Ama Johal

Orthodontic measurements on digital study models compared with plaster models: a systematic review

The aim of this study is to evaluate the validity of the use of digital models to assess tooth size, arch length, irregularity index, arch width and crowding versus measurements generated on hand-held plaster models with digital callipers in patients with and without malocclusion. Studies comparing linear and angular measurements obtained on digital and standard plaster models were identified by searching multiple databases including MEDLINE, LILACS, BBO, ClinicalTrials.gov, the National Research Register and Pro-Quest Dissertation Abstracts and Thesis database, without restrictions relating to publication status or language of publication. Two authors were involved in study selection, quality assessment and the extraction of data. Items from the Quality Assessment of Studies of Diagnostic Accuracy included in Systematic Reviews checklist were used to assess the methodological quality of included studies. No meta-analysis was conducted. Comparisons between measurements of digital and plaster models made directly within studies were reported, and the difference between the (repeated) measurement means for digital and plaster models were considered as estimates. Seventeen relevant studies were included. Where reported, overall, the absolute mean differences between direct and indirect measurements on plaster and digital models were minor and clinically insignificant. Orthodontic measurements with digital models were comparable to those derived from plaster models. The use of digital models as an alternative to conventional measurement on plaster models may be recommended, although the evidence identified in this review is of variable quality.

Self-ligating brackets in orthodontics. A systematic review.

OBJECTIVE To evaluate the clinical differences in relation to the use of self-ligating brackets in orthodontics. MATERIALS AND METHODS Electronic databases were searched; no restrictions relating to publication status or language of publication were applied. Randomized controlled trials (RCTs) and controlled clinical trials (CCTs) investigating the influence of bracket type on alignment efficiency, subjective pain experience, bond failure rate, arch dimensional changes, rate of orthodontic space closure, periodontal outcomes, and root resorption were selected. Both authors were involved in study selection, validity assessment, and data extraction. Disagreements were resolved by discussion. RESULTS Six RCTs and 11 CCTs were identified. Meta-analysis of the influence of bracket type on subjective pain experience failed to demonstrate a significant advantage for either type of appliance. Statistical analysis of other outcomes was unfeasible because of inadequate methodological design and heterogenous designs. CONCLUSIONS At this stage there is insufficient high-quality evidence to support the use of self-ligating fixed orthodontic appliances over conventional appliance systems or vice versa.

The relationship between craniofacial anatomy and obstructive sleep apnoea: a case-controlled study.

The aim of the study was to identify craniofacial and pharyngeal anatomical factors directly related to obstructive sleep apnoea (OSA). The design and setting was a hospital‐based, case‐controlled study. Ninety‐nine subjects (78 males and 21 females) with a confirmed diagnosis of OSA, who were referred to the Dental Hospital for construction of a mandibular advancement splint were recruited. A similar number of control subjects, matched for age and sex, were recruited after completing snoring and Epworth Sleepiness Scale questionnaires to exclude habitual snoring and daytime sleepiness. An upright cephalogram was obtained and skeletal and soft tissue landmarks were traced and digitized. In OSA subjects the anteroposterior skeletal measurements, including maxillary and mandibular length were reduced (P < 0.001). The intermaxillary space was found to be 3.1 mm shorter in OSA subjects (P = 0.001). The nasopharyngeal airway in OSA subjects was narrower (P < 0.001) but pharyngeal length showed no difference. The tongue size was increased (P = 0.021), soft plate length, thickness and area were all greater (P < 0.001) and the hyoid bone was more inferiorly positioned in OSA subjects (P < 0.001). This study identifies a significant number of craniofacial and pharyngeal anatomical factors directly related to OSA.

Maxillary Morphology in Obstructive Sleep Apnea: A Cephalometric and Model Study

The relationship between maxillary constriction and the etiology of obstructive sleep apnea (OSA) is not clear. This prospective case-control study compared maxillary morphology in 94 dentate subjects (47 OSA and 47 control subjects), using upright lateral cephalograms and study models. Each subject had height, weight, and neck circumference measurements recorded and underwent an orthodontic examination. An upright lateral cephalogram and dental impressions were obtained. All data were analyzed using the SPSS statistical package applying nonparametric tests at the 5% level of significance. Male and female subjects were examined separately, and statistically significant differences were found between the cephalometric measurements for OSA and the control subjects. The palatal angle was more obtuse in male OSA subjects (P < .05). The PNS-posterior pharyngeal wall was shorter (P < .05) and the soft palate longer in female OSA subjects (P < .05). Minimum palatal airway widths were significantly reduced in both male (P < .01) and female (P < .001) subjects. In the comparison of study model measurements, palatal heights in OSA subjects were greater (P < .05). Thus, maxillary morphological differences do exist between OSA and control subjects, supporting their role as a etiological factor.

Sleep nasendoscopy as a predictor of treatment success in snorers using mandibular advancement splints.

This study assessed the effect on the upper airway during sleep nasendoscopy of mimicking the action of a mandibular advancement splint. Twenty-seven subjects with a diagnosis of sleep-disordered breathing were referred for mandibular advancement splint therapy following sleep nasendoscopy. Sleep nasendoscopy was repeated for all subjects with, and without, the appliance in situ. Follow-up sleep studies with a mandibular advancement splint in situ were undertaken for 19 individuals with significant obstructive sleep apnoea. With the mandibular advancement splint, subjective snoring levels and airway patency improved as predicted in all but one individual. Residual palatal flutter was predicted for five subjects and occurred in eight individuals. Follow-up sleep studies showed highly statistically significant reductions in median apnoea-hypopnoea index (from 28.1 to 6.1, p < 0.001). Mimicking the action of a mandibular advancement splint during sleep nasendoscopy helps considerably in the patient selection process for this form of treatment.

The effect of mandibular advancement appliances on awake upper airway and masticatory muscle activity in patients with obstructive sleep apnoea

Background:  There is little understanding of how dental appliances, designed to posture the mandible forwards, act on pharyngeal airway dilatory and masticatory muscles in patients with obstructive sleep apnoea (OSA). This study evaluates, in a prospective cohort design, the effect of mandibular advancement splints (MAS) on awake genioglossus (GG), geniohyoid (GH) and masseter (M) muscle activity.

Impact of sleep nasendoscopy on the outcome of mandibular advancement splint therapy in subjects with sleep-related breathing disorders

AIM To evaluate the impact of positive sleep nasendoscopy, with simultaneous mandibular advancement, on the outcome of mandibular advancement splint therapy in 120 subjects with sleep-related breathing disorders. METHODOLOGY Overnight polysomnography and sleep nasendoscopy were performed prior to splint therapy. Follow-up sleep studies, with the appliance in situ, were undertaken for those patients with obstructive sleep apnoea. Subjective outcome measures assessed daytime sleepiness and snoring. RESULTS One hundred and seven (89 per cent) subjects completed the study. Follow-up sleep studies confirmed the efficacy of treatment, with patients showing a mean reduction in apnoea/hypopnoea index (from 18.9 to 4.9, p<0.001), Epworth sleepiness scale scores (from 11 to seven, p<0.001) and partner-recorded snoring scores (from 14 to eight, p<0.001). CONCLUSION Sleep nasendoscopy, with concomitant mandibular advancement to mimic the treatment effect, could be of prognostic value in determining successful mandibular advancement splint therapy.

Near-end of treatment panoramic radiograph in the assessment of mesiodistal root angulation.

OBJECTIVES To test the hypothesis that there is no difference between the actual mesiodistal root angulation and the mesiodistal root angulation as measured on the panoramic radiograph. MATERIALS AND METHODS A typodont dentition was set up into a Class I occlusion. Wire struts were placed on the buccal surface of each tooth to represent their long axes. The dentition was fixed into a natural skull for imaging. The radiographic and true mesiodistal angulation of each tooth to a horizontal reference plane (the arch wire) was measured using a coordinate measuring machine (CMM). The mesiodistal root positions were then altered to a more mesial and then more distal position and the measurements were repeated. RESULTS Only 26.7% of the radiographic root angulations were within the clinically acceptable angular variation range of +/-2.5 degrees . The greatest variation in the upper arch occurred in the canine-premolar area where the roots were projected as being more divergent. The greatest variation in the lower arch occurred in the lateral incisor-canine region where these roots were projected as being more convergent. The extent of radiographic distortion is statistically greater in the lower arch than in the upper arch in the ideal (P < or = .05) and distal (P < or = .01) root positions. CONCLUSIONS The hypothesis is rejected. There is a clinically significant variation between the radiographic and the true root angulations recorded. Caution is advised when interpreting mesiodistal root angulation using this radiograph.

State of the science on controversial topics: orthodontic therapy and gingival recession (a report of the Angle Society of Europe 2013 meeting)

BackgroundControversy exists in the literature between the role of orthodontic treatment and gingival recession. Whilst movement of teeth outside the alveolar bone has been reported as a risk factor for gingival recession, others have found no such association.FindingsThe Angle Society of Europe devoted a study day to explore the evidence surrounding these controversies. The aim of the day was for a panel of experts to evaluate the current evidence base in relation to either the beneficial or detrimental effects of orthodontic treatment on the gingival tissue.ConclusionsThere remains a relatively weak evidence base for the role of orthodontic treatment and gingival recession and thus a need to undertake a risk assessment and appropriate consent prior to the commencement of treatment. In further prospective, well designed trials are needed.

The impact of orthodontic treatment on quality of life and self-esteem in adult patients.

OBJECTIVES To assess the impact of fixed orthodontic treatment on oral health related quality of life (OHRQoL) and self-esteem in adults. SUBJECTS AND METHODS A prospective study design was applied, within private practice. Sample size estimation revealed a minimum of 52 subjects, allowing for drop outs. All participants completed a set of validated questionnaires at baseline (T0), 1- (T1), 3- (T2), and 6-months (T3) and post-treatment (T4). These included the Rosenberg Self-esteem scale, the Oral Health Impact Profile (OHIP-14) and a socioeconomic status questionnaire. The Dental Health Component of the Index of Orthodontic Treatment Need (IOTN) was used to assess malocclusion severity. RESULTS Sixty-one subjects were recruited, with only one subject lost to follow-up. A statistically significant difference in OHRQoL scores was seen between: T0 and T1 (P = 0.001); T0 and T2 (P = 0.020). There was no statistical difference between T0 and T3 (P = 0.078) or T4 (P = 0.565), where OHRQoL improved to pre-treatment scores. A significant difference in self-esteem scores was observed between baseline and end of treatment (P = 0.002). CONCLUSIONS Undergoing fixed orthodontic therapy had a negative impact on the overall OHRQoL, during the first 3 months of treatment, which then improved to pre-treatment scores, whilst a significant increase was observed in self-esteem as a result of treatment.