Transverse effects after surgically assisted rapid maxillary expansion in the midpalatal suture using computed tomography

Bone Density of the Midpalatal Suture After Surgically Assisted Rapid Maxillary Expansion: A Retrospective Cohort Study

OBJECTIVES

To evaluate the bone density in the midpalatal suture after 10 months of surgically assisted rapid maxillary expansion (SARME) with the separation of the maxilla into 2 segments.

METHODS

Sixty multislice computed tomography (MCT) from 20 patients undergoing SARME were analyzed in 3 periods of time (1 MCT per patient on each occasion): (1) 1 week before surgery, (2) postsurgery immediately after completing the expander activation, and (3) 10 months after the expander activation. On all occasions, the bone density was measured in Hounsfield units on MCT scans in axial and coronal sections, in the anterior (A1), middle (A2), and posterior (A3) regions of the midpalatal suture.

RESULTS

The mean percentage values of bone density in Hounsfield units, from the 10-month postactivation period to preoperative in the A1, A2, and A3 regions were 68.38%, 38.21%, and 55.90%, respectively, in the axial norm, and 64.06%, 36.81%, and 55.50% in coronal norm (A1 = A3>A2), with no significant difference in the tomographic cuts (P >0.05). There was no correlation between patient age or amount of expansion in the expander and bone density.

CONCLUSIONS

The bone density in the midpalatal suture 10 months after SARME is lower than preexpansion. A denser new bone formation along the suture concentrates closer to the extremities rather than in the central region. Although the maturation of the new bone formation in the midpalatal suture is lower 10 months after SARME, it appears to be sufficient for satisfactory clinical results, regardless of patient age or the amount of expansion in the expander.

The effects of pterygomaxillary disjunction in surgically assisted rapid maxillary expansion: A systematic review and meta-analysis

OBJECTIVE

This study aims to assess the expansive effects of pterygomaxillary disjunction (PMD) in surgically assisted rapid maxillary expansion (SARME) surgery using a meta-analysis approach.

MATERIALS AND METHODS

The study conducted a comprehensive literature search across five databases: PubMed, Scopus, Medline, Embase, and Cochrane, adhering to the PRISMA 2020 guidelines. Dental alterations were assessed using either cone-beam computed tomography (CBCT) or dental casts, while skeletal changes were exclusively measured from CBCT scans. We analysed the dentoskeletal changes between PMD +/- groups and conducted a within-group comparison. The primary focus of the results was on the mean differences observed in pre- and post-operative measurements.

RESULTS

Dental expansion was larger in the PMD+ group but not statistically significant. Skeletal expansion showed a significantly larger expansion in the posterior region in the PMD+ group (P = .033). Without PMD, anterior palatal expansion was significantly larger (P = .03), and the buccal tipping of posterior teeth was also significantly larger (P = .011) to achieve acceptable dental expansion outcomes.

CONCLUSIONS

Both PMD +/- groups of SARME surgery can achieve satisfactory dental expansion outcomes. However, bone expansion and tooth inclination are also important factors that influence orthodontic treatment and post-expansion stability. By reducing the bony resistance with PMD, larger posterior palatal expansion and more parallel bony expansion are observed. In contrast, without PMD, there is smaller palatal expansion and greater tooth inclination in the posterior region. This could potentially lead to compromised periodontal conditions following expansion.

Can different osteotomies have an influence on surgically assisted rapid maxillary expansion? A systematic review

The purpose of this study was to systematically review the randomized and non-randomized clinical trials (RCT; nRCT) concerning the different available osteotomies for surgically assisted rapid maxillary expansion (SARME): pterygomaxillary disjunction (SARME + PD vs SARME-PD) and segmental Le Fort I osteotomy (2-piece vs 3-piece). Outcomes focused on skeletal, dental, upper airway changes, complications, and relapse. Two authors investigated five databases (PubMed, Cochrane Library, Google Scholar, Scopus, Web of Science) until August 2023. The Cochrane Collaboration Tool and the Newcastle-Ottawa scale were used for the quality assessment of the included RCTs and nRCTs, respectively. A total of 554 articles were retrieved and after duplicates removing and full-text reading, 40 studies were included. Two RCTs showed a low risk of bias, one an unclear risk and one a high risk. Among the non-RCTs, 15 studies showed a good quality, while 21 exhibited a fair quality score. SARME + PD resulted in more homogeneous posterior bone expansion, with minimal dental effects. No difference between 2-piece and 3-piece in asymmetric expansion was observed, although 3SO showed 1-2 mm of more transverse increase. The oropharynx minimum cross-sectional area, the nasopharynx and the oropharynx volume were greater in SARME + PD. Both dental and bone relapse can occur but no differences between the groups were observed. All osteotomies guaranteed a correction of transverse maxillary deficiency. Lower side effects were described in SARME + PD. Two-piece and 3-piece segmental Le Fort I osteotomies did not show any differences in the symmetry and amount of expansion.

Three-dimensional dentoskeletal changes following minimally invasive surgically assisted rapid palatal expansion: a prospective study

Dentoskeletal changes in minimally invasive surgically assisted rapid palatal expansion (SARPE) were evaluated using cone beam computed tomography (CBCT). This was a prospective study of 30 patients who underwent minimally invasive SARPE performed under local anaesthesia plus sedation by the same surgeon, in an ambulatory setting. Pre- and postoperative CBCT images were obtained for each patient. A statistically significant increase in the linear transverse dimensions of the maxilla occurred systematically. In the canine region, a mean increase of 5.84 mm occurred at the apex level and 7.82 mm at the crown level. These dimensions were 4.83 mm and 7.68 mm, respectively, in the molar region. The cross-sectional area of the maxilla increased by a mean 12.9 mm² at the palate level and 23.3 mm² at the crown level. Dental inclination to the buccal aspect was detected (mean 6.1° at the canines and 8.4° at the first molars). The alveolar process tipped buccally 10° at the molar level. Nasal width increased a mean of 3.0 mm at the canine level. Through a three-dimensional analysis, this study found that minimally invasive SARPE was effective in the correction of transverse maxillary discrepancies> 5 mm in non-growing patients. Although dental inclination to the buccal aspect occurred, significant expansion of the maxilla at the skeletal and dentoalveolar levels was confirmed.

Two- and Three-Segment Surgically Assisted Rapid Maxillary Expansion: A Clinical Trial

BACKGROUND

The literature shows no consensus on whether two- or three-segment surgically assisted rapid maxillary expansion is the best operative technique.

METHODS

The present clinical trial was designed to compare the outcome of two- and three-segment osteotomy surgically assisted rapid maxillary expansion. Thirty-two adult patients with transverse maxillary deficiency greater than or equal to 5 mm were randomly assigned to two- and three-segment groups (n = 16). Dimensional and psychological assessments (Oral Health Impact Profile and Brazilian Orthognathic Quality of Life Questionnaire) were carried out before surgical intervention and at one of the following time points: completion of expansion, removal of expanding device, 6 months after completion of expansion, or 10 months after completion of expansion. Dimensional assessments for asymmetric expansion of the maxilla and for changes in the area and volume of the palatine vault were performed on digital data from tomographic and laser scanning with the aid of an engineering inspection software.

RESULTS

No statistically significant differences were found in asymmetry or stability outcomes between groups. The psychological benefit provided by the three-segment technique did not spread through the domains of the quality-of-life questionnaires.

CONCLUSIONS

The current findings suggest that three-segment surgically assisted rapid maxillary expansion outcomes do not exceed those obtained with its two-segment counterpart regarding symmetry of maxillary expansion and stability of area and volume of the palatine vault. Furthermore, psychological nuances evidenced in two- and three-segment groups with the tools used play a limited, short-lasting role, or a specific, more sensitive assessment tool needs to be developed.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Novel Digital Measurement Technique to Analyze the Palatine Suture Expansion after Palatine Rapid Maxillary Expansion Technique

The aim of the study was to validate a novel digital measurement method to quantify the volume of the midpalatal suture after rapid maxillary expansion (RME). Material and methods: Eight patients with maxillary skeletal transverse deficiency were submitted to palatine suture expansion using the McNamara orthodontic appliance during a period of nine months. After 30 days of treatment, all patients were exposed postoperatively to a cone-beam computed tomography (CBCT) scan. Afterwards, the scans were uploaded into the three-dimensional orthodontic-planning software to allow the volumetric assessment of the palatine suture expansion through palatine rapid maxillary expansion using a McNamara appliance. The repeatability was analyzed by repeating twice the measures by a single operator and reproducibility was analyzed by repeating three times the measures by two operators, and Gage R&R statistical analysis was performed. Results: The expansion of the midpalatal suture by means of the rapid maxillary expansion technique, in terms of digital volume measurement, showed a repeatability value of 0.09% and between the two operators a reproducibility value of 0.00% was shown. Conclusions: The novel measurement technique demonstrated a high repeatability and reproducibility rate for volume assessment of the palatine suture expansion through palatine rapid maxillary expansion technique.

Skeletal and dental effects of surgically assisted rapid palatal expansion: a systematic review of randomized controlled trials

BACKGROUND

Surgically assisted rapid maxillary expansion (SARME) is a surgical technique developed to correct transverse discrepancies in skeletally mature patients. However, there is limited evidence concerning the immediate skeletal and dental changes obtained only due to SARME.

OBJECTIVE

The aim of the present systematic review is to investigate the immediate skeletal and dental effects of SARME in adult patients with transverse maxillary hypoplasia.

SEARCH METHODS

An electronic search of the literature in MEDLINE, The Cochrane Library, Lilacs and Scopus databases was performed.

SELECTION CRITERIA

Only randomized controlled trials (RCTs) studies investigating the skeletal and dental effects of SARME procedures in adult patients were included.

DATA COLLECTION AND ANALYSIS

The included studies received a methodological quality scoring according to the revised Cochrane risk-of-bias tool for randomized trials. The quality of evidence was assessed by means of the Grading Recommendation Assessment, Development and Evaluation (GRADE) system. For each included study and for each analysed parameter, the difference in means and 95 per cent confidence interval was calculated between baseline and immediate post-expansion. A meta-analysis of original outcome data, if possible, was conducted.

RESULTS

Nine articles were selected. The methodological quality ratings indicated that one study was at low risk of bias, seven presented some concerns and only one was at high risk of bias. In all the included studies, the SARME procedure resulted in a significant expansion of the maxillary transverse dimension. The meta-analysis compared skeletal and dental inter-molar width before and after treatment: the mean difference was of 3.3 mm (2.8-3.9) and 7.0 mm (6.1-7.8), respectively (P-value less than 0.001). The quality of evidence was low-moderate.

CONCLUSIONS

SARME is effective in obtaining a significant expansion of the maxillary transverse dimension. However, the immediate SARME effect is mainly a molar expansion rather than a pure bone transverse widening of the maxilla.

REGISTRATION

The review protocol was registered at PROSPERO database with the registration number CRD42018117967.

Effect of the pterygomaxillary disjunction on surgically assisted rapid palatal expansion in context of orthodontic treatment

OBJECTIVE

This retrospective study analyzed the dentoalveolar effects of pterygomaxillary disjunction (PMD) in surgically assisted rapid palatal expansion (SARPE) after orthodontic treatment.

STUDY DESIGN

Virtual study casts before and after orthodontic treatment involving SARPE were analyzed in 12 patients without (-) PMD and 15 patients with (+) PMD. Linear and angular measurements and maximum deviations on the alveolar ridge and hard palate were determined.

RESULTS

Dental arch widths in the first molars of the (-) and (+) PMD groups increased to 6.07 ± 2.11 mm and 6.61 ± 2.33 mm (P = .96) and the corresponding axial angles increased to 0.34 ± 9.45 degrees and 2.39 ± 9.59 degrees (P = .58), respectively. The palatal angles changed by about 0.10 ± 11.50 degrees and 1.74 ± 14.56 degrees (P = .75) in the (-) and (+) PMD groups and the maximum labial deviations at the alveolar ridge were 3.04 ± 0.76 mm and 3.22 ± 1.16 mm (P = .65) for the (-) and (+) PMD groups, respectively. Statistically significant differences were found before and after surgery (P < .04), but no significant differences were observed in PMD after orthodontic treatment.

CONCLUSIONS

SARPE led to a significant transverse expansion, and the dental effects were more than the skeletal effects. We did not find a significant difference between both surgical techniques with regard to the anterior and posterior parts of the maxilla or the corresponding dentition.

Adjustable selective maxillary expansion combined with one-stage maxillomandibular surgery: A prospective study of osseous widening in fifty-five consecutive patients

OBJECTIVE

SARME is often considered to be the only available treatment for significant or severe maxillary transverse palatal deficiencies (MTD) in skeletally-mature patients. Despite this observation, the aim of our study was to assess a new type of maxilla distraction osteogenesis. Using two innovative tools, we performed selective expansion: the site to be widened and the amount of increase were both pre-selected. Patients were treated in a single maxillomandibular procedure. Our study focuses primarily on the extent of osseous widening.

STUDY DESIGN

Post-expansion computed tomography data from 55 non-syndromic patients were included in a prospective study and analyzed in two planes for transverse skeletal widening. Of the 55 patients, 16 underwent isolated posterior distraction for severe posterior endognathia (group I), and 39 were treated in both segments (group II). Diastemas and anterior spaces permitted resolution of crowding and patients with a small, narrow, tapering arch were given a more rounded form. All patients underwent a complete Le Fort I with down fracture. Two novel devices were used: first, an adjustable distractor to achieve an angular opening; and secondly, in group II, new modular plates interlocked for osteosynthesis to provide stability and anterior expansion.

RESULTS

In group I, analysis of the width of the gain showed significant posterior values decreasing from back to front, a result never achieved with the SARME procedure. The mean osseous gain at first molars was 7.1 mm. When anterior space was required in group II, it was created as wide as needed (mean 4.2 mm, at canine level) with good preservation of the 1st molar space gain (mean 6.8 mm).

CONCLUSION

Total Le Fort I osteotomy associated with two innovative devices provides a new, segmental and adaptable approach for transverse distraction osteogenesis. We demonstrate a good match with the dental enlargement required. All patients were managed in a single orthognathic procedure for all the anomalies to be treated. Long-term results show good stability.

The effects of maxillary expansion on the soft tissue facial profile

Purpose

The aims of this retrospective study were to evaluate the possible changes in soft tissue facial profile induced by orthopedic rapid maxillary expansion (RME) and surgically assisted rapid maxillary expansion (SARME), and to correlate them with the underlying hard tissue alterations.

Materials and Methods

16 patients who received bone borne SARME and 25 patients who were subjected to RME using metal cast splint hyrax appliance were analyzed retrospectively. This research was conducted on lateral cephalometric radiographs taken on 2 occasions: before expansion (T1) and at the beginning of any further orthodontic treatment (T2). Investigated lateral cephalometric parameters consisted of Holdaway soft tissue measurements with some supplementary soft tissue, skeletal and dental assessments.

Results

The acquisition of T2 cephalograms which conforms to the initiation of further orthodontic treatment corresponded to 83.25±3.51 days for SARME and 85.68±4.37 days for RME after the expansion was completed. The only significant change in soft tissue profile of the SARME group was a decrease in upper lip thickness (p<0.05), whereas in the RME group, decrease in soft tissue facial profile angle and increase in H angle were found to be statistically significant (p<0.05 for each). For the RME group, the changes in soft tissue facial profile angle and H angle correlated only with the changes in SNB angle (p<0.05).

Conclusion

While bone-borne SARME did not seem to possess the potential to alter soft tissue profile, tooth-borne RME caused a more convex soft tissue profile related to a reduction in SNB.

Does pterygomaxillary disjunction in surgically assisted rapid maxillary expansion influence upper airway volume? A prospective study using Dolphin Imaging 3D

Surgically assisted rapid maxillary expansion has been used for the treatment of transverse maxillary deficiency. This prospective study aimed to evaluate the effect of this surgery (with or without pterygomaxillary disjunction) on the upper airway volume. The patients were randomly divided into two groups: without pterygomaxillary disjunction (-PD) and with pterygomaxillary disjunction (+PD). Eleven patients per group were estimated to obtain a representative sample (90% of power and 95% of confidence level). Volumetric images of cone beam computed tomography scans were obtained preoperatively, immediately after Hyrax screw stabilization and 6 months after Hyrax screw stabilization. Volumetric measurements of the nasal cavity, maxillary sinuses, nasopharynx, and oropharynx, and of the minimum oropharynx cross-sectional area were obtained using Dolphin 3D Imaging Software. The final sample consisted of 25 adult individuals (+PD group, n=12; -PD group, n=13). In the +PD group, we observed a statistically significant increase immediately after Hyrax screw stabilization for the nasopharynx volume (P=0.003), oropharynx volume (P=0.007) and oropharynx cross-sectional area (P=0.001). Pterygomaxillary disjunction resulted in a significant (P <0.05) increase in volumetric measurements of the nasopharynx and minimum oropharynx cross-sectional area 6 months after the expander device stabilization.

The value of cone beam computed tomography imaging in surgically assisted rapid palatal expansion: a systematic review of the literature

This study aimed to evaluate the reliability of cone-beam computed tomography (CBCT) imaging of the maxillary structures and the postoperative dentoskeletal, nasal airway, periodontal, and facial soft tissue changes after surgically assisted rapid palatal expansion (SARPE). A systematic review of the literature on CBCT analysis of SARPE was performed. The PubMed, Embase, and Cochrane Library databases were searched. Nine articles were included, involving a total of 228 patients. The general trend was tooth-borne distraction with pterygomaxillary dysjunction. A systematic increase in all transverse dimensions at the dentoalveolar and dental levels, as well as a certain degree of tipping and extrusion of the anchorage teeth and tipping of the skeletal segments, was detected. Soft tissue findings reflected the underlying dentoalveolar changes. A decrease in the buccal alveolar bone thickness and alveolar crest level occurred. Results confirm that CBCT is an accurate and reliable method to assess anatomical changes after SARPE. Although this systematic review provides valuable preliminary information about the effects of SARPE, results should be interpreted with caution due to the low level of evidence of the publications, great heterogeneity among study groups regarding outcome variables and surgical-orthodontic protocols, and lack of long-term data.

Evaluation of opening pattern and bone neoformation at median palatal suture area in patients submitted to surgically assisted rapid maxillary expansion (SARME) through cone beam computed tomography

Surgically assisted rapid maxillary expansion (SARME) is the treatment of choice to adult patients even with severe transversal maxillary discrepancies. However, the adequate retention period to achieve the bone remodeling, thus assuring treatment stability, is controversial.Objective To evaluate the opening pattern and bone neoformation process at the midpalatal suture in patients submitted to surgically assisted (SARME) through cone beam computed tomography (CBCT).Material and Methods Fourteen patients were submitted to SARME through subtotal Le Fort I osteotomy. Both the opening pattern and the mean bone density at midpalatal suture area to evaluate bone formation were assessed pre- and post-operatively (15, 60 and 180 days) through CBCT.Results Type I opening pattern (from anterior to posterior nasal spine) occurred in 12 subjects while type II opening pattern (from anterior nasal spine to transverse palatine suture) occurred in 2 individuals. The 180-day postoperative mean (PO 180) of bone density value was 49.9% of the preoperative mean (Pre) value.Conclusions The opening pattern of midpalatal suture is more related to patients' age (23.9 years in type I and 33.5 years in type II) and surgical technique. It was not possible to observe complete bone formation at midpalatal suture area at the ending of the retention period studied (180 days).

Effects of strontium ranelate on bone formation in the mid-palatal suture after rapid maxillary expansion

BACKGROUND

The aim of this experimental study was to investigate the effects of strontium ranelate on bone regeneration in the mid-palatal suture in response to rapid maxillary expansion (RME).

METHODS

Thirty-six male 6-week-old Wistar rats were randomly divided into three groups, ie, an expansion only (EO) group, an expansion plus strontium ranelate (SE) group, and a control group. An orthodontic appliance was set between the right and left upper molars of rats with an initial expansive force of 0.98 N. Rats in the SE group were administered strontium ranelate (600 mg/kg body weight) and then euthanized in batches on days 4, 7, and 10. Morphological changes in the mid-palatal suture were investigated using micro-computed tomography and hematoxylin and eosin staining after RME. Bone morphogenetic protein-2 expression in the suture was also examined to evaluate bone formation in the mid-palatal suture. Image-Pro Plus software was then used to determine the mean optical density of the immunohistochemical images. Analysis of variance was used for statistical evaluation at the P<0.05 level.

RESULTS

With expansive force, the mid-palatal suture was expanded, but there was no statistically significant difference (P>0.05) between the SE and EO groups. The bone volume of the suture decreased after RME, but was higher in the SE group than in the EO group on days 7 and 10. Further, expression of bone morphogenetic protein-2 in the SE group was higher than in the other two groups (P<0.05).

CONCLUSION

Strontium ranelate may hasten new bone formation in the expanded mid-palatal suture, which may be therapeutically beneficial in prevention of relapse and shortening the retention period after RME.

Ultrasonography in the evaluation of the mid-palatal suture in rapid palatal expansion

OBJECTIVES

Orthodontists usually evaluate the mid-palatal sutural opening with occlusal radiography. The purpose of this article is to evaluate the sutural opening with ultrasonography (USG) in a series of patients undergoing rapid palatal expansion (RPE).

METHODS

The study included 87 USG images and 87 occlusal radiographs from 29 healthy patients (mean age, 13.9 years; range, 11-20 years; boys, 12; girls, 17) who required RPE treatment. The sutural opening was assessed with USG, and the amount of sutural expansion as mesiodistal length was measured immediately after appliance practice (T0), 10 turns (T1) and 20 turns (T2) during the expansion period. Sutural expansion evaluated by occlusal radiographs was scored at every stage. Measurements obtained by USG and scores observed in the occlusal radiographs were compared by non-parametric Kendall's tau test.

RESULTS

Both USG and radiographic images revealed normal anatomical structure during pre-expansion (stage T0). On USG, sutural expansion was seen in 19 patients at stage T1. There was no expansion at this stage in ten patients. At stage T2, on USG and radiography, an increase in the amount of expansion was observed in 19 patients with sutural expansion at stage T1 and sutural expansion was observed in 5 patients without sutural expansion at stage T1. No expansion was observed at both stages T1 and T2 in five patients. USG measurements and occlusal scores in both T1 and T2 turns showed statistically significant correlation (p < 0.001).

CONCLUSIONS

The results indicate that USG might be a useful method to assess mid-palatal sutural opening in patients undergoing RPE.

Short-term and long-term stability of surgically assisted rapid palatal expansion revisited

INTRODUCTION

The purpose of this article is to present further longitudinal data for short-term and long-term stability, following up our previous article in the surgery literature with a larger sample and 2 years of stability data.

METHODS

Data from 38 patients enrolled in this prospective study were collected before treatment, at maximum expansion, at removal of the expander 6 months later, before any second surgical phase, at the end of orthodontic treatment, and at the 2-year follow-up, by using posteroanterior cephalograms and dental casts.

RESULTS

With surgically assisted rapid palatal expansion (SARPE), the mean maximum expansion at the first molar was 7.60 ± 1.57 mm, and the mean relapse was 1.83 ± 1.83 mm (24%). Modest relapse after completion of treatment was not statistically significant for all teeth except for the maxillary first molar (0.99 ± 1.1 mm). A significant relationship (P < 0.0001) was observed between the amount of relapse after SARPE and the posttreatment observation. At maximum, a skeletal expansion of 3.58 ± 1.63 mm was obtained, and this was stable.

CONCLUSIONS

Skeletal changes with SARPE were modest but stable. Relapse in dental expansion was almost totally attributed to lingual movement of the posterior teeth; 64% of the patients had more than 2 mm of dental changes. Phase 2 surgery did not affect dental relapse.

Effect of low-level laser therapy (GaAlAs) on bone regeneration in midpalatal anterior suture after surgically assisted rapid maxillary expansion

OBJECTIVE

The aim of this study was to evaluate the effects of laser therapy on bone regeneration in the midpalatal anterior suture (MPAS) after surgically assisted rapid maxillary expansion (SARME).

METHODS

Thirteen patients aged between 18 and 33 years old with maxillary transverse deficiency (> or =7.0 mm) were evaluated. All patients underwent subtotal Le Fort I osteotomy with separation of the pterygomaxillary suture with the use of Hyrax expander, and were divided into 2 groups: control group (n = 6) and laser group (n = 7). A GaAlAs laser (P = 100 mW, lambda = 830 nm, Ø = 0.06 cm(2)) was used. The laser was applied in 8 treatment sessions with intervals of 48 hours. Each treatment session consisted of laser applications, per point (E = 8.4J, ED = 140J/cm(2)), at 3 points on the MPAS, and total dose of E = 25.2 J, ED = 420 J/cm(2). Digital radiographs were taken before the surgical procedure and at 1-, 2-, 3-, 4-, and 7-month follow-up visits. Optical density analysis of the regenerated bone was performed using Adobe Photoshop 8.0 software.

RESULTS

Bone regeneration associated with the use of laser after SARME showed a statistically significant difference. A higher mineralization rate was found in the laser group (26.3%, P < .001) than the control group.

CONCLUSION

Low-level laser irradiation (GaAlAs) accelerates bone regeneration in MPAS after SARME. However, the optical density measurements after 7 months of follow-up were lower in comparison with the preoperative measurements.

Classification of midpalatal suture opening after surgically assisted rapid maxillary expansion using computed tomography

OBJECTIVE

The aim of this study was to classify the opening of the midpalatal suture (MPS) after surgically assisted rapid maxillary expansion (SARME) with disjunction of the pterygomaxillary suture through computed tomography (CT) analysis.

STUDY DESIGN

Seventy adults with bilateral transverse deficiency of the maxilla underwent SARME with pterygomaxillary disjunction. Seventy tomographies were performed before the surgery and 70 were performed after the final activation. The Hass appliance was used in 29 patients and Hyrax in 41 patients. The MPS opening was classified into 2 types: type I, total MPS opening from the anterior nasal spine to the posterior nasal spine, and type II, total MPS opening from the anterior nasal spine to the transverse palatine suture, with partial or nonexistent opening posterior to transverse palatine suture.

RESULTS

Type I opening was observed in 22 patients (31.5%), and type II opening in 48 patients (68.5%). In 5 cases, the opening posterior to the transverse palatine suture was paramedian.

CONCLUSION

Computed tomography allows the evaluation and classification of midpalatal suture openings after SARME with pterygomaxillary disjunction in type I (total) and type II (partial) MPS openings.

Reliability of traditional cephalometric landmarks as seen in three-dimensional analysis in maxillary expansion treatments

OBJECTIVE

To evaluate intra-examiner and inter-examiner reliability of 3D CBCT-generated landmarks previously used in traditional 2D cephalometry.

MATERIALS AND METHODS

Twenty-four CBCTs NewTom 3G (Aperio Services, Verona, Italy) were randomly selected from patients participating in a clinical trial involving maxillary expansion treatments. The principal investigator located the landmarks five times, and four other investigators located the same landmarks once. Intra-examiner and inter-examiner reliability values were determined using intraclass correlation coefficients (ICCs). To assist in interpretation of the clinical significance of landmark identification differences, average mean differences for x, y, and z landmark coordinates were determined from the repeated assessments. Landmarks then were separated into groups with respect to the region they represented and then were compared via repeated measures ANOVA and multiple comparisons via Bonferroni corrected alpha.

RESULTS

Intra-examiner and inter-examiner reliability for x, y, and z coordinates for all landmarks were acceptable, all being greater than 0.80. Most of the mean measurement differences obtained from trials within the principal investigator in all three axes were less than 1.5 mm. Inter-examiner mean measurement differences generally were larger than the intra-examiner differences.

CONCLUSIONS

Based on this, the best landmarks for use in verifying expansion treatment results are Ekm, buccal surface, and apexes of upper molars, upper premolars and upper canines, and buccal surfaces of lower molars and lower canines. Foramen Spinosum, ELSA, Auditory External Meatus, and Dorsum Foramen Magnum demonstrated adequate reliability for determining a standardized reference system.

Effects of surgically assisted rapid maxillary expansion on nasal dimensions using acoustic rhinometry

OBJECTIVE

The objective of this study was to evaluate the effects of surgically assisted rapid maxillary expansion (SARME) on nasal dimensions using acoustic rhinometry.

STUDY DESIGN

Twenty-seven patients ranging in age from 18 to 53 years were evaluated as having a maxillary transverse deficiency larger than 7 mm, a bilateral cross-bite, and no evidence of nasal obstruction. All patients underwent evaluation of the nasal cavity by acoustic rhinometry both before and 6 months after SARME. The Wilcoxon test was used to evaluate minor cross-sectional areas (MCA) and the nasal volume of the right and left nasal cavities, and these parameters were measured with and without the application of topical nasal decongestant before and after SARME.

RESULTS

In comparison with preoperative measurements, minor cross-sectional areas and nasal volumes were significantly larger after SARME. There was a statistically significant difference associated with the use of nasal decongestant; the minor cross-sectional areas and nasal volume of the right and left nasal cavities were smaller when nasal decongestants were not used.

CONCLUSIONS

Surgically assisted rapid maxillary expansion increases the minor cross-sectional areas and volume of the nasal cavities. Acoustic rhinometry is an objective method for evaluating the geometry of the nasal cavity in patients with transverse maxillary deficiency.