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.

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).

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).

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.

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.

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.

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.

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.

Do implant-supported fixed partial prostheses improve masticatory performance in patients with unilateral posterior missing teeth?

OBJECTIVES: The purpose of this study was to determine the improvement in masticatory performance and satisfaction with chewing ability in partially edentulous patients after treatment with an implant-supported fixed partial prosthesis (ISFPP). MATERIAL AND METHODS: This prospective study included 30 patients (mean age 59 years; 17 women) with unilateral posterior missing teeth treated with one-, two- or three-unit ISFPPs and 10 healthy individuals (mean age 36 years; 8 women) with complete natural dentition to establish the normal levels of mastication. Three variables were determined at baseline and at 3-months' follow-up in all participants: masticatory performance according to the median particle size (MPS) during freestyle mastication and unilateral mastication on each side, and satisfaction with chewing ability using a visual analog scale. Paired samples t test and Kruskal-Wallis test were used for intra-group and inter-group comparisons. RESULTS: The MPS following freestyle mastication decreased significantly at 3 months in both groups. Significant reductions of 21%, 30%, and 42% in the MPS were obtained from unilateral mastication on the treated side after treatment with 1, 2, or 3 restorative units, respectively. Three months after ISFPP, satisfaction with chewing ability improved by 40% in the treatment group. CONCLUSIONS: Freestyle masticatory performance may improve slightly within three months of treatment with an ISFPP and may be similar to that of subjects with complete natural dentition. Patients may obtain a 21%-38% improvement in unilateral mastication on the treated side and a 26%-54% improvement in satisfaction with chewing ability.

Satisfaction of patients with amyotrophic lateral sclerosis with an oral appliance for managing oral self-biting injuries and alterations in their masticatory system: A case-series study.

STATEMENT OF PROBLEM: About 10% of patients with amyotrophic lateral sclerosis (ALS) are candidates for oral treatment specifically because of traumatic injuries in the lips, cheeks, or tongue due to self-biting. However, patients with ALS have a prevalence of temporomandibular disorder (TMD) similar to that in the general population. PURPOSE: The purpose of this case-series study was to determine the degree of satisfaction of patients with ALS with an oral appliance for managing oral self-biting lesions or symptoms related to TMDs. This study also assessed the degree of improvement of the chief complaint and the compliance with and adverse effects of this treatment. MATERIAL AND METHODS: Eleven patients with ALS who sought oral treatment because of oral self-biting or TMD-related symptoms were included. A custom complete-coverage acrylic resin device was fabricated and fitted to each participant. A follow-up visit was planned for 3 months after the placement of the oral appliance, at which point the patients would rate the degree of improvement or worsening of the chief complaint and their degree of satisfaction with the treatment. A 1-sample t test was used to assess whether the degree of improvement of the chief complaint was significant. RESULTS: Participants reported a mean of 61% (95% confidence interval [CI] 38% to 84%) improvement of the chief complaint and a mean of 84% (95% CI 72% to 97%) satisfaction with the treatment. The mean rate of compliance was 62% (95% CI 40% to 84%) of the recommended time, and only a few adverse effects were reported. CONCLUSIONS: Participants with ALS were highly satisfied with the use of an oral appliance to manage oral self-biting or TMD-related symptoms. Adherence to this treatment was high, and no major adverse effects were observed.

Satisfaction with shortening the palatal extension of a mouthguard for water polo players: A randomized crossover study.

BACKGROUND/AIM: Approximately 50% of water polo players have suffered orofacial injuries. However, fewer than 8% of players wear a mouthguard. A more comfortable mouthguard design is therefore needed to increase compliance. The aim of this study was to assess the effect of reducing the palatal extension of a custom-made mouthguard on the degree of satisfaction with a mouthguard among water polo players. MATERIALS AND METHODS: Eighteen elite water polo players participated in this randomized crossover trial. Two custom-made mouthguards were fabricated for each participant using 4-mm-thick ethyl vinyl acetate foils, defined by the extension of the palatal margin from the cervical line: conventional (6 mm) and shortened (2 mm). The mouthguards were worn during all training sessions and matches, in a randomized sequence (one mouthguard type for the first and fourth weeks and the other for the second and third weeks). Mouthguards were evaluated on 10-point scales for discomfort, interference with oral functions, protection, and general satisfaction after each training session or match. RESULTS: Players evaluated the shortened mouthguard as having less interference with speech (Effect 1.30; P < 0.001), breathing (Effect 0.98; P = 0.004), swallowing (Effect 1.30; P < 0.001), and athletic performance (Effect 0.61; P = 0.03) compared with the conventional mouthguard. The perceived degree of protection was similar among participants when wearing each type of mouthguard. Overall, players were more satisfied with the shortened mouthguard (Effect 0.64; P = 0.03). CONCLUSIONS: Reducing the palatal extension of a custom-made mouthguard from 6 to 2 mm improves the overall satisfaction of elite water polo players without affecting the perceived degree of protection.

Risk of orofacial injuries and mouthguard use in water polo players.

BACKGROUND/AIM: The incidence of orofacial injuries and the use of mouthguards in water polo players have not been well established. The aim of this study was to determine the incidence of orofacial injuries in water polo players. Frequency of mouthguard use, the types of mouthguards used and the degree of interference with oral functions were also assessed. MATERIAL AND METHODS: In this cross-sectional study, 347 water polo players completed a questionnaire about the orofacial injuries suffered in the 2015-2016 season and the experience of using a mouthguard, such as the type of mouthguard used and the degree of interference with oral functions. RESULTS: In the 2015-2016 season, 57.9% of the players reported at least one orofacial injury, with mean numbers of 2.7 oral lacerations, 0.4 episodes of temporomandibular pain and 0.06 dental injuries. Among the 35 players (10.1%) who had tried a mouthguard, only four (1.2%) used it habitually. Some players had tried more than one type of mouthguard; 26 had tried the mouth-formed type; 11 the custom-made type; and 7 the prefabricated mouthguard. Custom-made mouthguards were rated as more comfortable than the mouth-formed type (P < 0.05). The main disadvantages of mouth-formed mouthguards were interferences with speaking, breathing and swallowing. CONCLUSIONS: The incidence of orofacial injuries in water polo players is high. Although some players had tried a mouthguard, mainly the mouth-formed type, most of them do not wear them routinely for training and competition.

Status of Removable Dentures and Relationship with Oral Candida-Associated Factors in a Geriatric Population in Catalonia.

PURPOSE: Colonization by Candida is related to wearing a denture. How denture type, status, and maintenance play a role in determining Candida colonization remains unknown. This work evaluated removable denture status in an elderly population and explored the association between denture-related factors and oral Candida colonization as determined by systemic and local factors. MATERIALS AND METHODS: Socio-demographic, general health, and behavioral data and oral factors were registered by means of a questionnaire. Oral, dental, and denture-related factors were assessed by clinical examination, and yeasts were isolated from oral and denture specimens. Multiple logistic regression analysis was used to explore the relative relevance of risk factors. RESULTS: Overall, 52.4% of subjects used complete dentures in both lower and upper arches, and 90% of the prostheses were in good condition. Denture plaque index was high in most cases, and 75% of subjects had yeasts in their oral cavities. Oral Candida colonization was significantly associated with low saliva pH, sugar consumption, and the fault of a denture component; however, only sugar consumption was found to be an independent factor related with oral Candida colonization, showing an odds ratio of 3.04 in a multiple logistic regression model. CONCLUSIONS: Elderly people in this study used a complete denture in good condition, with a median age of 15 years. Daily or weekly sugar consumption was found to be highly associated with oral colonization by Candida.

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.

Five years of sleep apnea treatment with a mandibular advancement device. Side effects and technical complications.

OBJECTIVE: To determine the variation in prevalence of temporomandibular disorders (TMD), other side effects, and technical complications during 5 years of sleep apnea treatment with a mandibular advancement device. MATERIALS AND METHODS: Forty patients diagnosed with obstructive sleep apnea received an adjustable appliance at 70% of the maximum protrusion. The protrusion was then progressively increased. TMD (diagnosed according to the Research Diagnostic Criteria for TMD), overjet, overbite, occlusal contacts, subjective side effects, and technical complications were recorded before and a mean of 14, 21, and 58 months after treatment and analyzed by the Wilcoxon test (P < .05). RESULTS: Fifteen patients still used the oral appliance at the 5-year follow-up, and no significant variation in TMD prevalence was observed. Subjective side effects were common, and a significant reduction was found in overjet, overbite, and in the number of occlusal contacts. Furthermore, the patients made a mean of 2.5 unscheduled dental visits per year and a mean of 0.8 appliance repairs/relines per year by a dental technician. The most frequent unscheduled visits were needed during the first year and were a result of acrylic breakage on the lateral telescopic attachment, poor retention, and other adjustments to improve comfort. CONCLUSIONS: Five-year oral appliance treatment does not affect TMD prevalence but is associated with permanent occlusal changes in most sleep apnea patients during the first 2 years. Patients seek several unscheduled visits, mainly because of technical complications.