Oral breathing and head posture

OBJECTIVE: To determine the head posture and cephalometric characteristics in oral breathing children. MATERIALS AND METHODS: Lateral cephalograms taken in natural head posture of 35 oral breathing patients (OB) (mean age 8.8 +/- 2.2 years SD; range 5-13 years) and of 35 patients with varied malocclusions and physiological breathing (PB) (mean age 9.7 +/- 1.6 years SD; range 7-13 years) were examined. RESULTS: A Student's t-test showed that an increase in angles NSL/OPT (P = .000), NSL/CVT (P = .001), FH/OPT (P = .000), FH/CVT (P = .005), and NSL/VER (P = .000); a decrease in the distance MGP-CV1p (P = .0001); and a decrease in the angles MGP/OP (P = .000) and OPT/ CVT (P = .036) were found in the OB group. A low position of the hyoid bone (H-MP, P = .009), a major skeletal divergence (ANS-PNS/Go-Me, P = .000), and an increased value of the ANB angle (P = .023) were present in OB patients. To ascertain if the changes in posture were connected with posterior obstruction of the upper respiratory airways, the OB group was divided into two subgroups based on the distance Ad2-PNS being greater than or less than 15 mm. No significant differences were found between these two groups. CONCLUSIONS: Our data suggest that OB children show greater extension of the head related to the cervical spine, reduced cervical lordosis, and more skeletal divergence, compared with PB subjects.     

Changes in natural head position observed immediately and one year after rapid maxillary expansion

Rapid maxillary expansion (RME) has been shown to increase nasal permeability and reduce nasal airway resistance. A number of studies have examined the relationship between RME and the change in airway resistance, or the relationship between airway resistance and natural head position (NHP). Few studies, to date, have examined the relationship between RME and the change in NHP resulting from the consequent change in airway resistance. A sample of 43 adolescent patients with uni- or bilateral crossbite in the permanent dentition underwent RME as part of normal orthodontic treatment. Cephalograms in NHP were taken before, immediately after expansion, and one year after RME. No significant changes in the craniofacial angles were observed immediately after expansion. One year post-expansion, however, NSL/VER had reduced by 3.14 degrees (P < 0.01), OPT/HOR by 2.13 degrees (P < 0.05), and CVT/HOR by 2.55 degrees (P < 0.05). The results of this study suggest an ongoing change in head posture possibly due to a change in the mode of breathing from oral to nasal as a result of RME, thereby contributing to a change in craniofacial development, supporting and adding to the soft tissue stretching hypothesis.     

Effect of low pull headgear on head position

Objective

To evaluate changes in head position following the use of low pull headgear (LHG) and compare these changes with an untreated control group.

Subjects and methods

The test group comprised pre-treatment and post-treatment lateral cephalograms of 30 males, aged 11 ± 1.5 years, who were receiving LHG therapy for correction of Class II malocclusion. Pre-observation and post-observation lateral cephalograms of 25 untreated male subjects, aged 11 ± 1.6 years, served as controls. The average treatment time for the treatment group was 12 ± 2.02 months and the average observation period for the control group was 11 ± 1.03 months. Four postural variables (NSL/CVT, NSL/OPT, CVT/HOR, OPT/HOR) were measured to evaluate the head position in all subjects pre- and post-observations.

Results

There was no significant difference in all the measurements concerning the head position within each group (p > 0.05). The mean differences of pre- and post-observations of 4 postural variables in the LHG group were 1.43, 0.9, −1.13, and −1.08, while those of the control group were 1.56, −0.32, −0.24, and 0.04, respectively. There was no significant difference between the headgear and control groups for any of the postural variables measured (p = 0.924, 0.338, 0.448, and 0.398, respectively).

Conclusions

Although postural variables showed considerable variability in both groups, head position exhibited no significant changes over a period of 11–12 months either in the control or headgear group.     

Relationships of sagittal skeletal discrepancy,natural head position,and craniocervical posture in young Chinese children

Objective: The aim of this study was to investigate the relationships of sagittal skeletal discrepancy, natural head position (NHP), and craniocervical posture in young Chinese children with average vertical facial pattern.

Methods: Ninety patients with average Frankfort mandibular plane angle (FH/ML) were classified into skeletal class I, II, and III relationships according to their ANB angle. Cephalometric radiographs in NHP were taken. Variables representing sagittal and vertical craniofacial morphology, head posture, and craniocervical posture were measured and compared.

Results: Subjects in the skeletal class II group showed the largest craniovertical angles and craniocervical angles, while subjects in the skeletal class III group exhibited the smallest craniovertical angles and craniocervical angles, though not all the measurements showed significant differences. The angle formed by the nasion-sella line and the tangent to the posterior border of the mandibular ramus (NSL/RL) was largest in the skeletal class II group and smallest in the skeletal class III group (p?=?0.05).

Discussion: Significant differences exist in NHP and craniocervical posture among skeletal class I, II, and III relationships in young Chinese children. Subjects with skeletal class II relationship tended to exhibit more extended head, and children with skeletal class III relationship often exhibited flexed head.     

Relationships of vertical facial pattern,natural head position and craniocervical posture in young Chinese children

Objective: To investigate relationships of vertical facial patterns, natural head position (NHP), and craniocervical posture in young Chinese children with skeletal Class I relationship.

Methods: Ninety-four patients with skeletal Class I relationship were classified into low, average, and high angle groups according to their mandibular plane angle (NSL/ML). Cephalometric radiographs in NHP were taken. Variables representing vertical and sagittal craniofacial morphology, head posture, and craniocervical posture were measured and compared.

Results: Inclinations of the mandible to the true vertical and cervical column were smallest in the high angle group and largest in the low angle group. Other variables representing head posture and craniocervical posture were largest in the high angle group, smallest in the low angle group. Inclinations of ramus to cervical column were largest in the high angle group and smallest in the low angle group.

Discussion: Subjects with large NSL/ML angles showed extended head and craniocervical posture, while subjects with small NSL/ML angles exhibited flexed head and craniocervical posture.     

Bullying in orthodontic patients and its relationship to malocclusion,self-esteem and oral health-related quality of life

Abstract

Objectives: To measure the self-reported frequency and severity of bullying amongst patients referred for orthodontic treatment and to investigate whether there is a relationship between levels of self-reported bullying, malocclusion and need for orthodontic treatment and an individual’s self-esteem and oral health-related quality of life (OHRQoL).

Design and setting: Cross-sectional study of an adolescent group referred for orthodontic assessment at three UK hospitals.

Subjects and methods: Three hundred and thirty-six participants aged between 10 and 14 years were recruited. Validated questionnaires were used to measure the self-reported frequency and severity of bullying, self-esteem and OHRQoL. Orthodontic treatment need was assessed using IOTN.

Results: The prevalence of bullying was 12·8%. Being bullied was significantly associated with Class II Division 1 incisor relationship (P?=?0·041), increased overbite (P?=?0·023), increased overjet (P?=?0·001) and a high need for orthodontic treatment assessed using AC IOTN (P?=?0·014). Bullied participants also reported lower levels of social competence (P<0·001), athletic competence (P<0·001), physical appearance related self-esteem (P<0·001) and general self-esteem (P<0·001). Higher levels of oral symptoms (P?=?0·032), functional limitations (P<0·001), emotional (P<0·001) and social impact (P<0·001) from their oral condition, resulting in a negative impact on overall OHRQoL (P<0·001), were also reported.

Conclusions: Significant relationships exist between bullying and certain occlusal traits, self-esteem and OHRQoL.     

The effect of a mandibular advancement appliance on cervical lordosis in patients with TMD and cervical pain

Aims:

A preliminary study to compare cervical lordosis by means of cervical cephalometric analysis, before and after six months of continuous mandibular advancement appliance (MAA) use, and to show how physical therapy posture re-education would improve the cervical lordosis angle.

Methodology:

Twenty-two female patients with temporomandibular disorders (TMD) and cervical pain with lordosis <20° were included. Patients had to have a muscle pain history for at least six months, and with an intensity ≥6, measured by means of a visual analog scale (a horizontal 0–10 numeric rating scale with 0 labeled as ‘no pain’ and 10 as ‘worst imaginable pain’). Patients had to present the angle formed by the posterior tangents to C2 and C7 of equal or less than 20°. Cephalometric and clinical diagnostics were performed initially (baseline) and at the end of the study period (six months). During the third month with MAA treatment, a physical therapist evaluated the postural deficit and performed a program of postural re-education. Angular and linear dimension data presented a normal distribution (P>0·05; Shapiro Wilk Test), so the paired comparison of the cephalometric measurements was made by t-test for dependent samples.

Results:

Angle 1 (OPT/7CVT); angle 3 (CVT/EVT) and angle 4 (2CL/7CL) showed a significant increase in the cervical lordosis. Angle 2 (MGP/OP), angle 5 (HOR/CVT) and the distances C0–C2 and Pt–VER, presented no significant changes.

Conclusions:

The increase in cervical lordosis implies that six months of continuous MAA use, together with a program of postural re-education, promotes the homeostasis of the craniocervical system.     

Associations between thoracic kyphosis,head posture,and craniofacial morphology in young adults

The aim of the present study was to investigate associations between thoracic hyper- and hypokyphosis, head posture, and craniofacial morphology in young adults. Using forward bending test and spinal pantographic measurements, 31 subjects, 16 with thoracic hyper- and 15 with hypokyphosis, were selected from a population-based cohort of 430 young adults. Lateral roentgen-cephalograms were taken in natural head posture and craniofacial and postural angular measurements were calculated. Any statistically significant differences between the groups - thoracic hyperkyphosis and thoracic hypokyphosis - were analysed using Student's t test. Subjects with thoracic hyperkyphosis had a larger atlantocervical angle (At/CVT, P &lt; 0.01) than subjects with thoracic hypokyphosis. However, head position (NSL/VER)was similar in both groups, probably owing to the visual perception control of craniovertical relation. There was no statistically significant difference in craniofacial morphology between the groups.     

Change in cranio-cervical angulation following orthognathic surgery

Changes in natural head posture (NHP) were investigated in 33 patients (10 males, 23 females) with an age range of 16-40 years (median 21 years) following orthognathic surgery to change vertical face height. The reproducibility of the radiographer's technique of taking radiographs in NHP was investigated using a photographic method and found to be acceptable. The patients were divided into two groups: group 1, patients who had more than 3 mm of vertical change in anterior total face height (ATFH) and group 2, those who had less than 3 mm vertical change.For group 1 there was a significant relationship between ATFH change and cranio-cervical angulation (NSL/OPT) change (r = 0.532, P = 0.023), compared with group 2 (r = -0.247, P = 0.376). A similar relationship was revealed between lower anterior face height (LAFH)/ATFH ratio and NSL/OPT, where the correlation was also higher in group 1 (r = -0.635, P = 0.005) compared with group 2 (r = -0.182, P = 0.515). The correlation between cranio-vertical angulation (NSL/VER) and ATFH was not significant for group 1 (r = 0.406) or group 2 (r = 0.239) patients. Additionally, NSL/VER and LAFH/ATFH correlation for the two groups was not significant (r = -0.392 and -0.338, respectively).There appears to be a relationship between the reduction in vertical face height following orthognathic surgery and neck posture (as indicated by NSL/OPT). As no significant relationship was found between the reduction in face height and head posture (as indicated by NSL/VER) this suggests that neck posture, rather than head posture, had changed.     

Are occlusal features associated with different temporomandibular disorder diagnoses in bruxers?

Aims:

The present study was designed to test the hypothesis that dental occlusion may have a role in mediating the effects of bruxism in temporomandibular disorders (TMD) patients. It aimed to answer the clinical research question: in a population of TMD patients with clinically diagnosed clenching-type bruxism, are the different TMD diagnoses associated with different occlusal features?

Materials and methods:

A total of 294 TMD patients (73% females, mean age 38·3±9·2 years) who were positive for a clinical diagnosis of clenching-type bruxism underwent an assessment in accordance with the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) axis I, as well as a recording of nine occlusal features. Statistical analyses were performed to test the null hypotheses that: (1) no differences existed between the patients with or without the various occlusal features as for the prevalence of the various single and combined RDC/TMD group diagnoses (single variable analysis), and (2) having any specific occlusal feature makes no difference in distinguishing within the RDC/TMD diagnoses (multiple variable analysis).

Results:

The distribution of the different combination of RDC/TMD axis I diagnoses was significantly different in patients with laterotrusive interferences with respect to those without such interferences (chi-square?=?15·209; P?=?0·033) as well as in patients with a slide from retruded contact position (RCP) to maximum intercuspation (MI) >2 mm with respect to those without such slide (chi-square?=?4·029; P?=?0·012) and in those with or without molar class asymmetry (chi-square?=?17·438; P?=?0·015). Multinomial regression analysis showed that the model including the various occlusal features account for 20·4% of the variance for RDC/TMD diagnoses (Nagelkerke R²?=?0·204) and allowed the rejection of the null hypothesis that having such specific occlusal features makes no difference in distinguishing within the RDC/TMD diagnoses.

Conclusions:

Within the limitations of this study, it can be suggested that in a population of patients with TMD and clinically-diagnosed clenching-type bruxism, the patterns of TMD diagnoses may be influenced, at least in part, by the presence of some features of dental occlusion, namely, slide RCP-MI, laterotrusive interferences, and molar asymmetry.     

Changes in head posture and nasopharyngeal airway following surgical correction of mandibular prognathism

It was the aim of the present study to cast light on the role of the mandible in relation to head posture and airway space by evaluating patients before and after surgical correction of mandibular prognathism. The material comprised standardized profile cephalograms of 52 patients with mandibular prognathism. All patients had received orthodontic adjustments prior to mandibular osteotomy. Mean age of the patients was 24.3 years, and 12 males and 40 females participated in the study. The first profile radiograph of each patient was obtained the day before surgery in the natural head (mirror) position. All patients underwent mandibular surgery with a bilateral vertical ramus osteotomy. Approximately one year after surgery, the cephalometric investigation was repeated. Head posture was evaluated by the craniocervical angulation (NSL/CVT and NSL/OPT) and airway space as nasopharyngeal airway size (ad1 and ad2). Changes in posture and airway (ex.2-ex.1) were evaluated by paired t-tests. The results showed a mean increase in head posture of 2.7 degrees (p less than 0.001) and a mean reduction in airway space of 2.3 mm (p less than 0.001).     

Predictors of ethical approval and informed consent in orthodontic RCTs

Abstract

Objectives: Determine the number of orthodontic randomized controlled trials (RCTs) published in four key orthodontic journals from 1 January 2001 to 31 December 2010, whether details about ethical approval (EA) and/or informed consent (IC) were reported and identify predictors for reporting EA and IC in orthodontic RCTs.

Design: Retrospective observational study.

Setting: American Journal of Orthodontics and Dentofacial Orthopedics (AJODO), Angle Orthodontist (AO), European Journal of Orthodontics (EJO) and Journal of Orthodontics (JO) from 2001 to 2010.

Interventions: AJODO, AO, EJO and JO were handsearched to identify all RCTs published from 1 January 2001 to 31 December 2010.

Main outcome measure: The RCTs were assessed to identify: inclusion of details about EA and IC, publication journal, number of authors, number and location of centres involved, perceived statistician involvement, publication year and inclusion of random* in either the title, abstract or body of the text.

Results: 218 RCTs were published. 109 (48·6%) had reported both EA and IC, 59 (27·1%) neither and 53 (12·9%) either EA or IC. Factors associated with an RCT reporting obtaining EA and IC: number of authors (P<0·001), random* in title (P<0·001), random* in abstract but not title (P<0·001), location of origin (P?=?0·001), publication year (P?=?0·003), journal of publication (P?=?0·004) and number of centres (P?=?0·008). Logistic regression suggested the most significant indicators of reporting EA and IC were: publication in the JO (P?=?0·018), >6 authors (P<0·001), random* in the abstract but not title (P?=?0·004) and publication after 2004 (P?=?0·001).

Conclusions: RCTs were most likely to have reported EA and IC when published in the JO, after 2004 while having more than six authors and random* in the abstract but not title.     

An active,skeletally anchored transpalatal appliance for derotation,distalization and vertical control of maxillary first molars

Abstract

Objective: The objective of this investigation was to evaluate treatment outcomes of the skeletally anchored ‘Frog’ appliance. Design: A single-centre, retrospective study was performed. Setting: Private orthodontic practice. Participants: Patients who had undergone comprehensive orthodontic treatment with the skeletally anchored ‘Frog’ appliance. Methods: 43 participants (20 males and 23 females) who had received treatment with the skeletally anchored ‘Frog’ appliance where included. In order to explore dentoalveolar and skeletal treatment outcomes, pre- (T1) and post- (T2) treatment measurements were performed on patients’ plaster models and cephalometric images. Comparisons between T1 and T2 were made by means of a Student’s t-test. All statistical analyses were conducted at the 0·05 level of statistical significance. Results: Study model analysis revealed a statistically significant derotation of maxillary molars (μ_ΔT2?T1?=?9·5°, P<0·001) as well as an increase in transverse arch dimensions at the end of treatment (μ_ΔT2–T1?=?2·2 mm, P<0·001). Cephalometric changes included bodily distalization of maxillary molars (μ_Δ(T2–T1)?=??1·9 mm, P<0·001), as well as noticeable angular displacement (μ_ΔT2–T1?=?4·1°, P?=?0·004). No significant anchorage loss was observed, as displayed by the limited change in maxillary incisor position (μ_Δ(T1–T2)?=?0·2 mm, P?=?0·45). In addition, excellent vertical control of the maxillary molars was achieved, with no change in the mandibular plane (ML/NSL) angle (μ_ΔT2–T1?=?0·3°, P?=?0·38). Conclusions: The skeletal ‘Frog’ is effective in derotating and distalizing maxillary molars without anchorage loss and with excellent vertical control.     

Association between occlusal anomalies and dental caries in 3‐ to 5 year‐old Brazilian children

Abstract

Objective: To investigate the association between certain occlusal anomalies and the occurrence and severity of dental caries in Brazilian preschool children.

Design: Cross‐sectional study.

Setting: Twenty‐eight public nursery schools in Canoas, southern Brazil.

Subjects and methods: The study population comprised 890 three‐ to five‐year‐old children. Five trained and calibrated observers examined children for determination of decayed, missing and filled tooth (dmft) index (World Health Organization criteria including white spots) and orthodontic variables.

Outcome measures: Caries severity (dmft) and caries occurrence (dmft?1).

Statistical analysis: Multivariable analysis was performed using Poisson regression with robust variance in order to determine the occlusal anomalies which represent risk factors for the occurrence of the binary outcome.

Results: Caries severity was significantly higher among children without spacing in the maxillary anterior teeth (P?=?0·001) and mandibular anterior teeth (P?=?0·003) and among children without accentuated overjet (P?=?0·023). The multivariable analysis demonstrated that children without spacing in maxillary anterior teeth had an increased risk of dental caries (prevalence ratio?=?1·43; 95% CI, 1·05–1·93). Open bite, accentuated overjet and posterior cross‐bite were not associated with this outcome in the final model.

Conclusions: Absence of spacing in the maxillary labial segment represents a risk factor for dental caries in preschool children.     

Cervical lordosis in patients who underwent anterior cruciate ligament injury: a cross-sectional study

It has been proposed that intraoral devices can influence cervical posture. Cervical posture might also be influenced by stimuli from the lower limbs, such as injury of the knee. The hypothesis to be tested is that intraoral devices are useful during the rehabilitation of orthopedic patients to accelerate the restoration of postural control. This study evaluates cervical posture on lateral skull radiographs in subjects who suffered anterior cruciate ligament (ACL) injury of the left knee. Twenty adult Caucasian males (mean age 30.6+/-9.2 yrs.) with ACL injury of the left knee were compared with 40 control subjects (mean age 27.9+/-7.2) who did not show any ACL injury. Lateral skull radiographs, made in natural head position (mirror position), were obtained for all subiects. Various postural and morphological variables were individualized on each radiograph. To assess errors due to landmark identification, duplicate measurements were made of 15 radiographs and compared using the Dahlberg formula. The method error from both sources was less than 0.5 degrees for all angular measurements and less than 0.5 mm for all linear measurements. No difference was observed between the two groups in any of the morphological variables of face or in the cervical lordosis angle (CVT/EVT). However, subjects in the study group showed significantly higher craniocervical angulations (SN/OPT, SN/CVT, SN/EVT, pns-ans/OPT, pns-ans/CVT, pns-ans/EVT, GoGn/OPT, GoGn/CVT, GoGn/EVT) compared with the control subjects (p<0.001). The subjects with ACL injury had significant head extension compared with the control subjects.     

SEMG activity of jaw‐closing muscles during biting with different unilateral occlusal supports

Summary The aim of this study was to test the hypothesis that experimental and reversible changes of occlusion affect the levels of surface electromyographic (SEMG) activity in the anterior temporalis and masseter areas during unilateral maximal voluntary biting (MVB) in centric and eccentric position. Changes were achieved by letting 21 healthy subjects bite with and without a cotton roll between the teeth. The placement alternated between sides and between premolar and molar areas. The SEMG activity level was lower when biting in eccentric position without than with a cotton roll between teeth (P < 0·043). It was always lower with premolar than with molar support when biting with a cotton roll (P < 0·013). In the anterior temporalis areas, the SEMG activity was always lower on the balancing than on the working side (P < 0·001). Such a difference was also found in the masseter areas but only during molar‐supported centric biting (P = 0·024). No differences were found when comparing the SEMG levels in masseter areas between centric and eccentric biting (P > 0·05). In the anterior temporalis area, the balancing side SEMG activity was lower in eccentric than in centric but only in molar‐supported biting (P = 0·026). These results support that the masseter and anterior temporalis muscles have different roles in keeping the mandible in balance during unilateral supported MVB. Changes in occlusal stability achieved by biting with versus without a cotton roll were found to affect the SEMG activity levels.     

Commentaries on scientific papers published in this edition

Abstract

Objectives: To investigate the interrelationships between factors involved in orthodontic treatment seeking by children aged 12–15?years.

Setting: State funded orthodontic clinic at the Faculty of Dentistry of the Rio de Janeiro State University (UERJ), Rio de Janeiro, Brazil, and a nearby public school.

Subjects and methods: One hundred and ninety‐four adolescents aged 12–15?years took part in the study; 92 had sought orthodontic treatment at UERJ (orthodontic group) and 102 were from a nearby public school and had never undergone or sought orthodontic treatment (comparison group). Each participant underwent a comprehensive oral examination, and both parent and child were questioned about who had initiated the orthodontic referral.

Outcomes: Normative need assessed with IOTN DHC; clinician and self‐perceived aesthetic perception assessed with IOTN AC, previous caries experience was determined using the decayed, missing and filled teeth index (DMFT) and WHO diagnostic criteria. The ‘Brazil Economic Classification Criteria’ was used to classify the socioeconomic status. Intra‐examiner repeatability and inter‐examiner agreement were assessed with kappa statistics. Univariate and multiple logistic regression analyses were used to investigate the association between orthodontic treatment seeking (dependent variable) and the independent variables (i.e. aesthetic impairment, malocclusion severity, socioeconomic status, gender, age and DMFT).

Results: Univariate analyses showed that self‐perceived aesthetics (P<0·001), examiner‐assessed aesthetics (P?=?0·01) and treatment need (P<0·001), socioeconomic status (P<0·001) were significantly associated with orthodontic treatment seeking, but gender (P?=?0·22) and DMFT (P?=?0·41) were not. Multiple logistic regression analyses showed that poor self‐perceived aesthetics (OR?=?16·7; 95% CI: 4·17–61·9), more severe malocclusion (OR?=?3·4; 95% CI 1·64–7·14) and better socioeconomic position (OR?=?39·1; 95% CI: 5·47–280·54) significantly influenced the decision to seek orthodontic treatment.

Conclusions: Concern about dental appearance and the desire for treatment, together with normative orthodontic need, should be carefully assessed by dentists before referring patients to specialized orthodontic care in publicly‐funded clinics. In a publicly‐funded oral health care system, self‐perceived orthodontic treatment need is the key to establishing treatment priority.     

Influence of oral stabilization appliances in intra-articular pressure of the temporomandibular joint

Aims:

This study analyzed the intra-articular pressure in the upper compartment of the temporomandibular joint (TMJ) under different functional conditions. The influence of stabilization appliances on intra-articular pressure was studied.

Methodology:

Seventy-four joints from 64 patients (55 women and 9 men; mean age: 43·2±11·86 years; range: 19–61 years) with TMJ disorders were examined. Only 50 joints passed the inclusion criteria. Intra-articular pressure was measured using a 21G needle inserted into the joint and connected to a pressure transducer. Pressure was measured with the jaw in the following positions: at rest, maximal mouth opening, clenching in maximal intercuspal position, and clenching with an oral interoclusal appliance.

Results:

Fifty joints were included in the study (without blood reflux), mean pressure at rest was negative (–6·06±4·55 mmHg); when the mouth was opened to its maximal position the pressure was lower (?26·09±6·42 mmHg). Mean intra-articular pressure was higher in the maximal intercuspal position (58·56±24·90 mmHg). When an interoclusal appliance device was fitted, mean intra-articular pressure reduced its value by 31·24%, which reached a mean value of 40·56±18·84 mmHg (P<0·001). There were no significant differences in sex. The group over 45 years old had higher pressure values in maximal open mouth position than the group of patients under 45 years old (P<0·02).

Conclusions:

Interoclusal appliances can reduce pressure in the upper compartment of the TMJ and improve functional status of the joint.     

The occlusal effects of digit sucking habits amongst school children in Northamptonshire (UK)

Abstract

Objective: To compare the occlusal characteristics of persistent digit suckers with those of a group of individuals who reported never to have sucked their thumb or finger.

Setting: School children and regular attenders to four general dental practices in Kettering, UK.

Design: Cross‐sectional, observational.

Outcome measures: Prevalence of anterior open bite, posterior crossbite, size of overjet, overbite and buccal segment relationship.

Subjects and methods: The exposed group consisted of 7–13‐year‐old children with a persistent digit sucking habit or those who had given up the habit less than 2?years previously, compared with an unexposed group of children who had never reported a history of the habit. Upper and lower alginate impressions were taken and the resultant study models were used to measure occlusal differences between the two groups.

Results: Following exclusions, 39 digit suckers were compared to 36 non‐suckers. The odds of a reduced overbite being present were significantly higher in the digit sucking group compared to the non‐suckers (OR: 5·6, 95% CI: 1·6–20·8). The prevalence of anterior open bites was higher in the digit suckers (P<0·001). Although the overjet was slightly increased in the digit suckers compared with the non‐suckers (mean difference: 1?mm, P?=?0·036), this result needs to be interpreted with caution. No significant differences were seen in the presence of posterior crossbites or buccal segment relationships between the two groups.

Conclusions: This study has shown that reduced overbite and anterior open bites were significantly more prevalent in digit suckers. The orthodontic management of anterior open bites can involve complex and prolonged treatment. Early intervention to eliminate digit sucking habits is therefore recommended on both oral health and health economic grounds.     

Effect of a rapid maxillary expansion on snoring and sleep in children: a pilot study

Aim:

The aim of this study was to assess the efficacy of the McNamara rapid palatal expansion device for the treatment of sleep disorders in children.

Methods:

The sample enrolled 12 children aged 4–11 years. Children with snoring and bruxism whose parents did not agree to tonsil surgery were included in the study. During the initial evaluation, a questionnaire addressing sleep was administered, and plaster models were made for the construction of the McNamara rapid maxillary expansion device. The expansion period was 7–15 days, and the McNamara device was removed after 6–8 months. The same questionnaire was administered again after 30 days of use of the orthopedic appliance. The data were analyzed using the McNemar test, with the level of significance set to 5% (P<0·05).

Results:

Significant improvements were found in tiredness upon waking (P?=?0·002), mood (P?=?0·008), lip seal (P?=?0·031), drooling during sleep (P?=?0·031), snoring (P?=?0·001), and bruxism (P?=?0·0062).

Conclusion:

The use of non-invasive methods, such as rapid maxillary expansion, can be an effective treatment for snoring and other undesirable sleep behaviors in children.