Type Of Malocclusion Research Articles

Perception Survey of Virtual Reality Simulation with Malocclusion Models

The purpose of this study was to develop prototype of virtual reality(VR) simulation with malocclusion models and evaluate its applicability. Task abilities, task completion time, and a satisfaction survey were compared between dentist trainees and dental students. Participants were instructed to observe virtual malocclusion models and then performed three tasks to diagnose the type of malocclusion, determine clinical findings and develop treatment plans. Their satisfaction with the simulation experience were evaluated using a questionnaire containing five questions. Task abilities of trainees related to clinical features and treatment plans were significantly higher than that of students(<i>p</i> < 0.01). In both groups, the task completion time for the second case was significantly reduced compared to that for the first case(<i>p</i> < 0.01). The satisfaction survey showed high scores and positive responses for this simulation in both groups. If the prototype of VR simulation is continuously advanced, it will be applicable for orthodontic education in pediatric dentistry.

The Effect of Malocclusion on Kurdish Young Children’s Production of Dental, Labio-Dental and Alveolar Sounds: A Case study

The purpose of the present study is to investigate the effect of malocclusion on the production of dental, labio-dental, and alveolar fricative and stop consonants. To achieve this purpose, Fifteen Kurdish young children ranging in age from 8-12 years old were selected to participate in the current study. They were distributed over three groups according to their bite-block occlusions. The participants were asked to pronounce isolate fricative and stop sounds and words which include target sounds, and their voices were recorded. Later, the patricians’ audio-recordings were analyzed via a software praat analysis (wave form and sound spectrograph). The main conclusion of the study was that the children with malocclusions had difficulties in producing the inter-dental, labiodental, and alveolar sounds properly. In addition, distocclusion, open-bite and extra orally deep-bite malocclusions were more significant than other types of malocclusions in affecting target sounds production

Angulation and Height of Canine in Different Type of Malocclusion

Angulation and Height of Canine in Different Type of Malocclusion

Orthodontic Treatment with Clear Aligners

The paradigm shift in orthodontics arrived with the introduction of Aligner System. It allows both dental practitioner and patient to develop a visual understanding of orthodontic tooth movement. The esthetic and practical advantages of the system have extended orthodontic services to a greater population. The transparency of the clear aligners enhances its esthetic appeal for those adult patients who are averse to wearing conventional labial fixed orthodontic appliances. Although guidelines about the types of malocclusions that this technique can treat exist, few clinical studies have assessed the effectiveness of the appliance.

Prevalence of Malocclusion in Patients with Thalassemia Major: A Cross-sectional Study

Background: Iran lies in the world's thalassemia belt; accordingly, the beta‐thalassemia gene is carried by 4% of the Iranian population. Due to the dearth of research and literature available on the prevalence of malocclusions in the Iranian population with beta-thalassemia major, this study was conducted to determine the prevalence and severity of facial abnormalities among patients who were referred to Bu-Ali Sina Hospital, Sari, Iran. Methods: This descriptive cross-sectional study was conducted on 200 patients with thalassemia major who were referred to the care unit of Bu-Ali Sina teaching and therapeutic Hospital, Sari, Iran, in 2018. The patients were then visited by a trained dentist who had been given the necessary theoretical and practical training. Malocclusion was classified based on Angle's classification. Spacing, overcrowding, overjet, and overbite were measured, and the distances were recorded based on a checklist. Results: The prevalence of malocclusions obtained was 87.5%, which included malocclusions of Class I (34%), Class II (31%), and Classes III (22%) amongst patients. There was no significant relationship between the type of malocclusion and gender (P = 0.77). Moreover, no significant difference was observed among patients with thalassemia major and different classes of malocclusions in terms of age both in males (P = 0.49) and females (P = 0.58). Conclusions: Malocclusions are common among adolescents and adults with thalassemia, which is not associated with age or gender. Therefore, patients should be regularly visited and followed up by a dentist to manage and control their dental problems. In addition, effective and preventive measures, as well as health education should be seriously considered in these patients.

The habit sucking thumb as the etiology factor of malocclusion: literature review

Background: Sucking thumb is a bad oral habit that may cause a dentofasial alteration that affects the process of swallowing, mastication, breathing, phonetic, densupporting structure, esthetic, and also the teeth occlusion. Objective: To show the habit of sucking thumb is the etiology factor of malocclusion. Method: Literature review was conducted by collecting various information regarding the topic and perform the synthesis. Result: From 8 scientific research, it was known that the habit of suck-ing thumbs is one of the etiology factors of malocclusion. The most common type of malocclusion found on individuals were anterior openbite, followed by Class II occlusion, increased in overjet, and crossbite posterior. Conclusion: The habit of suck-ing thumb may cause malocclusion; so that a preventive action must be taken to eliminate the habit during the development and growth stage.

English

BACKGROUND Self-satisfaction can be influenced by malocclusion resulting in impairment of psychology, associated with low self-esteem (SE) and quality of life issues (QOL). Certain malocclusions and orthodontic treatment needs are related to QOL and they can affect the psychological development and social skills of adolescents and young adults, who are the most common orthodontic patients. This study was done to assess the self-esteem and Orthognathic Quality of Life (OQL) among female participants with different types of malocclusion in private orthodontic clinics in Jeddah. METHODS This questionnaire-based study evaluated the effect of orthodontic malocclusion on SE and QOL in female orthodontic patients with Class I, Class II, Class III malocclusion, crowded anterior teeth, proclined anterior teeth, open bite, and deep bite patients. Patients were evaluated before starting orthodontic treatment with Rosenberg’s SelfEsteem Scale and the Orthognathic Quality of Life Questionnaire (OQLQ) to find any correlation with malocclusion severity. RESULTS The results indicated that females who had Class II proclination and Class II deep bite type of malocclusion had significantly higher negative SE compared to other types. In the oral function component of the OQLQ, Class II malocclusion had statistically significant higher OQLQ scores than Class I Open bite (mean difference = 6.11, P = 0.004) and Class II Deep bite (mean difference = 4.88, P = 0.015). CONCLUSIONS The results suggest that female orthodontic patients with severe Class II and / or severely protrusive lip profile, deep bite may have lower SE and QOL than those with crowding, open bite, and Class III malocclusion. KEY WORDS Self-esteem, Orthodontic Malocclusion, Female Adult Orthodontic Patients, Quality of Life

Correlation between chronological age and skeletal maturity in different malocclusions: A retrospective study

The timing of initiation and duration of the pubertal peak is important in dentofacial orthopaedics as the mandible expresses maximum growth during the pubertal peak. The aim of the study was to compare the mean chronological age with skeletal age in three skeletal jaw relations. The sample consisted of 787 cephalograms divided into class I, class II, and class III skeletal relationship, in which cervical vertebrae stages were assessed. Dunn test was used to compare different types of malocclusion. Pubertal peak duration was assessed by comparing the respective 95% CI. There was no statistically significant difference in the mean chronological age in all three malocclusion groups at CS2, CS3, CS4 and CS5. There was no significant difference in the mean age of boys and girls at each CVM stage, but class III boys have significantly delayed maturity during the pubertal spurt at CS4 (14.6 years±0.98) compared with girls (13.3 years±1.48) with P=0.02. The pubertal peak duration was 1.27 years (CI: 0.77-1.76) in the class I children, 0.96 (CI: 0.58-1.34) in the class II children and 1.15 years (CI: 0.26-2.0) in the class III children. In the class III children, the duration of the pubertal peak was higher for boys, 1.74 years (CI: 0.66-2.82) compared with girls, 0.8 years (CI: 0.42-2.82). There was positive correlation between chronological age and CVM stages in each skeletal jaw relation. Average time of attaining of a pubertal spurt is similar in class I, class II and class III children. Class III girls reach puberty slightly earlier than boys and puberty ends lately in class III boys. Class II boys have the shortest duration of the pubertal peak and class III boys have the longest duration of the pubertal peak.

Evaluation of smile esthetics in adults with different overjets

Our aim was to quantitatively assess the relationship of smile esthetics variables with various types of anterior overjet (OJ) malocclusion, and identify the cephalometric factors affecting smile measurements in different types of anterior overjet malocclusion. 90 patients undergoing orthodontic treatment in the Department of Orthodontics were selected for this retrospective study based upon the inclusion criteria. The patients were divided into the following groups according to their OJ: Group 1 (0-4mm), Group 2 (>4mm), Group 3 (<0mm).The upper lip height, and inter-labial gap differed significantly among the groups, whereas arc ratio, tooth number, upper midline, buccal corridor, smile index, arch form index and lower tooth exposure did not significantly among the groups. Some smile variables (upper lip height, inter-labial gap) differed significantly among different types of anterior overjet malocclusion. This study confirmed that the smile pattern varies between different types of malocclusion.

Prevalence of TMD among Children Provided with Fixed Orthodontic Treatment.

BackgroundAccording to available scientific references and textbooks, there are contradictory views concerning the etiology of signs and symptoms of TMD.ObjectivesThe aim of this study was to determine a correlation between the incidence of signs and symptoms of TMD in children aged 12-18 who do not wear a fixed orthodontic appliance and the incidence of signs and symptoms of TMD in children who wear a fixed orthodontic appliance.Material and MethodsThe total number of 120 subjects were included in this survey and divided into two groups. There were 60 respondents in the experimental group that consisted of 30 boys and 30 girls with different types of malocclusion, who were treated with a fixed orthodontic straight wire technique. The remaining 60 respondents, which was a group that also consisted of 30 boys and 30 girls, were patients with neutroclusion.ResultsThe results of the study have shown that the TMJ clicking sound symptom, the most common symptom of TMD, occurs with almost equal prevalence in both groups of respondents; specifically, 56.4% in orthodontic patients, and 46.6% in the control group respondents. A statistically significantly higher percentage of female respondents in both groups have experienced headache problems (p <0.03).ConclusionOn the basis of the statistics obtained as a result of this research, we can come to the conclusion that there is no correlation between the fixed orthodontic treatment and the development of signs and symptoms of TMD.

Use of Immunofluorescence Technique to Perform a Quantitative Analysis of Masseter Muscle Fibers in Unilateral Posterior Crossbite: A Pilot Study

Unilateral posterior crossbite is a type of malocclusion that involves morpho-functional characteristics of masticatory muscle, such as the masseter: electrophysiological data have shown that the affected side works less than the contralateral muscle, which shows a normal or increased activity, probably in order to compensate for the affected side. The aim of present work was to measure the diameter and the cross-sectional area of ipsilateral and contralateral muscle fibers to verify if hypertrophy and/or hypotrophy take place in this malocclusion. We used immunofluorescence pictures to measure, using ImageJ software, the diameter and the cross-sectional area of fibers from control and crossbite groups; after that, the data were processed to perform statistical analyses. Results show that the fiber diameters of contralateral muscle are larger than the diameters of ipsilateral and control fibers, and that this difference is statistically significant. No statistically significant difference was found between the fiber diameters of the ipsilateral and control muscles. All these data suggest that, during unilateral posterior crossbite, morphological changes take place in the contralateral masseter muscle, which undergoes hypertrophy, probably to compensate for the low activity of the affected muscle.

Relationship between the Types of Malocclusion and the Localization of Headaches in Adults

The aim of this study was to investigate the manifestations of headaches in adult patients with types of malocclusion and occlusion deformities. Methods and Results: The study was conducted in 171 adult patients (43 men and 128 women) with malocclusion and occlusion deformities at the age of 18 to 62 years old, who were examined in the orthopedic dentistry clinic. The nature of the dentition closing was studied directly in the patient's oral cavity, and with the help of the "Gnatomat" universal articulator on diagnostic plaster models of the jaws. The occlusal relationships of the teeth were analyzed in the position of the central, anterior, lateral and dynamic occlusions. The biomechanics of the lower jaw movements were studied in 3 mutually perpendicular directions. The detected anomalies and deformities of the occlusion were grouped as sagittal, transversal and vertical. Each group was diagnosed as independent forms of malocclusion, and combined with other anomalies and deformities of the dentoalveolar system. All the subjects were asked to answer the questions of a questionnaire specially developed for our study. The unified questionnaire was developed based on a modified rating questionnaire and the determination of the life disorders index in neck pain. The questionnaire includes blocks of questions aimed at identifying the localization of the headache in the temporal, parietal (in one or both) regions, occipital, frontal regions and in the longitudinal seam region. We identified complaints of patients with pain in adjacent regions of the head. Of the 171 examined adult patients with malocclusion and occlusion deformities, 99 (57.9%) complained of headaches. The presence of a headache in the parietal region of the head was associated most often with sagittal and transversal malocclusions. The presence of a headache in the temporal part of the head was associated often with vertical malocclusion The results of correlation analysis showed that pain in 2 regions of the head was associated with malocclusion: the temporal region (rb=0.9892, P=0.0013) and parietal region (rb=0.9712, P=0.0058). Other regions were not statistically significantly associated with malocclusion. Conclusion: There is a certain relationship between the types of malocclusion, occlusion deformities and localization of headaches in adults. Headaches in the parietal and temporal regions of the head are associated with malocclusion and occlusion deformities more often. The obtained data can serve as a basis for the development of recommendations for appropriate corrective measures in orthodontic practice.

Maxillary expansion methods

Gustė Markevičiūtė1, Vilija Berlin1,2 1Institute of Dentistry, Faculty of Medicine, Vilnius University, Vilnius, Lithuania 2Vilnius University Hospital Zalgiris Clinic, Vilnius, Lithuania Abstract Background. Posterior crossbite is a common malocclusion usually caused by insufficient growth of maxilla. In Lithuania, the prevalence of crossbite during mixed or early permanent dentition is approximately 30%. Generally, posterior crossbite does not cause any pain or chewing difficulties in children, though, if not treated, it can lead to abnormal movement of the mandible, strain of the temporomandibular joint, skeletal facial assymetry or obstructive sleep apnea. This type of malocclusion usually does not self-correct, so orthodontic maxillary expansion is needed. Maxillary expansion technique is dependent on patient’s age and his midpalatal suture ossification level. Aim: to analyze the scientific literature about treatment of posterior crossbite and maxillary expansion methods. Methods: literature sources were selected from PubMed and Cochrane Library scientific databases, using the keywords in the original language: “posterior crossbite“, “maxillary expansion“, “palatal expansion“. Results: 31 publications were analyzed on the subject of posterior crossbite and maxillary expansion methods. Conclusions. The following methods of maxillary expansion can be distinguished: slow or rapid maxillary expansion, surgically assisted rapid palatal expansion and mini-implant assisted rapid palatal expansion. Method selection depends on patient’s age and skeletal maturity. The most important factor is midpalatal suture ossification level. Keywords: posterior crossbite, maxillary expansion, palatal expansion. https://doi.org/10.53453/ms.2021.06.19

Evaluation of self-perceived pain and jaw function impairment in children undergoing slow and rapid maxillary expansion.

To evaluate and compare perceived pain and jaw function impairment during the first 4 weeks with slow maxillary expansion (SME) using quadhelix and rapid maxillary expansion (RME) using conventional banded hyrax. Sixty patients aged 10.2 to 15 years were enrolled and consecutively recruited to either the quadhelix group (QG) or hyrax group (HG). A questionnaire was used to evaluate pain, jaw function impairment, and analgesic consumption in the first 7 days, at 2 weeks, and at 4 weeks. Fifty-five patients (43 girls and 12 boys) completed the questionnaire at all time points (27 in the QG and 28 in the HG). Except at 4 hours, there were no significant differences between the groups regarding pain from teeth, tongue, and palate. Patients started to adapt after day 3. Patients in the HG group reported significantly higher scores for difficulty in swallowing (moderate to severe) during the first 6 days. In both groups, minimal effects were found on speech and the majority of patients did not experience difficulty in yawning or laughing. There was no significant difference in analgesic consumption between the groups. No correlations were found between age, gender, or malocclusion type and any of the investigated outcomes. Quadhelix for SME and conventional banded hyrax for RME were well tolerated by patients after 1 week. The decision to use either appliance could be based on factors not related to patient experiences.

Dental health status and hygiene in children with cerebral palsy: A matched case-control study.

Children with cerebral palsy (CP) are at risk for oral pathology and parafunctional habits, and are reliant on caregivers for oral hygiene. To evaluate oral hygiene habits and oral examination findings among a group of children with CP and a healthy age- and gender-matched control group. A comparative, cross-sectional study, consisting of a questionnaire component and a standard dental examination component, each applied to both groups. Eighty-three children with CP and 84 healthy children were included. Parents of children with CP were more likely to be of low educational level and lack a professional line of occupation (P<.05). Children with CP were less likely to be responsible for oral hygiene maintenance, adhere to toothbrushing, or receive procedural dental care (P<.001). Food packing and drooling were significantly more likely in children with CP. Malocclusion type III was more prevalent among children with CP, as was higher gingival index and gingival enlargement index-horizontal component (P<.001). There were no differences in caries experience between the CP and control groups. Children with CP have suboptimal oral hygiene habits, limited access to procedural dental care, higher parafunctional habits, and increased periodontal pathology.

Extracellular Matrix Behaviour in Masseter Muscle of Patients Affected by Unilateral Posterior Crossbite: An Immunofluorescence Study

Unilateral posterior crossbite is a malocclusion disease that involves morpho-functional characteristics of masseter muscle; a normal or increased activity of contralateral muscle and a reduced activity of the ipsilateral muscle during unilateral crossbite have been shown. Since the extracellular matrix plays a key role in in mechano-transduction of transmitting forces during muscle contraction, the aim of the present study was to analyse the behaviour of extracellular matrix in this type of malocclusion through immunofluorescence reactions against laminin, collagen IV, MMP-2 and MMP-9. Our results show an increased expression of Laminin, Collagen IV, and MMP-9 in the contralateral side if compared to the ipsilateral side. No differences have been found in MMP-2 expression between contralateral and ipsilateral muscles. Since the increased expression of Laminin, Collagen IV and MMP-9 is associated with muscle hypertrophy and MMP-2 is associated with muscle atrophy, our results support the existence of a hypertrophic response of contralateral muscle during unilateral posterior crossbite that probably aims to compensate the altered function of the ipsilateral one.

The Radiological Assessment of Root Features and Periodontal Structures in Endodontically Treated Teeth Subjected to Forces Generated by Fixed Orthodontic Appliances. A Prospective, Clinical Cohort Study.

The various side effects of orthodontic treatment with fixed orthodontic appliances (FOAs) and their impact on apical and periodontal structures have been widely reported. However, the existing data is not yet conclusive. Aims and objectives: To investigate the status of roots and periodontium in endodontically treated teeth that have undergone orthodontic treatment with the use of FOAs and to evaluate their impact on apical/periodontal structures. Material and methods: The prospective clinical cohort study initially involved 69 participants aged 16–40, without underlying systemic conditions, who received orthodontic treatment with ligatureless FOA systems due to different types of mild and moderate malocclusions. To meet the required criteria, 88 teeth in 34 patients were assessed clinically and radiologically. Participants had at least one tooth treated endodontically while the corresponding tooth from the same anatomical group on the opposite side was vital and intact (a ‘split-mouth’ approach). Four cohorts were allocated: Group IA consisted of 15 teeth, treated utilising the principles of modern endodontics, that were subjected to orthodontic forces no less than six months after completing the root canal obturation. Group I consisted of 13 similarly endodontically treated teeth, which commenced orthodontic treatment at least six months after the completed endodontic therapy. Group II contained 16 teeth treated by conventional endodontic methods and the control group, Group III, contained 44 clinically and radiologically intact teeth (incisors and premolars) with vital and sound dental pulp. The response of apical and periodontal structures to FOAs was determined by data collected from intraoral periapical radiographs taken within the course of five consecutive appointments during the orthodontic treatment. Results: No statistically significant differences were observed in susceptibility to FOA-induced external apical root resorption (EARR) between combined Groups IA + IB and II. An association was, however, demonstrated, between the occurrence of EARR and the degree of expansion of the periodontal ligament (PDL) space, regardless the method of root canal treatment. Cumulative data revealed a positive correlation between the width of the PDL space and the stage of FOA treatment (the third and the fourth appointment). The subtle changes in radiological length of roots have been observed (min 0 mm/max 0.38 mm), particularly between the second and third appointment in Group II (p < 0.05). Conclusions: The standard orthodontic therapy with FOAs is a safe option with predictable outcome for persons who have recently received endodontic therapy. The anterior teeth, predominantly incisors, were more susceptible to minimal EARR than premolars, which suggests that the rate of EARR occurrence may depend upon the original morphology of the apical portion of the root. The use of additional orthodontic forces increases the risk of EARR and is associated with a higher incidence of radiologically detected PDL space widening.

Preliminary study of articulatory characteristics in open bite subjects revealed by 3T magnetic resonance imaging movies

Objectives: Previous studies have reported that articulatory dysfunction accompanied by a certain type of malocclusion can be improved by orthodontic treatment. We developed a 3-T magnetic resonance imaging (MRI) movie method with tooth visualization that can display the dynamic movement of articulation without radiation exposure. To the best of our knowledge, there is currently no report on the possible differences in articulatory movement between subjects with a normal occlusion and those with malocclusion using the 3T MRI movie method. Thus, the objective of this study was to examine the articulatory difference between subjects with a normal occlusion and those with an open bite using an MRI movie. Materials and Methods: Twenty healthy adult females, ten with a normal occlusion and ten with an anterior open bite were recruited. The overbite of the open bite subjects was zero or smaller, and all of them exhibited a tongue-thrusting habit during swallowing. A turbo spin echo image with a contrast medium was used to visualize the anterior teeth, and articulatory movement during articulation of the vowel-consonant-vowel syllable (/asa/) was scanned. The difference in tongue movement between subjects with a normal occlusion and those with an open bite was compared by measuring seven variables. Moreover, the distance between the incisal edge and the tongue apex during articulation of /s/ and the speech duration were compared. Furthermore, frequency analysis on /s/ by fast Fourier transform power spectrum was performed. Results: The tongue apex of the open bite subjects moved more anteriorly than that of the normal subjects. However, there was no significant difference in the phonetic analysis between subjects with a normal occlusion and those with an open bite. Conclusion: The 3-T MRI movie was an efficient method to quantify articulatory tongue movements. Although there was a difference in tongue movement during swallowing between subjects with a normal occlusion and those with an open bite, the difference in the articulatory tongue movements was minimal, suggesting it could be a functional compensation.

English

BACKGROUND To provide efficient and well-planned orthodontic treatment orthodontists must be able to assess the type of malocclusion and the complexity involved in its treatment. Hence, the purpose of this study was to validate index of orthodontic treatment complexity (IOTC) as a reliable index to assess the treatment complexity in treating different malocclusion groups. METHODS A retrospective study with sample of 120 pairs of orthodontic study model consisting of treated and untreated cases, were collected and equally divided into class I, class II including both division 1 and division 2 and class III malocclusions based on Angles system of classification of malocclusion. Study casts were scored according to criteria given by the index of orthodontic treatment complexity and the degree of complexity is established for each of the malocclusion groups and the occlusal traits. RESULTS The Spearman correlation coefficients test shows that occlusal traits like overjet, centreline discrepancy, molar correction, overbite, crowding, posterior cross bite, alone significantly correlated with degree of complexity. Multiple regression analysis and one way ANOVA tests were performed for the three types of malocclusion and the test showed that in individual classes of malocclusion, the predictor variable (occlusal traits) significantly predicts the degree of complexity in class I and class II malocclusion cases, but not in class III. CONCLUSIONS Overjet, centreline discrepancy, molar correction, overbite, crowding, posterior cross bite correlated with degree of complexity. IOTC forecasts the degree of complexity in class I and class II malocclusion cases, but not in class III. KEY WORDS IOTC, Malocclusion, Occlusal Traits

Effect of sleep-disturbed breathing on maxillofacial growth and development in school-aged children

ABSTRACT Purpose : In children, snoring and apnoea cause impairments in growth, cognitive function, attention, and school performance. In this study, we aimed to identify the association between craniofacial disharmony and paediatric sleep-disordered breathing. Materials and Methods : Forty-one patients with malocclusion (19 boys; 22 girls; mean age, 10.0 ± 2.1 years) were selected from our hospital. The relationship between maxillofacial morphology, pharyngeal airway form, and nasal respiratory function was examined using cephalometric analysis and skeletal patterns. All patients underwent portable monitoring with an overnight out-of-centre sleep testing protocol that could be performed at home using a portable computerized monitoring system. Results : The respiratory disturbance index was significantly greater in patients with mandibular retrusion than those with malocclusion. Arterial oxygen saturation and nasopharyngeal area were significantly smaller in participants with Class II malocclusion than in those with other types of malocclusion. Moreover, dental cast model analyses confirmed that patients with reduced transverse maxillary dimensions had a higher obstructive sleep apnoea syndrome (OSAS) risk than those with malocclusion. Therefore, patients with mandibular retrusion have a higher OSAS risk than those with other types of malocclusion. Conclusion : Childhood maxillofacial morphology may influence adult OSAS, and early treatment for children with OSAS may help prevent adult OSAS.