Maxillomandibular Discrepancy Research Articles

A New Approach for the Assessment of True Maxillomandibular Sagittal Relationship: A Zeta Angle.

The assessment of sagittal skeletal dysplasia is crucial for accurate diagnosis and treatment planning, thus necessitating a thorough evaluation. A novel cephalometric parameter, known as the Zeta angle, was proposed in this study for the evaluation of the maxillomandibular relationship in the sagittal plane. This observational study was carried out using 291 pre-treatment lateral cephalograms of participants aged between 15 and 25 years, categorized into skeletal class I, II, and III relationships based on Wits appraisal, ANB angle, and Beta angle. The individuals reported to the Department of Orthodontics from January 2021 to October 2023, Manav Rachna Dental College, Manav Rachna International Institute of Research and Studies, Faridabad. The Zeta angle was constructed using three skeletal reference points as point Pt (pterygoid), point M (center of premaxilla), and point Pm (suprapogonion)and was measured perpendicular to point M on the Pt-Pm line and the M-Pm line to determine the severity and type of maxillomandibular discrepancy in the sagittal plane. Statistical tests were used to obtain the mean values for the Zeta angle. Analysis of variance (ANOVA), followed by the Bonferroni post-hoc test, was used to assess skeletal differences between the groups. Receiver operating characteristic (ROC) curves were used to evaluate the sensitivity and specificity of this angle. The results indicated that a Zeta angle between 57° and 64° had a class I skeletal jaw pattern, a Zeta angle less than 57° indicated a class II skeletal jaw pattern, and a Zeta angle greater than 64° indicated a class III skeletal jaw pattern. ROC curves showed that a Zeta angle less than 57.5° had 80% sensitivity and 82.5% specificity in distinguishing class II from the class I subset. A Zeta angle greater than 64.5° has a sensitivity and specificity of 92.5% in distinguishing class III from the class I subset. The Zeta angle may serve as an additional diagnostic tool for the reliable determination of sagittal jaw relationships due to its establishment based on stable anatomical points, thus remaining unaffected by jaw rotations and orthodontic treatments.

Comparison between one-jaw and two-jaw designs in virtual surgery planning for patients with class III malocclusion

Orthognathic surgery is highly effective for treating maxillomandibular discrepancies in patients with class III malocclusion. However, whether one- or two-jaw surgery should be selected remains controversial. Our study aimed to evaluate quantitative differences between one-jaw and two-jaw surgical designs.In total, 100 consecutive patients with skeletal class III malocclusion who underwent orthognathic surgery with preoperative three-dimensional simulation between August 2016 and November 2021 were recruited. Based on the same final occlusal setup, a two-jaw surgery design and two types of one-jaw design were created. In total, 400 image sets, including preoperative images and three types of surgical simulation, were measured and compared.The one-jaw mandibular setback design led to improvement in most cephalometric measurements and facial symmetry. Although the one-jaw maxillary advancement design improved the ANB angle and facial convexity, it induced maxillary protrusion and reduced facial symmetry. Compared with the other designs, the two-jaw design provided significantly closer cephalometric measurements to the normative values, better symmetry, and less occlusal cant.Overall, the two-jaw design provided a quantitatively better facial appearance in terms of symmetry, proportion, and profile. Although an optimal surgical design necessitates thorough preoperative evaluation and a shared decision-making process, two-jaw surgery can be considered for improving overall facial esthetics and harmony.

Skeletal Class III phenotype: Link between animal models and human genetics: A scoping review.

This study aimed to identify evidence from animal studies examining genetic variants underlying maxillomandibular discrepancies resulting in a skeletal Class III (SCIII) malocclusion phenotype. Following the Manual for Evidence Synthesis of the JBI and the PRISMA extension for scoping reviews, a participant, concept, context question was formulated and systematic searches were executed in the PubMed, Scopus, WOS, Scielo, Open Gray, and Mednar databases. Of the 779 identified studies, 13 met the selection criteria and were included in the data extraction. The SCIII malocclusion phenotype was described as mandibular prognathism in the Danio rerio, Dicentrarchus labrax, and Equus africanus asinus models; and as maxillary deficiency in the Felis silvestris catus, Canis familiaris, Salmo trutta, and Mus musculus models. The identified genetic variants highlight the significance of BMP and TGF-β signaling. Their regulatory pathways and genetic interactions link them to cellular bone regulation events, particularly ossification regulation of postnatal cranial synchondroses. In conclusion, twenty genetic variants associated with the skeletal SCIII malocclusion phenotype were identified in animal models. Their interactions and regulatory pathways corroborate the role of these variants in bone growth, differentiation events, and ossification regulation of postnatal cranial synchondroses.

Prevalence of adenoid hypertrophy among 12-year-old children and its association with craniofacial characteristics: a cross-sectional study

BackgroundIdentifying the prevalence of adenoid hypertrophy (AH) and craniofacial factors associated with this condition requires studies with random sampling from the general population, and multiple criteria can be used for assessing AH on lateral cephalometric radiograph (LCR). The present analysis represents the first report performed according to these requirements in a large cross-sectional sample of children.MethodsLCRs of 517 12-year-old children (286 males, 231 females) randomly selected from the general population were retrospectively retrieved. AH was defined using three criteria (At/Nd, Ad-Ba/PNS-Ba, 1-Npaa/Npa), and twelve craniofacial variables were measured (SNA, SNB, ANB, Wits, Cd-Gn, MnP^SN, MxP^MnP, TPFH/TAFH, OPT^SN, C2ps-C4pi^SN, H-CV, H-FH). Skeletal characteristics were compared between children with and without AH using Mann–Whitney U test. Binary logistic regression (adjusted for sex and skeletal growth) was used to independently quantify the association between craniofacial factors and AH.ResultsThe prevalence of children with AH was 17.6% (according to At/Nd), 19.0% (according to Ad-Ba/PNS-Ba), and 13.9% (according to 1-Npaa/Npa). Children with AH presented greater antero-posterior jaw discrepancy (larger ANB, smaller SNB), greater mandibular divergence (larger MnP^SN), forward head posture (larger OPT^SN and C2ps-C4pi^SN), and anteriorly positioned hyoid bone (larger H-CV). Larger SNA (OR = 1.39–1.48), while smaller SNB (OR = 0.77–0.88) and Wits (OR = 0.85–0.87), were associated with greater likelihood of having AH, independently from the assessment method used.ConclusionsThe prevalence of children with AH ranged from 13.9 to 19.0% based on LCR. Greater antero-posterior maxillo–mandibular discrepancy and mandibular retrusion were independently associated with higher likelihood of having AH.

A study of transverse maxillomandibular discrepancy and dental compensation in early mixed dentition with skeletal Class III malocclusion without posterior crossbite.

To evaluate transverse maxillomandibular discrepancy and dental compensation in first molar areas in 7- to 9-year-old children with skeletal Class III malocclusion without posterior crossbite using cone-beam computed tomography (CBCT). The sample of this retrospective study consisted of 60 children (7 to 9 years old), who were divided into the skeletal Class III malocclusion group (study group, skeletal Class III malocclusion without posterior crossbite, N = 31) and the Class I occlusion group (control group, Class I occlusion with one or two impacted teeth, N = 30). CBCT data were obtained from the database of the Department of Radiology of Hospital of Stomatology, Shandong University. For three-dimensional reconstruction of the head, the dental arch width, basal bone width, and buccolingual inclination angle were measured using MIMICS 21.0 software. Independent-sample t tests were used to compare the two groups. The mean age of the children was 8.18±0.83years. The width of the maxillary basal bone was significantly smaller in the skeletal Class III malocclusion group (59.75 ± 3.14 mm) than in the Class I occlusion group (62.39 ± 3.01 mm) (P < 0.01). The mandibular basal bone width was significantly larger in the skeletal Class III malocclusion group (60.00 ± 2.56 mm) than in the Class I occlusion group (58.19 ± 2.42 mm) (P < 0.01). The difference in the width of the maxillary and mandibular bases in the skeletal Class III malocclusion group (-0.25 ± 1.73 mm) was significantly different from that in the Class I occlusion group (4.20 ± 1.25 mm) (P < 0.01). However, there was no significant difference in the upper or lower dental arch width between the two groups (P > 0.05). The buccal inclination of the maxillary molars in the skeletal Class III malocclusion group (31.4° ± 8.9°) was significantly higher than that in the Class I occlusion group (17.64° ± 7.3°) (P < 0.01), as was the lingual inclination angle of mandibular molars (45.24° ± 8.3° vs. 37.96° ± 10.18°; P < 0.01). Transverse maxillary and mandibular discrepancies in the posterior area and transverse dental compensation were found in the early mixed dentition of patients with skeletal Class III malocclusion without posterior crossbite. This suggests that even in the absence of posterior crossbite, maxillary expansion can be attempted to correct the maxillomandibular transverse discrepancy.

Correlation between findings of the oral myofunctional clinical assessment, pressure and electromyographic activity of the tongue during swallowing in individuals with different orofacial myofunctional disorders.

To correlate the findings regarding the myofunctional orofacial examination, tongue pressure and surface electromyography (sEMG) of deglutition in individuals with different orofacial myofunctional disorders. 44 patients (20 males and 24 females, aged between 17 and 63 years old) with different orofacial myofunctional changes were clinically assessed using the Expanded Protocol of Orofacial Myofunctional Evaluation with Scores (OMES-E). In addition, the range of mandibular movements and facial anthropometry were measured, along with the assessment of the tongue pressure (tip and dorsum) and of the electrical activity of the suprahyoid muscles during deglutition, using surface electromyography (sEMG). The statistical analysis found weak correlations between tongue dorsum pressure values, suggesting that the greater the measurement of the lower third of the face, the lower the pressure of the tongue dorsum; the greater the measurement of the overlaps (vertical and horizontal), the higher the pressure of the tongue dorsum; the higher the score from the orofacial evaluation and orofacial functions assessment, the higher the pressure of the tongue dorsum; and the higher the pressure of the tongue dorsum, the higher the pressure of the tongue tip. The present study results indicate that the orofacial myofunctional changes found in different groups of patients are more related to the maxillomandibular discrepancies than to the pathologies investigated herein.

Correlação entre achados da avaliação clínica miofuncional orofacial, a pressão e a atividade eletromiográfica da língua na deglutição em indivíduos com diferentes alterações da motricidade orofacial

ABSTRACT Purpose To correlate the findings regarding the myofunctional orofacial examination, tongue pressure and surface electromyography (sEMG) of deglutition in individuals with different orofacial myofunctional disorders. Methods 44 patients (20 males and 24 females, aged between 17 and 63 years old) with different orofacial myofunctional changes were clinically assessed using the Expanded Protocol of Orofacial Myofunctional Evaluation with Scores (OMES-E). In addition, the range of mandibular movements and facial anthropometry were measured, along with the assessment of the tongue pressure (tip and dorsum) and of the electrical activity of the suprahyoid muscles during deglutition, using surface electromyography (sEMG). Results The statistical analysis found weak correlations between tongue dorsum pressure values, suggesting that the greater the measurement of the lower third of the face, the lower the pressure of the tongue dorsum; the greater the measurement of the overlaps (vertical and horizontal), the higher the pressure of the tongue dorsum; the higher the score from the orofacial evaluation and orofacial functions assessment, the higher the pressure of the tongue dorsum; and the higher the pressure of the tongue dorsum, the higher the pressure of the tongue tip. Conclusion The present study results indicate that the orofacial myofunctional changes found in different groups of patients are more related to the maxillomandibular discrepancies than to the pathologies investigated herein.

The 'Powerbite' and surgical rapid expansion.

Adults presenting with transverse maxillomandibular discrepancies in Class III skeletal patterns, asymmetries and anterior open bite can be challenging to treatment plan and manage. Therefore, they often necessitate a multidisciplinary approach, with surgical input from the oral and maxillofacial team. It can be difficult to assess how much the maxilla needs to be expanded after surgery in these patients, as the upper and lower teeth cannot be brought into occlusion. We aim to discuss the use of a device we have come to call the 'Powerbite', which is used intra-orally to assess the expansion of the maxilla after surgically assisted rapid palatal expansion (SARPE) and establish when expansion is sufficient to accommodate the mandibular arch. This device is not novel, last described in 1986 in the Journal of Orthodontics.

Non-Surgical Transversal Dentoalveolar Compensation with Completely Customized Lingual Appliances versus Surgically Assisted Rapid Palatal Expansion in Adults-The Amount of Posterior Crossbite Correction.

The aim of this study was to compare the crossbite correction of a group (n = 43; f/m 19/24; mean age 27.6 ± 9.5 years) with surgically assisted rapid palatal expansion (SARPE) versus a non-surgical transversal dentoalveolar compensation (DC) group (n = 38; f/m 25/13; mean age 30.4 ± 12.9 years) with completely customized lingual appliances (CCLA). Arch width was measured on digital models at the canines (C), second premolars (P2), first molars (M1) and second molars (M2). Measurements were obtained before treatment (T0) and at the end of lingual treatment (T1) or after orthodontic alignment prior to a second surgical intervention for three-dimensional bite correction. There was no statistically significant difference (p &gt; 0.05) in the amount of total crossbite correction between the SARPE and DC-CCLA group at C, P2, M1 and M2. Maxillary expansion was greater in the SARPE group and mandibular compression was greater in the DC-CCLA group. Crossbite correction in the DC-CCLA group was mainly a combination of maxillary expansion and mandibular compression. Dentoalveolar compensation with CCLAs as a combination of maxillary expansion and mandibular compression seems to be a clinically effective procedure to correct a transverse maxillo-mandibular discrepancy without the need for surgical assistance.

A New Approach to Diagnosis to Posterior Cross Bite: Intraoral Photography and Wala Ridge.

A posterior crossbite is an occlusion disorder that occurs in the transverse plane. It occurs when the buccal cusps of the upper premolars and molars engage lingually with the buccal cusps of the lower teeth. It can be unilateral or bilateral (involving one or more teeth) in the primary, mixed, or permanent dentition. A crossbite may appear in early dentition stages and it can be dental or functional. It can lead to skeletal crossbite in mixed dentition. Therefore, early diagnosis and treatment are crucial. Material and methods: The selected sample included 204 patients in growing stage divided into two groups: a study group of 102 patients with posterior crossbite and a control group of 102 patients without malocclusion. To analyze the pathology, intraoral frontal photographs and study models were taken, in which the bone component was measured from the Wala Ridge. Results: The use of the photographs to study the Wala Ridge was confirmed. The mean maxillary width was 57.8 mm (SD 1.7) and mandibular width was 56.4 mm (SD 1.7) for the control group, with a maxillomandibular difference of 1.4 mm (SD 0.7); and 52.7 mm (SD 3.7) and 55.5 mm (SD 3.6), respectively, with a maxillomandibular difference of −2.8 mm (SD 1.4) for the study group. A higher maxillomandibular discrepancy was observed in patients with a posterior crossbite that involved more than one tooth in addition to the permanent first molar. It was also higher in patients with bilateral posterior crossbite. Conclusions: Intraoral frontal photography can be used as a diagnostic method to measure the maxillomandibular difference using the Wala Ridge.

Skeletal class III malocclusion and bilateral sagittal osteotomy: a concise systematic review

Introduction: In the context of skeletal class III malocclusion, orthognathic surgery is a standardized procedure used to improve the patient's facial appearance and to correct maxillary and mandibular deformities resulting from malocclusions, disease, or trauma. Thus, bilateral sagittal osteotomy of the mandibular ramus is a technique widely used in OS for the correction of mandibular deformities. Objective: the present study evaluated, through a concise systematic review, the main considerations of mandibular advancements through mandibular bilateral sagittal osteotomies in patients with skeletal class III malocclusion. Methods: Clinical studies with qualitative and/or quantitative analysis were included, following the rules of the systematic review-PRISMA. Results: A total of 115 articles were found involving “skeletal class III malocclusion". A total of 45 articles were evaluated in full, and 22 were included and discussed in this study. Bilateral sagittal osteotomy (BSO) is the most used technique in mandibular OS, allowing mandibular movements in the sagittal, vertical, and transverse directions. Several studies show good results and few complications. The size of this space is proportional to the mandibular advancement and/or rotation movements required by the patient's maxillomandibular discrepancy. The prevention of inferior mandibular edge defects is an important issue when planning an BSO traditional non-grafted BSO technique produces a large proportion of defects in the lower edge of the mandible. In cases where the advancement is greater than 10 mm and/or the patient is over 30 years old, the risk of the mandibular defect increases significantly. Also, using a bone graft in the intersegmental gap of a sagittal branch osteotomy is considered an effective clinical method to ensure the desirable intersegmental position as it helps to easily maintain the space. Conclusion: The results showed that bilateral sagittal osteotomy is the most used technique in mandibular orthognathic surgery, allowing mandibular movements in the sagittal, vertical, and transverse directions, with good results and few complications. Furthermore, a bone graft can accelerate bone formation in orthognathic surgery.

A Preliminary Management Algorithm for Velopharyngeal Insufficiency in Cleft-Orthognathic Patients.

Patients born with a cleft palate often suffer from velopharyngeal insufficiency (VPI) due to the soft palate musculature's abnormal structure. Surgical correction of the palate at a young age can hinder maxillary growth, requiring surgical correction of the maxillomandibular discrepancy at skeletal maturity. Orthognathic surgery can then cause or further exacerbate VPi in these patients. The purpose of this paper is to assess cleft-orthog-nathic patients under the lens of persistent or newly-developed VPi, to understand outcomes and generate a targeted management algorithm. A retrospective study was performed inspecting cleft-orthognathic patients presenting to a single surgeon. Patients with sufficient follow-up were placed into predefined algorithmic cohorts by their VPi development pattern in relation to orthognathic surgery. They were further stratified into groups by level of adherence to our algorithm to evaluate VPi outcomes. Demographic factors, risk factors, and outcomes were compared between groups via Welch t test and Fisher exact test. Fifty-one patients were examined, including 16 with VPI. Velopharyngeal insufficiency fully resolved amongst all algorithmically adherent patients and remained in nonadherent patients ( P < 0.001). Our targeted algorithm may improve symptoms and the management of VPI in cleft-orthognathic patients. Multi-centered studies with larger sample sizes and prospective studies are encouraged to validate our proposed treatment algorithm further.

Effectiveness of clonidine as a preanesthetic drug on intra operative blood loss in oral and maxillofacial surgery

Controlled hypotension during a surgical procedure is a way to decrease blood pressure and subsequently to improve the field of operation. Clonidine is an antihypertensive drug which acts through facilitation of Alph-2 post-synaptic receptors and in addition to its antihypertensive, anti-anxiety and analgesic effects, its beneficial effects in reducing the bleeding during. Correction of maxillomandibular discrepancies may necessitate performing osteotomy on both the jaws in several cases. Bimaxillary orthognathic surgery and rhinoplasty are procedures associated with significant blood making proper hemostasis essential for a surgical field that is free of excessive blood, reduced postoperative swelling, and appropriate surgical results. The aim of this systematic review is to assess the effectiveness of Clonidine as a pre-anesthetic drug on intraoperative blood loss in maxillofacial surgery. The Databases of PubMed, Cochrane and Google scholar were searched for the related topics along with a complimentary manual search of all oral surgery journals till January 2021. Articles were selected based on the inclusion criteria, which included all RCTs. From this study it is concluded that clonidine premedication is effective in reducing intraoperative blood loss as well as providing hemodynamic stability in patients undergoing different maxillofacial surgeries.

Coronal Mentoplasty: Complementary Technique in Orthognathic Surgery: Cases Report

The harmony and facial aesthetics are the result of an adequate proportion between the thirds facial, where the concern for these parameters is in increasing demand. The maxillo-mandibular discrepancies both vertical and horizontal lead to a bad positioning of the tissues, causing alterations in the functionality and aesthetics that today are corrected with increasingly specific procedures.

Changes in the craniofacial structures and esthetic perceptions of soft-tissue profile alterations after distalization and Herbst appliance treatment

The purpose of this prospective clinical trial is to evaluate the changes of soft tissues and designate the esthetic perceptions of children with Class II malocclusion after Herbst appliance therapy and maxillary molar distalization using stereophotogrammetry. Thirty patients were allocated either to Herbst (6 boys and 9 girls; mean age=11.60±0.82years) or distalization (4 boys and 11 girls; mean age=11.46±1.30years) groups. Dentoskeletal and soft-tissue treatment changes were examined objectively by cephalometric analysis and stereophotogrammetry, respectively. Pre- and posttreatment profile views were evaluated subjectively by orthodontists and laypeople using the 7-point Likert scale. Intra- and intergroup comparisons for the repeated measurements were performed with 2-way variance analysis. Bonferroni test was used for multiple comparisons (P≤0.05). Greater skeletal changes were observed in the Herbst group than in the distalization group. Maxillary incisor retrusion and mandibular incisor protrusion were observed in the distalization and Herbst groups, respectively. Stereophotogrammetric measurements showed that mandibular body length and lower and anterior facial height increased in both treatment groups. Convexity angle (P=0.020) and labiomental angle (P=0.033) were greater in the Herbst group than the distalization group. The skeletal contribution to correction of maxillomandibular discrepancy was greater in the Herbst group than the distalization group. Significant profile improvements were recorded for both groups with treatment. After both treatments, orthodontists were found to have higher rates of detection in the profiles than laypeople. The esthetic contribution of treatments to the facial profile was found similar in both groups.

Adenotonsilectomia e Classe II esquelética – estudo de casocontrole

Introduction: The maxillomandibular lateral growth imbalance with mandibular retrusion related to the maxilla indicates the skeletal Class II pattern. This craniofacial morphological abnormality is often attributed to nasorespiratory obstruction due to pharyngeal and palatine tonsils hypertrophy. The adenotonsillectomy is indicated to young patients with respiratory obstruction. However, there is no information in the scientific literature concerning the impact of tonsils surgically removal on craniofacial growth and development. Objective: To identify the association between adenotonsillectomy and skeletal Class II. Material and Methods: An unpaired case-control study was performed. Adult subjects who agreed to participate filled a questionnaire and after identification of the skeletal pattern through radiographic cephalometric analysis were allocated into two groups: CASE GROUP composed of 23 subjects with skeletal Class II malocclusion and CONTROL GROUP composed of 27 subjects without skeletal Class II malocclusion. With specific software the images were evaluated and measured to compare craniofacial measurements between the experimental groups and this data was interpreted to verify the association between skeletal Class II and the occurrence of adenotonsillectomy in early childhood. Results: the adenotonsillectomy demonstrated protective potential for skeletal Class II development due to a strong epidemiological association between adenotonsillectomy and skeletal Class II anteroposterior discrepancy (ORC = 0.33), without gender interference (ORA = 0.91). Conclusions: Among the long-term benefits of performing adenotonsillectomy in early childhood, it may be considered the prevention of craniofacial growth alterations such as Class II maxillomandibular discrepancy.

Clinical applications of miniscrews that broaden the scope of non-surgical orthodontic treatment.

Previously, in the case of malocclusion owing to skeletal discrepancy in adults, the amount of tooth movement was limited since there was no reliable skeletal anchorage device. The only way to treat this case was by repositioning the maxilla and mandible via orthognathic surgery, but most patients are reluctant to undergo surgery owing to the risk and expenses incurred. However, with the current introduction and use of miniscrews as temporary anchorage devices, the entire dental arch can be relocated to a target position without surgery, thus broadening the scope of non-surgical orthodontic treatment compared to the past. For a non-surgical approach to improve skeletal discrepancy, anteroposterior, vertical and transverse displacements of the dental arch are necessary. In this case, the localization of the centre of resistance of the whole arch must precede the appliance design with an appropriate biomechanical design. Especially, in the transverse dimension, the envelope of discrepancy is reportedly narrow, and the tooth movement must accompany the orthopaedic correction involving the midpalatal suture expansion. Recently, in adults with transverse maxillomandibular discrepancy, miniscrew-assisted rapid palatal expansion (MARPE) can be performed. Moreover, compared to surgically assisted rapid palatal expansion, MARPE reduces the cost to the patient and achieves clinically acceptable stable maxillary expansion. In this article, we will discuss the role of total arch movement and MARPE in widening the scope of non-surgical orthodontic treatment, despite the inherent limitations of miniscrews' mechanical aspects.

Orofacial clefts: treatment based on a multidisciplinary approach

Orofacial clefts: treatment based on a multidisciplinary approach

Stability of bimaxillary surgery involving intraoral vertical ramus osteotomy with or without presurgical miniscrew-assisted rapid palatal expansion in adult patients with skeletal Class III malocclusion.

ObjectiveThe aim of this study was to evaluate the stability of bimaxillary surgery involving bilateral intraoral vertical ramus osteotomy performed with or without presurgical miniscrew-assisted rapid palatal expansion (MARPE) in adult patients with skeletal Class III malocclusion.MethodsA total of 40 adult patients with skeletal Class III malocclusion were retrospectively divided into two groups (n = 20 each) according to the use of MARPE for the correction of transverse maxillomandibular discrepancy during presurgical orthodontic treatment. Serial lateral cephalograms and dental casts were analyzed until 6 months after surgery.ResultsBefore presurgical orthodontic treatment, there was no significant differences in terms of sex and age between groups. However, the difference of approximately 3.1 mm in the maxillomandibular intermolar width was statistically significant (p < 0.001). Two days after surgery, the mandible had moved backward and upward without any significant intergroup difference. Six months after surgery, the maxillary intercanine (2.7 ± 2.1 mm), interpremolar (3.6 ± 2.4 mm), and intermolar (2.0 ± 1.3 mm) arch widths were significantly increased (p < 0.001) relative to the values before presurgical orthodontic treatment in the MARPE group; these widths were maintained or decreased in the control group. However, there was no significant difference in surgical changes and the postsurgical stability between the two groups. No significant correlations existed between the amount of maxillary expansion and postsurgical mandibular movement.ConclusionsMARPE is useful for stable and nonsurgical expansion of the maxilla in adult patients with skeletal Class III malocclusion who are scheduled for bimaxillary surgery.

Improving accuracy of the intermediate splint in substantial intermaxillary sagittal discrepancies using an extra anterior anchorage point: technical note.

Background To describe a technical feature that increases the stability of the intermediate splint in patients where bimaxillary surgery with great maxillary/mandibular advancements are planned. Material and Methods Prospective evaluation of the intermediate splint dental vertical penetration in patients undergoing bimaxillary surgery where great sagittal discrepancy occur in the anterior sector between the upper and lower jaws when the intermediate splint is placed by adding an extra intermaxillary fixation (IMF) screw (2x9 mm) placed between the central incisors of the maxilla and fixed to the most anterior aspect of the intermediate splint following the direction of the sagittal maxillo-mandibular discrepancy from January to September 2018. Results The postoperative evaluation comparing the accuracy of conventional fixation versus fixation with an extra anterior anchorage point through photographic assessment and intraoral digital scanner demonstrated better dental penetration, and therefore improved intermediate splint precision with the latter in all cases Conclusions Our results suggest that this is a simple and safe technique that can be easily reproduced and optimizes the outcomes by increasing the accuracy of translation of the planned surgical movements to the operating room. Key words:Orthognathic surgery, intermediate splint, accuracy, intermaxillary fixation, bone screw.