Biomechanics of conventional and miniscrew-assisted rapid palatal expansion.

Posterior Crossbite is a common condition resulting because of transverse maxillary deficiency. The growth of the craniofacial complex finishes first in the transverse dimension, followed by sagittal and vertical dimensions. Conventional rapid palatal expansion (RPE) appliances are commonly used to correct transverse maxillary deficiency. Although RPE is efficient in correcting posterior crossbite, it results in dental side effects such as buccal tipping of maxillary molars, root resorption, bone dehiscence, and relapse. Mini-implant-assisted RPE has been introduced to increase the skeletal effects of expansion especially in patients with increased maturation and greater interdigitation of midpalatal suture. This article will review the biomechanics of RPE and mini-implant-assisted RPE. Additionally, the different designs of MARPE and the long-term clinical effects of expansion appliances will also be discussed in detail.

Mandibular molar protraction: A comparison between fixed functional appliances and temporary anchorage devices.

INTRODUCTION: This study aimed to compare the efficiency of temporary anchorage devices (TADs) and fixed functional appliances (FFAs) for mandibular molar protraction. METHODS: Orthodontic records of 1050 consecutively treated patients with molar protraction were screened. Thirty-six records (22 females and 14 males; mean age, 17.4 years) were divided into two groups: TAD (21 subjects with 25 edentulous spaces) and FFA (15 subjects with 24 edentulous spaces). The primary outcome measure was the efficiency of protraction [magnitude and time required for protraction (rate) and anchor loss (AL)]. The secondary outcomes involved measuring the type of tooth movement (TOTM), external apical root resorption (EARR), alveolar bone height change (ABHC), alveolar bone width change (ABWC) and appliance failure. RESULTS: The rate of tooth movement was significantly higher for FFAs (0.83 ± 0.35 mm/month) versus TADs (0.49 ± 0.2 mm/month) (P = .005). Total treatment duration was less for FFAs (34.78 ± 8.1 months) versus TADs (47.72 ± 13.94 months) (P = .002). TOTM was similar for both (P = .909). EARR was 1.42 ± 1.38 mm for TAD and 1.25 ± 0.88 mm for FFA (P = .81). ABHC increased in the FFA group (1.01 ± 3.62 mm) and decreased for the TAD group (0.68 ± 1.66 mm). ABWC increased for both TAD (1.81 ± 1.73 mm) and FFA (1.75 ± 1.35 mm). The failure rate was 50% for FFAs and 33% for TADs. CONCLUSIONS: Both systems provided translation of lower molars with comparable anchorage control. However, FFAs were more efficient than TADs for lower molar protraction.

Content analysis of AI-generated (ChatGPT) responses concerning orthodontic clear aligners.

OBJECTIVES: To assess the accuracy of ChatGPT answers concerning orthodontic clear aligners. MATERIALS AND METHODS: A cross-sectional content analysis of ChatGPT generated responses to queries related to clear aligner treatment (CAT) was undertaken. A total of 111 questions were generated by three orthodontists based on a set of predefined domains and subdomains. The artificial intelligence (AI)-generated (ChatGPT) answers were extracted and their accuracy was determined independently by five orthodontists. The accuracy of answers was assessed using a prepiloted four-point scale scoring rubric. Descriptive statistics were performed. RESULTS: The total mean accuracy score for the entire set was 2.6 ± 1.1. It was noted that 58% of the AI-generated answers were scored as objectively true, 18% were selected facts, 9% were minimal facts, and 15% were false. False claims included the ability of CAT to reduce the need for orthognathic surgery (4.0 ± 0.0), improve airway function (3.8 ± 0.5), achieve root parallelism (3.6 ± 0.5), alleviate sleep apnea (3.8 ± 0.5), and produce more stable results compared to fixed appliances (3.8 ± 0.5). CONCLUSIONS: The overall level of accuracy of ChatGPT responses to questions concerning CAT was suboptimal and lacked citations to relevant literature. Ability of the software to offer current and precise information was limited. Therefore, clinicians and patients must be mindful of false claims and relevant facts omitted in the answers generated by ChatGPT.

Assessment of clear aligner accuracy of 2 clear aligners systems.

INTRODUCTION: This study compared treatment efficacy for specific tooth movements between 2 clear aligner systems (Clarity [3M Oral Care Solutions, St Paul, Minn] and Invisalign [Align Technology, San Jose, Calif]). METHODS: The study sample included 47 patients (7 males, 40 females; mean age, 36.57 ± 15.97 years) treated with Invisalign and 37 (4 males, 33 females; mean age, 34.30 ± 16.35 years) treated with Clarity aligners who completed their first set of aligners and had an initial refinement scan. Initial and predicted models were obtained from the initial simulated treatment plan. The first model of the refinement scan was labeled as achieved. SlicerCMF software (version 3.1; http://www.slicer.org) was used to superimpose the achieved and predicted digital models over the initial ones with regional superimposition on the relatively stable first molars. Nine hundred forty teeth in the Invisalign system were measured for horizontal, vertical, and angular movements and transverse width and compared with similar measurements of 740 teeth for the Clarity aligners. The deviation from the predicted was calculated and compared between both systems. RESULTS: The deviation achieved from the predicted was significant between the groups for the mandibular interpremolar and intercanine widths (P <0.05). Clarity aligners significantly undercorrected rotations compared with Invisalign for the mandibular first premolars, mandibular canines, maxillary canines, and maxillary central incisors. There was no statistically significant difference between the groups for the achieved vs predicted movements in the horizontal and vertical planes (P >0.05). CONCLUSIONS: The efficacy of clear aligner therapy systems (Clarity and Invisalign) in treating mild and moderate malocclusions was comparable. Deviation of the achieved movements from the predicted was greatest for rotational and vertical movements.

Insight into clear aligner therapy protocols and preferences among members of the American Association of Orthodontists in the United States and Canada.

OBJECTIVES: To investigate aligner treatment protocols among orthodontists in the United States and Canada and assess the factors influencing clinician choices in aligner systems, treatment protocols, and targeted malocclusions for aligners. MATERIALS AND METHODS: A validated online questionnaire was developed specifically for this research and consisted of three sections. Section 1 evaluated demographics and experience with aligners. Section 2 assessed patient selection and demands and clinician confidence in treating various malocclusions with aligners. Section 3 evaluated treatment protocols used by clinicians. The American Association of Orthodontists Partners in Research Program distributed the survey via e-mail to active members in the United States and Canada. RESULTS: A total of 160 providers completed the survey. Aligners were used by 65.00% of respondents, with the Invisalign system the most popular (81.25%). Aligners were mostly used for adults (97.50%). Tipping was ranked as the easiest movement (1.79 ± 1.35). Extrusion (4.34 ± 1.53) and root movement (4.31 ± 1.27) were ranked as the most difficult. Most were confident treating mild (98.8%) and moderate (82.5%) crowded cases, spacing (96.9%), and anterior crossbite (85%). Of the providers, 58.12% recommended aligners to be changed weekly. Respondents who were confident addressing some of the severe malocclusions were more likely to use Invisalign. CONCLUSIONS: Invisalign is the most popular aligner system, and clinicians seem to be confident using it. Providers are aware of the pitfalls of aligners; they find it challenging to perform root movement and extrusion, and they seem confident treating mild to moderate malocclusions. They avoid complex cases with impactions and severe skeletal problems.

The accuracy of artificial intelligence-based virtual assistants in responding to routinely asked questions about orthodontics.

OBJECTIVES: To evaluate the utility and efficiency of four voice-activated, artificial intelligence-based virtual assistants (Alexa, Google Assistant, Siri, and Cortana) in addressing commonly asked patient questions in orthodontic offices. MATERIALS AND METHODS: Two orthodontists, an orthodontic resident, an oral and maxillofacial radiologist, and a dental student used a standardized list of 12 questions to query and evaluate the four most common commercial virtual assistant devices. A modified Likert scale was used to evaluate their performance. RESULTS: Google Assistant had the lowest (best) mean score, followed by Siri, Alexa, and Cortana. The score of Google Assistant was significantly lower than Alexa and Cortana. There was significant variablity in virtual assistant response scores among the evaluators, with the exception of Amazon Alexa. Lower scores indicated superior efficiency and utility. CONCLUSIONS: The common commercially available virtual assistants tested in this study showed significant differences in how they responded to users. There were also significant differences in their performance when responding to common orthodontic queries. An intelligent virtual assistant with evidence-based responses specifically curated for orthodontics may be a good solution to address this issue. The investigators in this study agreed that such a device would provide value to patients and clinicians.

Estimating the 3-D location of impacted maxillary canines: A CBCT-based analysis of severity of impaction.

OBJECTIVES: The objective of the study was to quantify the 3-D location of impacted canines by measuring their linear and angular deviations in relation to adjacent structures and further evaluate impaction severity. METHODS: CBCT images of 314 impacted canines were analysed in the sagittal, coronal and axial planes. Linear and angular measurements were recorded. Canine inclination was identified in coronal and sagittal planes. An evaluation system was constructed for analysis. Upright canine was considered as the appropriate position for fully erupted maxillary canine. Outcomes were compared between right and left sides and by gender. For categorical variables, chi-square tests were used while Mann-Whitney U test was used for continuous variables. Regression models were used to measure severity. RESULTS: Impactions were greater in females (119/207; 57.5%). No significant differences between unilateral (100/207; 49.3%) and bilateral (107/207; 51.7%) (P > 0.05). Out of 314 impactions, 105 (33.4%) were mild, 118 (37.58%) moderate and 91 (28.98%) severe. Severe impactions were primarily buccal (44/ 91; 48.3%), in the occlusal ½ of the adjacent incisor root (38/ 91, 41.7%), mesial to the distal border of central incisor (47/91, 51.6%), with sagittal angle value + >45 ̊ (46/ 91, 50.5%) and mesial tip + >30 ̊ (86/ 91, 94.5%). CONCLUSIONS: Severely impacted canines had their crowns buccal, closer to occlusal plane and mesial to the distal border of the central incisor with greater than 45-degree buccal inclination and greater than 30-degree mesial tip. The sagittal angle can have a significant impact on the severity of impaction. A new classification system was proposed to quantify severity.

Survival and failure rate of lower lingual bonded retainers: A retrospective cohort evaluation.

OBJECTIVE: The objectives of the study were to evaluate the survival rates for lower lingual retainers (LLRs) and to establish a correlation between patients' treatment-related factors (age, sex, malocclusion, appliance used for treatment, teeth bonded, retention protocols) to the survival of LLRs. MATERIALS AND METHODS: A total of 765 subjects [474 females and 291 males: mean age = 24.29 ± 10.67 years] between 2013 and 2022 were included. A customized data collection form was utilized to gather the data from the electronic health record (EHR) of subjects. Patient-related factors, crowding or spacing, deep bite or open bite and duration of treatment were extracted from patients' files. Kaplan-Meier estimator was used for the survival function, whereas Cox proportional hazards regression models were used to associate risk factors with retainer survival. RESULTS: 328 (42.9%) subjects had their LLRs failed, and the survival period was on average 17.37 ± 22.85 months. On the other hand, the follow-up period for the retainers that did not fail was on average 47.19 ± 23.66 months. 192 (28.3%) subjects had segment failure (retainer detached from 3 teeth or less), while 51 (7.5%) subjects had failures in more than 3 teeth (complete). None of the evaluated clinical variables were significantly associated with LLRs failure except for the bite category (P = .013) and the appliance used for treatment (P < .001). CONCLUSION: Success rate for LLRs was 57.1% over 47.19 months, failure rate was 42.9% over 17.37 months. The presence of deep bite and treatment with aligners were significantly associated with increased failure rate.

Learning Cephalometric Landmarks for Diagnostic Features Using Regression Trees.

Lateral cephalograms provide important information regarding dental, skeletal, and soft-tissue parameters that are critical for orthodontic diagnosis and treatment planning. Several machine learning methods have previously been used for the automated localization of diagnostically relevant landmarks on lateral cephalograms. In this study, we applied an ensemble of regression trees to solve this problem. We found that despite the limited size of manually labeled images, we can improve the performance of landmark detection by augmenting the training set using a battery of simple image transforms. We further demonstrated the calculation of second-order features encoding the relative locations of landmarks, which are diagnostically more important than individual landmarks.

Long-term effects on alveolar bone with bone-anchored and tooth-anchored rapid palatal expansion.

INTRODUCTION: The purpose of this study was to evaluate the long-term effects of bone-anchored and tooth-anchored expansion appliances on alveolar bone in vertical and horizontal dimensions, compared with controls, using cone-beam computed tomography. METHODS: We evaluated 180 cone-beam computed tomography scans for 60 patients at 3-time points: T1 (pretreatment), T2 (postexpansion), and T3 (posttreatment), for 3 groups: bone-anchored expansion appliance (BA), tooth-anchored expansion appliance (TA), and controls (T1-T3: BA, 2 years 8 months; TA, 2 years 9 months; control: 2 years 7 months). The intermolar width, molar angulation, palatal width, vertical buccal bone height, buccal bone thickness at the alveolar crest, and root apex were measured in the 3 groups at different time points. RESULTS: In the short term, both BA and TA led to a statistically significant increase in the intermolar width and vertical buccal bone loss after expansion compared with controls. Vertical buccal bone loss was significantly greater in TA than in BA. In addition, TA led to significantly increased molar angulation (buccal tipping) compared with controls at T2. There were no significant differences in the 3 groups in the long term except vertical buccal bone loss, which was significantly greater in TA than controls. A substantial correlation was found between molar angulation and vertical buccal bone loss, and a moderate negative correlation was found between intermolar width and buccal bone thickness at the alveolar crest at T3. CONCLUSIONS: There was no difference in the treatment outcomes between the 3 groups in the long term except vertical buccal bone loss, which was significantly increased in the TA group compared with controls.

Variability associated with mandibular ramus area thickness and depth in subjects with different growth patterns, gender, and growth status.

INTRODUCTION: The purpose of this study was to quantitatively evaluate the ramus bone parameters (ramus thickness and ramus depth) for miniscrew placement. An additional aim was to compare and contrast the ramus bone parameters in growing and nongrowing male and female subjects with hyperdivergent, normodivergent, hypodivergent facial types. METHODS: Cone-beam computed tomography scans of 690 subjects were evaluated. They were classified in terms of growth status, gender, and facial type. Ramus thickness was measured as the distance from the outer (buccal) to the inner (lingual) aspects of the mandibular ramus. Ramus depth was measured as the distance from the anterior border of the ramus to the inferior alveolar nerve canal. The measurements for ramus thickness and ramus depth were performed at 3 different levels bilaterally: (1) occlusal plane (OP), (2) 5 mm above the occlusal plane (5OP), and (3) 10 mm above the occlusal plane (10OP). RESULTS: Males showed a significantly higher ramus thickness than females (P <0.05). Ramus thickness decreased significantly (P <0.05) as we moved superior from the level of OP to 5OP and 10OP in all 3 facial types in both females (growing and nongrowing) and males (growing and nongrowing). Growing females and growing males had significantly higher ramus thickness than nongrowing females and nongrowing males, respectively. Ramus depth increased as we moved higher from the OP to 10OP. Hyperdivergent facial type showed a significantly reduced ramus depth compared with hypodivergent and normodivergent facial type in growing and nongrowing males and females at all 3 locations, namely OP, 5OP, and 10OP (P <0.05). CONCLUSIONS: Because of adequate ramus depth and ramus thickness, 5OP was considered the optimal insertion site for the placement of miniscrews. Patients with a hyperdivergent facial type showed significantly reduced ramus depth than hypodivergent and normodivergent facial types. Ramus thickness in males was significantly higher than in females in all facial types.

Long-term effects of conventional and miniscrew-assisted rapid palatal expansion on root resorption.

INTRODUCTION: The purpose of this study was to use cone-beam computed tomography to compare immediate and long-term effects of conventional and miniscrew-assisted rapid palatal expansion (MARPE) appliances on root resorption in 2 treatment groups and a control group. METHODS: One hundred eighty cone-beam computed tomography images of 60 patients at 3 time points were assessed: initial, postexpansion, and debond. The patients were divided into 3 groups: control (n = 19), rapid palatal expansion (RPE) appliance (n = 21), and MARPE (n = 20). The period of initial to debond varied for the 3 groups: 2 years, 7 months for controls; 2 years, 9 months for RPE; and 2 years, 8 months for MARPE. The length of mesiobuccal, distobuccal, and palatal root of the maxillary first molar (1M); the buccal root of maxillary first premolar; and second premolar were measured. The inclination of the 1M, intercuspal width (ICW), interroot width (IRW), ICW/IRW ratio, maxillary skeletal width were measured in all 3 groups at different time points. RESULTS: Immediately after expansion, RPE and MARPE groups showed a significant increase in the molar inclination, ICW, ICW/IRW ratio, and maxillary skeletal width compared with controls at postexpansion. However, the long-term comparison did not show any significant difference for root resorption and expansion parameters between the 3 groups, except the ICW/IRW ratio, which was higher in MARPE than controls at debond. A significant negative association was observed between the length of the mesiobuccal root of 1M and molar inclination (ß = -0.025; 95% confidence interval, -0.050 to 0.0008; P <0.05). The expansion of ICW and IRW did not show a significant association with root resorption. CONCLUSIONS: The long-term outcomes showed no difference in the amount of root resorption between the RPE, MARPE, and control groups. Molar inclination showed a significant negative association with the length of the mesiobuccal root of the 1M.

Biomechanics of clear aligners: hidden truths & first principles.

Over the past two decades clear aligner-based treatment has received remarkableattention from the orthodontic profession and more so from general practitioners.Different companies have emerged using vigorous advertisement to promote theirproducts mainly to patients and clinicians through social media. A variety of concepts,methods, and adjuncts have been introduced to enhance the efficacy andeffectiveness of clear aligners. However, the accuracy of tooth movement (vspredicted) with aligners still hovers around 50%. Fixed appliances fare much better onaccuracy and predictability of treatment. Why is there a discrepancy betweenexpected and actual outcomes? This paper utilizes 'first principles' and the existingevidence to unravel some of the key drawbacks of aligner-based therapy. Severalshortcomings in the biomechanical properties of aligner material (thermoplastics) thataffect clinical performance are discussed. Based on the first principles of alignerbiomechanics, this paper provides clinical insights for improving predictability and effectiveness of aligner therapy.

Intermaxillary elastics on skeletal anchorage and MARPE to treat a class III maxillary retrognathic open bite adolescent: A case report.

Class III malocclusion when accompanied with transverse and vertical maxillomandibular discrepancies such as posterior crossbite and vertical open bite leads to complicated orthodontic treatment. Proper diagnosis and treatment planning are important in such patients for a successful orthodontic outcome. A common treatment approach for patients with class III malocclusion is to wait for the completion of growth and plan orthognathic surgery in conjunction with orthodontic treatment. However, performing no treatment and waiting for growth to be completed during teen years could lead to negative effects on the patient's self-esteem. In such cases, a non-surgical option with skeletal anchorage could be used to correct the malocclusion without surgical intervention. This case report shows that in patients with severe class III malocclusion, skeletal anchorage can be used for the correction of anterior crossbite with intermaxillary elastics.

Bone-anchored versus tooth-anchored expansion appliances: Long-term effects on the condyle-fossa relationship.

BACKGROUND: The objective of this study was to evaluate the short-term and long-term effects of tooth-anchored and bone-anchored maxillary expansion appliances on the condyle-fossa relationship, compared to those in a matched control group. Another objective of the study was to evaluate whether the amount of dental and skeletal expansion is correlated with the condyle-fossa relationship. METHODS: A total of 180 cone-beam computed tomography scans (CBCTs) for 60 subjects were analyzed for 3 groups: 1) bone-anchored maxillary expansion (BA; n = 20); 2) tooth-anchored maxillary expansion (TA; n = 21); and 3) controls (n = 19) at pretreatment, post-expansion (T2), and post-treatment (T3). The posterior joint space (PJS), superior joint space (SJS), anterior joint space, angle of mandibular condyle, distance of the condyle to the mid-sagittal plane, the inter-molar cuspal width, and the skeletal maxillary width (SMW) were measured for all 3 groups. RESULTS: Both BA and TA led to a significant increase in inter-molar cuspal width, SMW, and TA led to a significant increase in PJS as compared to controls at T2. However, there was no significant difference in the joint spaces between the BA, TA, and control groups in the long term. Both the BA and TA groups showed a significant increase in SMW at T3 compared to the control group. Molar extrusion showed a weak correlation with PJS at T2 (r = 0.46) and T3 (r = 0.51), and a moderate correlation with SJS at T2 (r = 0.61) and T3 (r = 0.69). CONCLUSIONS: TA led to a significant increase in PJS, compared to a control group, at T2, but there was no long-term difference in the condyle-fossa relationship among the BA, TA, and control groups. Molar extrusion showed moderate correlation with SJS and PJS.

Where is the center of resistance of a maxillary first molar? A 3-dimensional finite element analysis.

INTRODUCTION: The center of resistance (CRes) is regarded as the fundamental reference point for predictable tooth movement. Accurate estimation can greatly enhance the efficiency of orthodontic tooth movement. Only a handful of studies have evaluated the CRes of a maxillary first molar; however, most had a low sample size (in single digits), used idealized models, or involved 2-dimensional analysis. The objectives of this study were to: (1) determine the 3-dimensional (3D) location of the CRes of maxillary first molars, (2) evaluate its variability in a large sample, and (3) investigate the effects of applying orthodontic load from 2 directions on the location of the CRes. METHODS: Cone-beam computed tomography scans of 50 maxillary molars from 25 patients (mean age, 20.8 ± 8.7 years) were used. The cone-beam computed tomography volume images were manipulated to extract 3D biological structures via segmentation. The segmented structures were cleaned and converted into virtual mesh models made of tetrahedral triangles having a maximum edge length of 1 mm. The block, which included the molars and periodontal ligament, consisted of a mean of 7753 ± 2748 nodes and 38,355 ± 14,910 tetrahedral elements. Specialized software was used to preprocess the models to create an assembly and assign material properties, interaction conditions, boundary conditions, and load applications. Specific loads were applied, and custom-designed algorithms were used to analyze the stress and strain to locate the CRes. The CRes was measured in relation to the geometric center of the buccal surface of the molar and the trifurcation of the molar roots. RESULTS: The average location of the CRes for the maxillary first molar was 4.94 ± 1.39 mm lingual, 2.54 ± 2.7 mm distal, and 7.86 ± 1.66 mm gingival relative to the geometric center of the buccal surface of the molar and 0.136 ± 1.51 mm lingual (P <0.01), 1.48 ± 2.26 mm distal (P <0.01), and 0.188 ± 1.75 mm gingival (P >0.01) relative to the trifurcation of the molar roots. In the anteroposterior (y-axis) and the vertical (z-axis) planes, the CRes showed significant association with root divergence (P <0.01). CONCLUSIONS: The CRes of the maxillary first molar was located apical and distal to the trifurcation area. It showed significant variation in its location. The 3D location of and also varied with the force direction. In some samples, this deviation was large. For accurate and predictable movement, tooth-specific CRes need to be calculated.

Survival estimates and risk factors for failure of palatal and buccal mini-implants.

OBJECTIVES: The primary objective was to compare the success and survival rates of palatal and buccal mini-implants for different locations and treatment requirements. The secondary objective was to evaluate risk factors influencing the survival of mini-implants. MATERIALS AND METHODS: In this retrospective cohort, records of 127 orthodontic patients with 257 mini-implants were included after imposing inclusion/exclusion criteria. Along with the implant failure data, factors such as age, sex, transverse location, anteroposterior location, and purpose of mini-implants were recorded. Kaplan-Meier survival analysis was used to draw the curves and a Nathan Mantel-David Cox test to compare variables. RESULTS: The failure rate of palatal mini-implants was 8.5%, whereas the failure rate for buccal shelf mini-implants was 68.7% (P < .0001). A significant difference was that the survival rates of palatal mini-implants were dependent on the purpose of the mini-implants and, for the buccal mini-implants, they were dependent on the skeletal malocclusion and location type of mini-implants (P < .05). CONCLUSIONS: The overall survival rate of palatal mini-implants was high, at 91.5%. Of the buccal mini-implants, inter-radicular mini-implants had the highest survival rate for 12 (75.5%) and 24 (71.9%) months, while buccal shelf mini-implants had the lowest success and survival rates for 12 (31.3%) and 24 (20.8%) months. Class III malocclusion had the lowest survival rate for the buccal mini-implants (65.3% and 54.2%) for 12 and 24 months.

Does Mini Screw Assisted Rapid Palatal Expansion (MARPE) have an influence on airway and breathing in middle-aged children and adolescents? A systematic review.

OBJECTIVE: This systematic review assessed the effects of tooth-borne (TB), tooth-bone-borne (TBB) and bone-borne (BB) micro-implant assisted rapid maxillary expansion (RPE) on airway dimensions and function in young children and adolescents (10- to 17-years-old). MATERIALS AND METHODS: Unrestricted search in 5 electronic databases until June 6th, 2020 was undertaken. This was supplemented with search in 6 additional resources for published, unpublished and ongoing trials up. Randomized (RCT) and non-randomized (Non-RCT) prospective studies that assessed the influence of the mini-screw-assisted rapid palatal expansion (MARPE) approach on airway and breathing in young children and adolescents were included. Two reviewers performed the study selection and data extraction blindly and in duplicate by two authors while disagreements. A random-effects model with a 95% confidence interval (CI), I2 and Chi2 tests were done. ROBINS-I, Cochrane Risk of Bias and GRADE tools were used. Reporting of this review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULTS: Overall, 518 articles were retrieved; only 3 studies (2 RCT and one non-RCT) met the inclusion criteria. Both TB RPE and BB RPE improved on a short-term basis the dimensions of the airway, though the difference was not significant (P>0.05). TBB RPE significantly improved nasal airflow [(Mean difference (MD) 52.7 cm3/s, 95% confidence interval (95% CI) 9.0-96.4), P=0.020)], reduced nasal resistance (MD -0.20Pa/cm3, 95% (-0.38)-(-0.02), P=0.028), and changed respiratory muscle strength variables (P>0.05). No correlation was found between the anatomical dimensions of the airway and the functional airway parameters (P>0.05). CONCLUSIONS: The short-term airway volumetric changes secondary to MARPE were not significant. The influence of MARPE appliances on breathing is still not clear. Registration PROSPERO database (CRD42020183340).

Variability of the maxillary suture maturation and density in the subjects with different sex and growth status.

INTRODUCTION: The objective of this study was to classify median palatine suture (MPS) maturation type in young and adult patients. Additionally, we compared MPS maturity type and density based on sex and growth status. MATERIALS AND METHODS: In this retrospective cone beam computed tomography study, we included a total of 221 subjects, grouped based on sex and growth status. Once scans were aligned and oriented in the sagittal view, we conducted our evaluations on the axial sections. Based on interdigitation and shape, the MPS were categorized into Maturation Types A through E. Additionally, MPS density was measured as Hounsfield unit equivalent pixel intensity value scale for anterior and posterior sutural regions. RESULTS: The majority of male (39%) and female (42%) subjects had MPS Maturation Type C. A maximum number of growing (42%) patients had Type C and nongrowing subjects (39%) had Type E sutures. The sex comparison showed significantly lower (p < .001) MPS density for both anterior and posterior regions in males when compared to females. Additionally, for the posterior region, nongrowing males had significantly lower (p < .001) MPS density when compared to nongrowing females. Subgroup comparisons of the MPS densities between growing and nongrowing males and growing and nongrowing females showed a significant difference (p < .001). CONCLUSION: Classification of the MPS based on the maturation types provides a reliable predictor for orthodontic treatment planning. MPS density is significantly higher in females as compared to males. Similarly, nongrowing individuals have significantly higher MPS density compared to growing individuals for both anterior and posterior locations.