Impacts of mandibular setback with or without maxillary advancement for class III skeletal correction on sleep-related respiratory parameters: A systematic review and meta-analysis.

A systematic review and meta-analysis was conducted to evaluate the impacts of mandibular setback with or without maxillary advancement for class III skeletal correction on respiratory parameters measured by polysomnography (PSG) and to compare these respiratory parameters between these procedures for class III skeletal correction. Six electronic databases were searched up to June 2023. Studies comparing PSG parameters before and after orthognathic surgery for skeletal class III patients were selected for further analysis. The outcomes of interest were apnoea-hypopnea index (AHI), respiratory disturbance index (RDI), the lowest oxygen saturation (lowest SpO2), the average oxygen saturation (mean SpO2), and the 3% oxygen desaturation index (3% ODI). Data extraction, methodological quality assessment, risk of bias assessment, meta-analysis, and subgroup analysis were performed. Sixteen studies with a total of 476 patients who underwent orthognathic surgery for class III skeletal correction were included for meta-analysis. The risk of bias level was moderate for most studies. All PSG parameters before and after orthognathic surgery were not significantly different. The different surgical procedures also did not significantly affect post-operative PSG parameters. 5.8% of patients developed post-operative obstructive sleep apnoea (OSA). Most of them underwent a large distance of mandibular setback. There is a moderate level of evidence that mandibular setback with or without maxillary advancement for class III skeletal correction does not pre-dispose young and healthy patients to obstructive sleep apnoea when evaluated in the short term after surgery. However, post-operatively developed OSA was found in several isolated cases that underwent a large amount of mandibular setback with or without maxillary advancement.

A Comparison of Tooth Size and Arch Dimensions Among Measurements Taken Intraorally with 3D-Printed and Digital Models Obtained from Intraoral Scans.

Background: To compare measurements of tooth size and arch dimensions among those taken directly intraorally with those made on digital and 3D printed models produced by intraoral scanning. Material and Methods: Sixty-six participants were recruited. Intraoral tooth size and arch measurements were taken intraorally with a digital caliper. Digital impressions were taken with an iTero® intraoral scanner. The three-dimensional digital models were measured using a 3D diagnostics tool (OrthoCAD software). The same digital models were used to fabricate physical models using a resin 3D printer (Elegoo Saturn). The measurements were repeated on 3D printed models by using the digital caliper. The recorded parameters included mesiodistal tooth widths, transverse, and antero-posterior dimensions. All measurements were repeated to assess intra- and inter- examiner reliability. The validity of each measurement method was assessed by repeated measures ANOVA with post-hoc pairwise comparisons (p<0.5). Results: The mean differences among three methods for all parameters were statistically significant (p<.05) but were considered to be clinically insignificant, except for the upper intercanine width. Direct intraoral measurements tend to be smaller than the digital and 3D printed models. The ICCs values indicated excellent intra- and inter-examiner reliability which demonstrates high reproducibility for all measurements on all model types. Conclusions: Direct intraoral measurements tend to be smaller than the digital and 3D printed models. However, the accuracy of measurements made directly intraorally, and on digital and 3D models from intraoral scans is clinically acceptable, except for the upper intercanine width. Key words:Tooth measurements, Accuracy, Dental models, 3D printing, Digital model.

Influence of functional and esthetic expectations on orthodontic pain.

OBJECTIVES: To investigate the effect of orthodontic treatment outcome (OTO) expectations on the level of pain intensity experienced after orthodontic elastomeric separation (OES). MATERIALS AND METHODS: A total of 100 orthodontic patients (74 female and 26 male, age 14 years and above) from the Faculty of Dentistry, Mahidol University were enrolled. Before OES, questionnaires were administered to obtain patients' expectations regarding various aspects of OTO as well as OES pain expectations. Real-time self-reported pain intensity from OES at the maxillary and mandibular first permanent molars was obtained before and immediately after separator placement and at 6 h, 24 h, and then every day until day 7 after OES. Data were analyzed for the relationship between OTO expectations and OES pain intensity. The level of significance was set at 0.05. RESULTS: The maximum OES pain intensity occurred on day 2 after OES and gradually decreased to the pretreatment level on day 7. The degree of facial, tooth alignment, masticatory function improvement expectations, and a high level of OES pain expectations were significantly associated with the severity of OES pain after separator placement. CONCLUSION: Esthetic and functional expectations of OTO were significantly associated with OES pain intensity. Thus, knowledge about esthetic and functional expectations may help to predict patient's pain response to orthodontic treatment.

The Protocol of Low-level Laser Therapy in Orthodontic Practice: A Scoping Review of Literature.

Low-level laser therapy (LLLT) has been widely investigated as an adjunct technique for orthodontic treatment due to photobiomodulation effect. LLLT appears to be supportive for an orthodontic practice in terms of tooth movement acceleration, pain relief, and root resorption management. The decrease in these adverse effects will enhance the compliance in orthodontic patients, which could positively impact treatment outcomes. However, there seemed to be inconsistency in the impact of LLLT as well as its laser and treatment parameters. This scoping review aimed to evaluate the impact of different irradiation parameters on tooth movement acceleration, pain relief, and root resorption as well as to construct a protocol of LLLT in orthodontic practice. The search was conducted across PubMed, Scopus, Web of Science, Embase, Google Scholar, and the reference lists of identified articles. The last search was conducted on October 10, 2021 to identify experiments in humans regarding the application of LLLT as noninvasive treatment in orthodontic practice published between 2010 and 2021. However, they were excluded if they were not clinical research, if they did not report the source of laser, or if they were not relevant to tooth movement, pain perception, and root resorption, or if they were not available in English or in full-text. Following the systematic search and selection process, 60 articles were included in this review. A majority of included articles were published in the past few years. The findings of this review supported the application of LLLT in orthodontic practice with purposes of tooth movement acceleration and pain reduction. The positive impact of LLLT on root resorption had not been clearly evident yet. As this review demonstrated heterogeneity of both laser and treatment parameters, further research should be required to ensure the effectiveness of its specific parameters in orthodontic practice.

Accuracy of Tooth Movement with In-House Clear Aligners.

AIM: To evaluate accuracy of tooth movements with in-house clear aligners. METHODS: This prospective clinical study included 30 participants for anterior clear aligners with crowding not exceeding 4 mm. per arch, non-extraction cases with no changes in posterior relationship. Aligners were created with OrthoAnalyzerTM software, attachments were placed as needed and IPR was performed in required areas. The final stage of tooth movement was compared with predicted tooth movement by superimposition of the two STL models. Maxillary arch was superimposed on stable posterior teeth and best fit on palatal rugae while mandibular arch was superimposed on unmoved posterior teeth. The amount of differences in predicted and achieved tooth movements were compared. Six types of tooth movement were included in the comparison which were labial, lingual, mesiodistal, intrusion, extrusion and rotation. RESULTS: Total sample consisted of 259 anterior teeth (126 maxillary, 133 mandibular). The achieved tooth movements were significantly lesser than the predicted tooth movements in all the six types of tooth movement. Overall accuracy of tooth movement with clear aligner was 56.18%. The most accurate tooth movement was mesiodistal (72.33%). The least accurate movement was intrusion (43.28%). While mesiodistal, labial, rotation and lingual tooth movements were more predictable than intrusion and extrusion. CONCLUSION: Understanding the accuracy of different tooth movements might help in case selection, treatment plan and development or increase accuracy and predictability of in-house clear aligners.