recommended mouthguard use to their players and to record their opinions on other strategies designed to reduce the prevalence of orofacial injuries. Sports club managers were interviewed about the facilities offered by their clubs for players to obtain mouthguards and about their attitudes regarding the prevention of orofacial injuries. RESULTS: The questionnaire was administered to 72 coaches who trained 111 teams during the 2019-2020 season, together with 14 sports club managers. Coaches of only 11 teams (10%) recommended mouthguard use to their players. Two clubs (14%) offered some facilities to their players to obtain mouthguards. Interestingly, only 18% of the coaches believed that mouthguard use should be mandatory, in contrast to 50% of the sports club managers (p = 0.017; Fisher's exact test). Most coaches and sports club managers believe that a video monitoring system should be used to identify dangerous play and that orofacial injuries should be reported under a surveillance programme. CONCLUSIONS: Few water polo coaches recommend mouthguard use to their players and very few clubs offer facilities to obtain custom-made oral protection. However, most coaches and sports club managers agree that the rules should be modified to protect players from aggressive play.

Masticatory rhythm 3 months after treatment with unilateral implant-supported fixed partial prosthesis: A clinical study.

STATEMENT OF PROBLEM: Whether treatment with an implant-supported fixed partial prosthesis (ISFPP) affects the masticatory rhythm in patients with unilateral posterior missing teeth is unclear. PURPOSE: The purpose of this prospective clinical study was to determine the change in masticatory rhythm in participants with unilateral posterior missing teeth 3 months after treatment with an ISFPP and to assess whether treatment influenced the stability of the masticatory rhythm. MATERIAL AND METHODS: Thirty participants (mean age 59 years; 17 women) with unilateral posterior missing teeth were treated with 1-, 2-, or 3-unit ISFPPs. Ten healthy individuals (mean age 36 years; 8 women) with a complete natural dentition were included in a control group. In this prospective study, each participant performed 3 masticatory assays (freestyle, unilateral right, and unilateral left) at baseline and at the 3-month follow-up. Each assay comprised 5 trials of 20 cycles masticating pieces of silicone placed in a latex bag. The time needed to complete the 20 masticatory cycles per trial was measured, and the mean masticatory frequency was calculated for each assay. Coefficients of variation were then calculated from the 5 mean values of the masticatory trials. Differences in the data at 3 months and baseline were analyzed by using the Wilcoxon or paired t tests. The control and treated groups were compared by analysis of variance or Mann-Whitney U tests (α=.05). RESULTS: After 3 months, participants treated with ISFPPs showed an increase of 8.7% in masticatory frequency during freestyle mastication (P<.001) and an 8.0% increase during unilateral mastication on the treated side (P<.01). At baseline, the coefficient of variation of masticatory frequency on the treated side was higher in the ISFPP group than in the control group during unilateral mastication (P=.033). Three months after treatment, there was a significant reduction in the coefficient of variation during unilateral mastication on the treated side of the ISFPP group (P<.001). The treatment group also reached a masticatory frequency similar to that of the control group (75 and 78 cycles per minute, respectively). CONCLUSIONS: Treatment with ISFPPs accelerated the masticatory rhythm of individuals with unilateral posterior missing teeth, who achieve similar rhythms to those with complete natural dentitions. The stability of the masticatory rhythm was also restored, indicating an improvement in masticatory function.

Relationship between Unilateral Posterior Crossbite and Human Static Body Posture.

BACKGROUND: We compared photogrammetry-assessed body posture between young adults with and without unilateral posterior crossbite (UPCB). Assessments were controlled by vision, mandibular position and sitting/standing position. In addition, we aimed to determine the relationship between UPCB laterality and the direction of body posture using photogrammetry and a static postural platform. METHODS: Adults with natural dentition, with and without UPCB, were enrolled. Static body posture was assessed by photogrammetry based on horizontal acromial alignment and horizontal anterior-superior iliac spine (ASIS) alignment. Frontal photographs were taken with participants asked to open or close their eyes and hold their jaws at rest, at an intercuspal position, and at left or right lateral positions. Distribution of foot pressure was recorded using a static postural platform at different visual input and mandibular positions. General linear models with repeated measures were used to assess the effect of the various within- and between-subject factors. RESULTS: In total, 36 adults (left UPCB = 12; Right UPCB = 6; controls = 18) participated. There were significant differences between the control and UPCB groups in horizontal alignment at the acromion (p = 0.035) and ASIS (p = 0.026) levels when controlled by visual input and mandibular position. No significant differences in horizontal alignment or foot pressure distribution were observed by laterality in the UPCB group. CONCLUSION: The presence of UPCB affects static body posture, but the side of crossbite is not related to the direction of effect on static body posture.

Effect of thickness and occlusal accommodation on the degree of satisfaction with mouthguard use among water polo players: A randomized crossover trial.

BACKGROUND/AIM: The optimal mouthguard type and design for each player and sport are currently unknown. The aim of this study was to assess the effect of using a thicker custom-made mouthguard with occlusal accommodation on the degree of satisfaction among water polo players. MATERIAL AND METHODS: Twenty-five elite water polo players participated in this randomized four-period crossover trial conducted from February to May 2019. For each participant, two customized mouthguards were fabricated using 4-mm ethyl vinyl acetate foil: Type A included no occlusal accommodation, and Type B included a 2-mm occlusal accommodation. Players wore each mouthguard during training sessions and competitions for 2 weeks in one of two randomized sequences. After each match or training session, players were asked to evaluate the mouthguards on 10-point scales across three domains: discomfort or interference with function, protection, and general satisfaction. Mouthguard preference was also recorded. RESULTS: The mouthguard with occlusal accommodation was reported to interfere more with speech and swallowing (P < .001) and with esthetics, breathing, and athletic performance (P < .05) compared with the conventional mouthguard. Although occlusal accommodation was associated with a higher perceived degree of protection (mean difference 0.5; 95% CI: 0.2-0.8), players were still more satisfied with the conventional mouthguard (mean difference 1.5; 95% CI: 0.8-2.3). Two players preferred the occlusal mouthguard, whereas 22 preferred the conventional mouthguard (P = .007). CONCLUSIONS: Among water polo players, occlusal accommodation increasing the thickness of the custom-made mouthguards may offer a greater perceived sense of protection, but this comes at the cost of greater discomfort and reduced overall satisfaction. Dentists can recommend conventional mouthguards for most water polo players.

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.

Reliability and Validity of T-scan and 3D Intraoral Scanning for Measuring the Occlusal Contact Area.

PURPOSE: To determine the reliability of T-scan and 3D intraoral scan techniques for assessing the occlusal contact area (OCA), compared to occlusal registration and also to assess the validity of the techniques. MATERIALS AND METHODS: Thirty-one dentate adults participated in this cross-sectional study. T-scan records were used to measure the OCA at maximum bite force and at 50% of maximum force using the software's bite force selection tool. A second method measured the OCA between 2 virtual models scanned intraorally using a 3D surface scan and considering the occlusal contact at 2 interocclusal distances (0-100 and 0-200 µm). The third method measured OCA using occlusal registration at moderate and maximum occlusal force, and considering contact at the 2 interocclusal distances (0-100 and 0-200 µm). Images obtained using the 3 methods were analyzed using ImageJ software. Test-retest reliability was assessed by the intraclass correlation coefficient (ICC) and validity by Pearson correlations. RESULTS: ICCs ranged from 0.56 to 0.79 (p < 0.001) for the T-scan; 0.37 to 0.61 (p < 0.05) for 3D surface scan; and 0.92 to 0.95 (p < 0.0005) for occlusal registration. The highest OCA values were obtained using the T-scan, and the lowest using the 3D surface scan. Occlusal registration measurements had the highest correlations with those of the other techniques. CONCLUSIONS: T-scan is a reliable method for measuring the OCA, but the 3D surface scan is not. Occlusal registration showed a high validity.

Changes in masticatory laterality 3 months after treatment with unilateral implant-supported fixed partial prosthesis.

OBJECTIVE: This study assessed changes in masticatory laterality in patients with unilateral posterior missing teeth 3 months after treatment with an implant-supported fixed partial prosthesis (ISFPP). METHODS: Thirty patients with unilateral posterior missing teeth participated in this prospective study. They were treated with one-, two- or three-unit ISFPPs. The control group comprised 10 healthy individuals with complete natural dentition. Each participant performed masticatory assays at baseline and at 3-month follow-up, chewing pieces of silicon inside a latex bag. Masticatory laterality was determined using three different methods: assessment of the first chewing cycle, of all cycles and application of a visual analogue scale. Data were compared using the Kruskal-Wallis or the Mann-Whitney U test as appropriate. RESULTS: Three months after treatment, a significant change in the asymmetry index towards the treated side and a significant reduction in the Unilateral Chewing Index were observed in the ISFPP group. No significant differences in masticatory laterality between groups were detected at 3-month follow-up, regardless of the method assessed. CONCLUSION: Treatment with ISFPPs alters the masticatory laterality, moving it to the treated side and increasing the degree of bilateral chewing in patients with unilateral posterior missing teeth.

Experience with mouthguards and prevalence of orofacial injuries among field hockey players in Catalonia.

BACKGROUND/AIM: Orofacial injuries are a serious problem in field hockey. The aim of this study was to determine the prevalence of orofacial injuries in field hockey players in Catalonia, the frequency of mouthguard use, the types of mouthguards used and the degree of interference with oral function. MATERIAL AND METHODS: In this cross-sectional study, 325 field hockey players (28% women) from all age categories completed a questionnaire about orofacial injuries occurring during their sporting lives, including dental injuries, oral lacerations and episodes of acute temporomandibular disorder (TMD) pain. The questionnaire also asked about the experience of using a mouthguard, the type of mouthguard used and any adverse effects of use. The degree of interference with oral function was compared by type of mouthguard (mouth-formed, custom-made and pre-fabricated mouthguards) using the Kruskal-Wallis test. RESULTS: Half of the players (50.2%) reported at least one orofacial injury during their sporting lives. The mean number of oral lacerations, TMD pain episodes and dental injuries were 1.59, 0.24 and 0.18, respectively. In total, 310 players (95.7%) had tried a mouthguard, and of these 269 (86.8%) and 283 (91.3%) still used a mouthguard habitually during training and competition, respectively. Only 11 players (3.5%) had tried all three types of mouthguards, and 71 players (22.9%) had tried two types of mouthguard. By type, 217 players (70.0%) had tried mouth-formed (boil-and-bite) mouthguards, 156 (50.3%) had tried custom-made mouthguards and 30 (9.7%) had tried pre-fabricated mouthguards. Custom-made mouthguards were rated as more comfortable than the mouth-formed type (P < .05). CONCLUSIONS: The prevalence of orofacial injuries among field hockey players is relatively high. Most players habitually use a mouthguard during training and competition, typically preferring custom-made or a mouth-formed types. Custom-made mouthguards were considered the most comfortable.