Using Computed Tomography to Evaluate Maxillary Changes After Surgically Assisted Rapid Palatal Expansion

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.

Surgically assisted rapid maxillary expansion: current concepts of minimally invasive approaches

Studies have consistently shown an association of the Le Fort I osteotomy with undesirable adverse events in the nasolabial region, including lengthening and thinning of the upper lip, a reduction in upper vermilion exposure, and nasal base enlargement. Various minimally invasive techniques have been developed based on knowledge collected over recent decades on the aetiopathogenesis of these aesthetic impairments. The common scope of these techniques is to reduce the damage to the facial soft tissues and achieve a sound and spontaneous healing process, avoiding those procedures that are commonly used to counteract undesirable aesthetic changes. This paper provides a summary of the aetiopathogenesis of these adverse events, as well as an overview of current concepts in minimally invasive surgically assisted rapid maxillary expansion (miSARME).

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.

Clinical and CT Scan Evaluation of Outcomes of Modified SARPE Using a Bone-Borne Hyrax Appliance in Unilateral Posterior Crossbite

Objective

The objective of this study was to evaluate, using clinical and computed tomography, outcomes of unilateral SARPE with a bone-borne hyrax appliance in case of unilateral crossbite and to assess the correlations between hyrax appliance opening and post-SARPE skeletal changes.

Materials and Methods

Two patients of unilateral crossbite underwent Unilateral SARPE and post-surgical expansion of maxilla using a bone-borne hyrax appliance. Computed tomography was used to make comparative linear and angular measurements of the anterior, intermediate, and posterior portions of the maxilla. The correlation between maxillary expansion and appliance opening was also investigated.

Results

Significant overall expansion was observed with maximum expansion in the anterior and inferior portions of the maxilla. The degree of appliance opening was significantly greater than that of the skeletal expansion. Comparative CAD measurements showed maximum increase in interdental width at the second premolar level.

Conclusion

The transverse expansion of the maxilla obtained with a bone-borne hyrax is less than uniform. The lack of linear correlation between appliance opening and skeletal expansion is attributable to multiple factors, including those related to the device, the surgical technique, and the craniofacial deformity itself.

Sagittal and Vertical Changes of the Maxilla after Surgically Assisted Rapid Palatal Expansion: A Systematic Review and Meta-Analysis

Surgically assisted rapid palatal expansion (SARPE) is often performed to correct the transverse deficiency in the maxilla for skeletally mature patients. However, there is little consensus on the sagittal and vertical displacement of the maxilla after SARPE. This systematic review aims to analyze the position changes of the maxilla in the sagittal and vertical dimensions after the completion of SARPE. Registered with PROSPERO (registration number: CRD42022312103), this study complied with the 2020 PRISMA guideline and was conducted on 21 January 2023. Original studies were screened from MEDLINE (PubMed), Elsevier (SCOPUS), and Cochrane, and supplemented by hand-searching. Cephalometric changes of skeletal vertical and sagittal measurements were the focus. A fixed-effects model was applied in R for meta-analysis. After applying inclusion and exclusion criteria, seven articles were included in the final review. Four studies had a high risk of bias, and the other three had a medium risk of bias. Meta-analysis revealed that the SNA angle increased by 0.50° ± 0.08° (95% confidence interval, 0.33° to 0.66°), and the SN-PP angle increased by 0.60° ± 0.09° (95% confidence interval, 0.41° to 0.79°) after SARPE. In summary, the maxilla displayed statistically significant forward and clockwise downward movement after SARPE. However, the amounts were small and might not be clinically significant. Due to the high risk of bias of included studies, our results must be taken cautiously. Future studies are needed to discern the effects of direction and angulation of the osteotomies of SARPE on the displacement of the maxilla.

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.

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.

Surgically assisted maxillary expansion with or without pterygoid disjunction alters maxillomandibular positioning

PURPOSE

This study aimed to analyze alterations in mandibular positioning after surgically assisted maxillary expansion (SARME) with and without pterygoid disjunction (PD).

METHODS

Cone-beam computed tomography scans of 24 healthy individuals (18-45 years old) with transverse deficiency, superior to 5 mm, underwent SARME with or without PD. The aspects prospectively assessed were (1) alignment and position of the head (ITK-Snap and 3D Slicer software); (2) McNamara's and Steiner-Tweed-Wits' cephalometric analysis (Dolphin Imaging®); and (3) colorimetric evaluation based on 3D correspondence analysis (3D Slicer software).

RESULTS

A decrease in 1-NA and 1-SN angles as well as an increased occlusal plane in both groups was observed. Superior-inferior and anteroposterior spatial displacements of the chin were statistically significant in the PD group. Altered colorimetric patterns were also observed in the PD group.

CONCLUSIONS

This study found more evident tooth inclination in the group without PD; mandibular alterations were more evident in the PD group. Further studies with 3D analysis are strongly recommended for more comprehensive results.

Assessment of pulp volume changes after surgically assisted rapid palatal expansion

Maxillary transverse deficiency is a common skeletal problem. When the patient is younger, it is treated by rapid palatal expansion by using orthodontic appliances. If this fails or the patient is older, which means skeletal growth is completed, surgically aided rapid palatal expansion (SARPE) becomes necessary. In this technique, after the osteotomies have been made, the two maxillary bones are distracted by tooth-borne device. Since a tooth-borne device will apply the distraction forces on the teeth, the pulp volumes may change. Our aim was to investigate the volume changes of the tooth pulps after SARPE in which a tooth-borne device was used. We scanned our database and included 20 patients (7 males and 13 females) aging between 16 and 30 (mean 19.5±3.97) to this retrospective study. All the patients had undergone SARPE surgeries and they had pre-surgery and postconsolidation cone beam computerized tomography (CBCT) images. All the surgeries had been done in similar ways; all the patients had used similar tooth-borne modified acrylic bonded expansion device. We divided the maxillary teeth into three groups: the incisors, the premolars and the molars. We imported the CBCT images of each patient into 3D Slicer software. We calculated volumes of pulps for all maxillary teeth. We compared volumes with paired t test. Statistical significance level was accepted as P< .05. The devices had been left in place between 83 and 179 days including distraction and consolidation periods (mean 121.35±27.83 days). Amount of the expansions varied between 6.03mm and 11.16mm (mean 7.19±1.18mm). We found a statistically significant decrease of the pulp volumes in incisor, premolar and molar teeth (P<.001) between pre-surgery and postconsolidation periods. When using tooth-borne devices in SARPE, their impacts on teeth pulps should also be considered.

Is There a Significant Difference in Relapse and Complication Rate of Surgically Assisted Rapid Palatal Expansion Using Tooth-Borne, Bone-Borne, and Orthodontic Mini-Implant-Borne Appliances?

PURPOSE

For surgically assisted rapid palatal expansion (SARPE), studies comparing different devices are missing. The aim was to evaluate expansion, relapse, and the complication rates for 3 different appliances.

PATIENTS AND METHODS

In this retrospective cohort study, tooth-borne (TB, n = 29), bone-borne (BB, n = 12), or orthodontic mini-implant (OMI)-borne (n = 13) appliances were used for SARPE in 2 clinical centers. Patients presenting with a maxillary width discrepancy greater than 5 mm were included. Measurements of cast models and radiographs were performed preoperatively, immediately after consolidation, and at 1 year postoperatively. All distances were measured between canines, premolars, and molars. Complications (tooth damage, infection, technical failure) were evaluated. The outcome variables were expansion, relapse, and complications. Type of appliance was selected as predictor variable. Within- and between-group differences regarding expansion, relapse, and complications for the 3 appliances were statistically analyzed.

RESULTS

In 54 patients (aged 28.8 ± 8.6 years), mean expansion (±standard deviation) for the TB, BB, and OMI appliances immediately after consolidation was 5.29 ± 1.39 mm, 5.22 ± 1.72 mm, and 3.81 ± 2.19 mm, respectively, at the dental level, and 5.51 ± 1.40 mm, 4.66 ± 2.03 mm, and 3.51 ± 1.66 mm, respectively, at the bone level. Mean (±standard deviation) relapse for the TB, BB, and OMI appliances at 1 year postoperatively measured 1.44 ± 1.01 mm, 0.76 ± 1.37 mm, and 0.27 ± 1.63 mm, respectively, at the tooth level and 1.19 ± 0.93 mm, 0.71 ± 0.96 mm, and 0.12 ± 1.56 mm, respectively, at the bone level. Analysis of variance and the Tukey test showed significant differences between the TB and OMI appliances for expansion and relapse (P = .034 and P = .024, respectively). The overall complication rate differed significantly (P < .001), with rates of 17.2%, 66.7%, and 15.4% for the TB, BB, and OMI appliances, respectively.

CONCLUSIONS

BB and OMI appliances resulted in less relapse. Owing to the high complication rate, the further use of BB appliances is questionable.

Expansion in the absence of crossbite – rationale and protocol

Transverse maxillomandibular discrepancies are a major component of several malocclusions. Clinically, posterior crossbite is a common and valid indicator of maxillary transverse problems and orthopedic and orthodontic forces are routinely used to correct maxillary transverse deficiency. However, crossbite and transverse discrepancies are not a homologous group but must be viewed as a continuum with varying degree of abnormality. The etiology, diagnostic protocol, rationale, and procedures employed for correcting maxillary transverse discrepancy in the absence of crossbite are discussed in the article.

Evaluation of the stability of maxillary expansion using cone-beam computed tomography after segmental Le Fort I osteotomy in adult patients with skeletal Class III malocclusion

Objective

The aim of this study is to quantitatively evaluate the stability of the skeletal and dental widths using cone-beam computed tomography (CBCT) after segmental Le Fort I osteotomy in adult patients with skeletal Class III malocclusion requiring maxillary expansion.

Methods

In total, 25 and 36 patients with skeletal Class III malocclusion underwent Le Fort I osteotomy (control group) and segmental Le Fort I osteotomy (experimental group), respectively. Coronal CBCT images were used to measure the dental and skeletal widths before (T1) and after (T2) surgery and at the end of treatment (T3). The correlation between the extent of surgery and the amount of relapse in the experimental group was also determined.

Results

In the control group, the dental width exhibited a significant decrease of 0.70 ± 1.28 mm between T3 and T2. In the experimental group, dental and skeletal expansion of 1.83 ± 1.66 and 2.55 ± 1.94 mm, respectively, was observed between T2 and T1. The mean changes in the dental and skeletal widths between T3 and T2 were -1.41 ± 1.98 and -0.67 ± 0.72 mm, respectively. There was a weak correlation between the amount of skeletal expansion during segmental Le Fort I osteotomy and the amount of postoperative skeletal relapse in the experimental group.

Conclusions

Maxillary expansion via segmental Le Fort I osteotomy showed good stability, with a skeletal relapse rate of 26.3% over approximately 12 months. Our results suggest that a greater amount of expansion requires greater efforts for the prevention of relapse.

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.

Diagnostic methods for assessing maxillary skeletal and dental transverse deficiencies: A systematic review

Objective

To evaluate the accuracy and reliability of the diagnostic tools available for assessing maxillary transverse deficiencies.

Methods

An electronic search of three databases was performed from their date of establishment to April 2015, with manual searching of reference lists of relevant articles. Articles were considered for inclusion if they reported the accuracy or reliability of a diagnostic method or evaluation technique for maxillary transverse dimensions in mixed or permanent dentitions. Risk of bias was assessed in the included articles, using the Quality Assessment of Diagnostic Accuracy Studies tool-2.

Results

Nine articles were selected. The studies were heterogeneous, with moderate to low methodological quality, and all had a high risk of bias. Four suggested that the use of arch width prediction indices with dental cast measurements is unreliable for use in diagnosis. Frontal cephalograms derived from cone-beam computed tomography (CBCT) images were reportedly more reliable for assessing intermaxillary transverse discrepancies than posteroanterior cephalograms. Two studies proposed new three-dimensional transverse analyses with CBCT images that were reportedly reliable, but have not been validated for clinical sensitivity or specificity. No studies reported sensitivity, specificity, positive or negative predictive values or likelihood ratios, or ROC curves of the methods for the diagnosis of transverse deficiencies.

Conclusions

Current evidence does not enable solid conclusions to be drawn, owing to a lack of reliable high quality diagnostic studies evaluating maxillary transverse deficiencies. CBCT images are reportedly more reliable for diagnosis, but further validation is required to confirm CBCT's accuracy and diagnostic superiority.

Periodontal and dental effects of surgically assisted rapid maxillary expansion, assessed by using digital study models

OBJECTIVE

The present study assessed the maxillary dental arch changes produced by surgically assisted rapid maxillary expansion (SARME).

METHODS

Dental casts from 18 patients (mean age of 23.3 years) were obtained at treatment onset (T1), three months after SARME (T2) and 6 months after expansion (T3). The casts were scanned in a 3D scanner (D-250, 3Shape, Copenhagen, Denmark). Maxillary dental arch width, dental crown tipping and height were measured and assessed by ANOVA and Tukey's test.

RESULTS

Increased transversal widths from T1 and T2 and the maintenance of these values from T2 and T3 were observed. Buccal teeth tipping also showed statistically significant differences, with an increase in all teeth from T1 to T2 and a decrease from T2 to T3. No statistically significant difference was found for dental crown height, except for left first and second molars, although clinically irrelevant.

CONCLUSION

SARME proved to be an effective and stable procedure, with minimum periodontal hazards.

Transverse changes after surgically assisted rapid palatal expansion

The aim of this retrospective study was to investigate the amount of skeletal and dental expansion in patients submitted to surgically assisted rapid palatal expansion (SARPE). The sample consisted of 21 patients (14 female and seven male) with a mean age of 25.4 years (range 17.4-41.8 years). Postero-anterior (PA) cephalograms were taken pre-expansion (T1), immediately after expansion (T2), and at post-expansion retention of 120 days (T3). SARPE promoted significant transverse skeletal changes, which were maintained from T2 to T3. Dentoalveolar expansion and dental tipping were also observed in the region of the first molars and first premolars; however the net effect at the first molars was significantly less than that at the first premolars. No statistically significant effect on the width of the nasal cavity was observed. The findings indicate that peculiarities inherent to dental effects may influence the clinical options for SARPE. Skeletal expansions with SARPE were significant and stable. Dental changes were different between molars and premolars. The transverse changes after SARPE should be observed for future procedures related to the retention and the completion of orthodontic treatment.

Fat grafts supplemented with adipose-derived stromal cells in the rehabilitation of patients with craniofacial microsomia

BACKGROUND

Although first reports of the clinical use of adipose-derived stromal cells suggest that this approach may be feasible and effective for soft-tissue augmentation, there is a lack of randomized, controlled clinical trials in the literature. Thus, this study aimed to investigate whether a faster protocol for isolation of adipose-derived stromal cells and their use in combination with fat tissue improve the long-term retention of the grafts in patients with craniofacial microsomia.

METHODS

Patients with craniofacial microsomia (n = 14) were grafted either with supplementation of adipose-derived stromal cells (experimental group) or without supplementation of adipose-derived stromal cells (control group). The number of viable cells isolated before and after the supplementation of the grafts was calculated, and these cells were examined for mesenchymal cell surface markers using flow cytometry. Computed tomography was performed to assess both hemifaces preoperatively and at 6 months postoperatively.

RESULTS

The average number of viable cells isolated before and after the supplementation of the grafts was 5.6 × 10 and 9.9 × 10 cells/ml of fat tissue (p = 0.015). Flow cytometric analysis revealed that the adipose-derived stromal cells were positive for mesenchymal cell markers (>95 percent for CD73 and CD105). Surviving fat volume at 6 months was 88 percent for the experimental group and 54 percent for the control group (p = 0.003).

CONCLUSION

These results suggest that this strategy for isolation and supplementation of adipose-derived stromal cells is effective, safe, and superior to conventional lipoinjection for facial recontouring in patients with craniofacial microsomia.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

Periodontal effects of surgically assisted rapid palatal expansion evaluated clinically and with cone-beam computerized tomography: 6-month preliminary results

INTRODUCTION

Transverse maxillary deficiency is frequently observed in patients who seek orthodontic treatment. In skeletally mature patients, transverse maxillary deficiency can be treated with surgically assisted rapid palatal expansion (SARPE). Forces delivered by the expander produce areas of compression in the periodontal ligament, which could lead to alveolar bone resorption and possible changes in the attachment level. The aim of this prospective clinical study was to evaluate the periodontal effects of SARPE by means of a complete clinical evaluation and cone-beam computerized tomography (CBCT) evaluation.

METHODS

The sample included 14 patients (5 males, 9 females), with a mean age of 23.0 ± 1.9 years (range: 16.4 to 39.7 years). All patients were treated using a bonded Hyrax-type expander, and the mean expansion was 9.82 mm (7.5 to 12.0 mm). All patients had a 1-year retention period. CBCT scans were taken, and periodontal charts were completed at time points T0 (initial) and T1 (6 months after expansion).

RESULTS AND DISCUSSION

SARPE seemed to have little detrimental clinical effects on the periodontium. Radiographic data demonstrated statistically significant changes: a significant decrease in the buccal alveolar bone thickness on most teeth, a significant increase in the palatal alveolar bone thickness on most teeth, a decrease in the buccal alveolar crest level of all canines and posterior teeth, and a tendency toward a decrease in the interproximal alveolar crest level on the mesial aspect of both central incisors.

CONCLUSIONS

SARPE seems to have little detrimental effects on the periodontium clinically. However, radiographic data demonstrated some statistically significant changes, which could eventually have a significant clinical impact on the periodontium.

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.

Surgical treatment of maxillary transverse deficiency: retrospective study of 14 patients

INTRODUCTION

The diversity of the proposed techniques in the treatment of maxillary transverse deficiency in adults reflects the conflicting opinions about the primary area of resistance to maxillary expansion in the craniofacial skeleton. In order to evaluate the efficiency of the surgical expansion in which no osteotomies of the pterygomaxillary junction were made, we have carried out a retrospective study with 14 patients with maxillary transverse deficiency, who were treated from 2003 to 2006.

MATERIAL AND METHODS

In the study, models were made prior to and after surgery, and the intercanine and intermolar distances and the improvement of the interocclusal relationships were analyzed. Breathing function and the complications that occurred during and after the surgeries were also analyzed.

RESULTS

All expansions were carried out according to pre-surgical planning so that expansion completely corrected the crossbite, resulting in the desired final occlusion for all patients. Intraoperative complications were limited to one Hyrax appliance deformation. Two patients had minor postoperative complications that included wound dehiscence and pain. Improvements in nasal breathing were observed in all patients that complained of breathing problems prior to the surgery.

CONCLUSION

The satisfactory results obtained turns the surgical protocol described in this study recommended for the treatment of maxillary transverse deficiency in adults. Importantly, we found that pterygomaxillary osteotomy is not essential for maxillary expansion. The morbidity of the procedure was low with fairly minor complications, and surgically assisted rapid maxillary expansion was shown to improve nasal breathing.

Hyrax appliance opening and pattern of skeletal maxillary expansion after surgically assisted rapid palatal expansion: a computed tomography evaluation

OBJECTIVE

The objective of this study was to evaluate, using computed tomography, correlations between Hyrax appliance opening and post-SARPE skeletal changes.

STUDY DESIGN

Fifteen patients underwent SARPE according to a specific protocol and were followed. Linear and angular measurements of the anterior, intermediate, and posterior portions of the maxilla were evaluated. The correlation between maxillary expansion and appliance opening was investigated.

RESULTS

Significant overall expansion was observed. In the anterior and intermediate portions of the maxilla, the increase in maxillary width was greater than that observed in the posterior portion. The degree of appliance opening was significantly greater than that of the skeletal expansion. Also, no linear correlation between appliance opening and regional maxillary expansion was established.

CONCLUSION

The transverse expansion of the maxilla was less than uniform. The lack of linear correlation between appliance opening and skeletal expansion is attributable to multiple factors, including those related to the device, the surgical technique, and the craniofacial deformity itself.

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

Surgically assisted rapid maxillary expansion is the treatment of choice for correcting maxillary transverse deficiency in adults. Traditionally, the appliance for expansion is tooth-borne and tissue-tooth-borne devices (Hyrax and Haas). Although a number clinical and radiographic studies have evaluated the surgically assisted rapid maxillary expansion, only limited information is available to study the transverse movement of the midpalatal suture with computed tomography. Forty adult patients of both sexes, ranging in age from 18 to 38 years, with bilateral transverse maxillary deficiency were operated on. Twenty patients had Hyrax expander, and 20 had Haas expander. Under general anesthesia, subtotal Le Fort I osteotomy was performed including pterygomaxillary dysjunction. The width of the midpalatal suture opening was measured at the anterior edge of the midpalatal suture and at the junction of the midpalatal suture and palatal bones, using computed tomography in axial acquisition, obtained in the preoperative period and immediately after the end of expansion. A digital caliper was used to measure Haas and Hyrax distance on the central jackscrew preoperatively and postoperatively. The proportion between the midpalatal suture expansion and the amount of expansion on the jackscrew was evaluated. The mean of midpalatal suture opening and screw opening for Haas group was 5.19 and 8.78 mm, and for the Hyrax group, 5.85 and 8.51 mm, respectively. Both groups showed parallel-shaped separation of the midpalatal opening with no significant difference in the anterior and posterior portion. Midpalatal/jackscrews opening proportion was greater in the Hyrax group (69,2%) than in the Haas group (60%).