Cone-Beam Computed Tomographic Comparison of Surgically Assisted Rapid Palatal Expansion and Multipiece Le Fort I Osteotomy

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.

Effect of different palatal expanders with miniscrews in surgically assisted rapid palatal expansion: A non-linear finite element analysis

INTRODUCTION

Surgically assisted rapid palatal expansion (SARPE) has been the treatment of choice in subjects presenting skeletally mature sutures.

OBJECTIVE

The purpose of this study was to analyze stress distribution and displacement of the craniofacial and dentoalveolar structures resulting from three types of palatal expanders with surgical assistance using a non-linear finite element analysis.

MATERIAL AND METHODS

Three different palatal expanders were designed: Model-I (tooth-bone-borne type containing four miniscrews), Model-II (tooth-bone-borne type containing two miniscrews), and Model-III (bone-borne type containing four miniscrews). A Le Fort I osteotomy was performed, and a total of 5.0 mm palatal expansion was simulated. Nonlinear analysis (three theory) method (geometric nonlinear theory, nonlinear contact theory, and nonlinear material methods) was used to evaluate stress and displacement of several craniofacial and dentoalveolar structures.

RESULTS

Regardless of the maxillary expander device type, surgically assisted rapid palatal expansion produces greater anterior maxillary expansion than posterior (ANS ranged from 2.675 mm to 3.444 mm, and PNS ranged from 0.522 mm to 1.721 mm); Model-I showed more parallel midpalatal suture opening pattern - PNS/ANS equal to 54%. In regards to ANS, Model-II (1.159 mm) and Model-III (1.000 mm) presented larger downward displacement than Model-I (0.343 mm). PNS displaced anteriorly more than ANS for all devices; Model-III presented the largest amount of forward displacement for PNS (1.147 mm) and ANS (1.064 mm). All three type of expanders showed similar dental displacement, and minimal craniofacial sutures separation. As expected, different maxillary expander designs produce different primary areas and levels of stresses (the bone-borne expander presented minimal stress at the teeth and the tooth-bone-borne expander with two miniscrews presented the highest).

CONCLUSIONS

Based on this finite element method/finite element analysis, the results showed that different maxillary expander designs produce different primary areas and levels of stresses, minimal displacement of the craniofacial sutures, and different skeletal V-shape expansion.

Stability of maxillary expansion osteotomy using patient-specific fixation implants without necessitating removable appliances: a retrospective analysis

OBJECTIVE

This study aimed to evaluate the long-term stability of surgical maxillary expansion using patient-specific fixation implants (PSFIs) without intraoral retention.

MATERIALS AND METHODS

Fifteen patients who had undergone segmented Le Fort I osteotomy and PSFIs with available preoperative (t0) early (t1) and 1-year follow-up computed tomography (CT) scans (t2) were evaluated. The early and 1-year 3D models were superimposed to transfer the bony landmarks; the distances between each pair of landmarks at the different time points were then measured. The distances between the canines and second molars were also measured directly on the CT scans.

RESULTS

The achieved maxillary expansions ranged from a median of 4.39 (2.00-6.27) mm at the greater palatine foramina to a median of 2.14 (1.56-2 > 83) mm at the canine level of the palatal bone. One year postoperatively, the changes in skeletal diameters ranged from a median of - 0.53 (- 1.65 to 0.41) mm at the greater palatine foramina (p = 0.12) to 0.17 (- 0.09 to 0.32) mm at the canine level of the palatal bone (p = 0.56). Changes in dental arch diameters ranged from a median of - 0.6 (- 2 to 0.00) mm between the second molars to - 1.3 (- 1.8 to - 0.25) mm between the canines (P < 0.05).

CONCLUSION

This study showed the stability of maxillary expansion osteotomy using PSFIs, even without postoperative intraoral retention.

CLINICAL RELEVANCE

PSFIs are a reliable method for the surgical treatment of transverse maxillary discrepancy. PFSIs are easy-to-use and improve surgical accuracy.

Factors related to microimplant-assisted rapid palatal expansion in teenagers and young adults: A cone-beam computed tomography study

INTRODUCTION

For patients with maxillary transverse deficiency, selecting an appropriate therapeutic method is important for the treatment effect and prognosis. Our study aimed to explore factors related to microimplant-assisted rapid palatal expansion (MARPE) in teenagers and young adults using cone-beam computed tomography.

METHODS

Twenty-five patients who underwent MARPE were included in this retrospective study from February 2014 to June 2019. Midpalatal suture density (MPSD) ratio, midpalatal suture maturation (MPSM), bone effect, dentoalveolar effect, and dental effect in maxillary first molar were evaluated using cone-beam computed tomography. Spearman correlation analysis was used to analyze the correlation between the MPSD ratio, MPSM, age, and the expansion amount generated by MARPE.

RESULTS

Twenty-five patients (mean age, 19.84 ± 3.96 years; range, 15-29 years) with maxillary transverse deficiency were analyzed. Age was negatively correlated with bone expansion, alveolar expansion, and alveolar change (all P <0.05). There was a negative correlation between MPSM and nasal cavity variation, bone expansion, and alveolar change (all P <0.05). The bone expansion was negatively correlated with MPSD ratio 3 (r = -0.417; P <0.05) and MPSD ratio 4 (all P <0.05).

CONCLUSIONS

Age, MPSM, and MPSD ratio were significantly related to the MARPE effect. Age, MPSM, and MPSD ratio should be considered when choosing MARPE.

Accuracy of Segmented Le Fort I Osteotomy with Virtual Planning in Orthognathic Surgery Using Patient-Specific Implants: A Case Series

Background: When maxillary transversal expansion is needed, two protocols of treatment can be used: a maxillary orthodontic expansion followed by a classical bimaxillary osteotomy or a bimaxillary osteotomy with maxillary segmentation. The aim of this study was to assess the accuracy of segmented Le Fort I osteotomy using computer-aided orthognathic surgery and patient-specific titanium plates in patients who underwent a bimaxillary osteotomy for occlusal trouble with maxillary transversal insufficiencies. Methods: A virtual simulation of a Le Fort I osteotomy with maxillary segmentation, a sagittal split ramus osteotomy, and genioplasty (if needed) was conducted on a preoperative three-dimensional (3D) model of each patient’s skull using ProPlan CMF 3.0 software (Materialise, Leuven, Belgium). Computer-assisted osteotomy saw-and-drill guides and patient-specific implants (PSIs, titanium plates) were produced and used during the surgery. We chose to focus on the maxillary repositioning accuracy by comparing the preoperative virtual surgical planning and the postoperative 3D outcome skulls using surface superimpositions and 13 standard dental and bone landmarks. Errors between these preoperative and postoperative landmarks were calculated and compared to discover if segmental maxillary repositioning using PSIs was accurate enough to be safely used to treat transversal insufficiencies. Results: A total of 22 consecutive patients—15 females and 7 males, with a mean age of 27.4 years—who underwent bimaxillary computer-assisted orthognathic surgery with maxillary segmentation were enrolled in the study. All patients presented with occlusion trouble, 13 with Class III malocclusions (59%) and 9 (41%) with Class II malocclusions. A quantitative analysis revealed that, overall, the mean absolute discrepancies for the x-axis (transversal dimension), y-axis (anterior−posterior dimensions), and z-axis (vertical dimension) were 0.59 mm, 0.74 mm, and 0.56 mm, respectively. The total error rate of maxillary repositioning was 0.62 mm between the postoperative cone-beam computed tomography (CBCT) and the preoperatively planned 3D skull. According to the literature, precision in maxilla repositioning is defined by an error rate (clinically relevant) at each landmark of <2 mm and a total error of <2 mm for each patient. Conclusions: A high degree of accuracy between the virtual plan and the postoperative result was observed.

Alveolar defects before and after surgically assisted rapid palatal expansion (SARPE): a CBCT assessment

INTRODUCTION

Surgically Assisted Rapid Palatal Expansion (SARPE) promote maxillary expansion in skeletally mature patients. This technique is effective; however, some side effects are still unknown.

OBJECTIVES

evaluate the presence of alveolar defects (dehiscences and fenestrations) in patients submitted to the SARPE. The null hypothesis tested was: SARPE does not influence the number of dehiscences and fenestrationss.

METHODS

A retrospective quasi-experiment study of a convenience sample of 279 maxillary teeth, in 29 patients evaluated with Cone Beam Computed Tomography (CBCT) at T1 (before SARPE), T2 (after expansion) and T3 (after retention), was performed. The examined teeth were: canines, first and second premolars, first and second molars. in axial, coronal, and cross-sectional views. The evaluations involved viewing slices from mesial to distal of the buccal roots.

RESULTS

All statistical analyses were performed using SAS 9.3 and SUDAAN softwares. Alpha used in the study was 0.05. Alveolar defects increased statistically from T1 (69.0%) to T2 (96.5%) and T3 (100%). Dehiscences increased 195% (Relative Risk 2.95) at the end of expansion (T2). After retention (T3), individuals were on average 4.34 times more likely to develop dehiscences (334% increase). Fenestrations did not increase from T1 to T2 (p = 0.0162, 7.9%) and decreased from T2 to T3 (p = 0.0259, 4.3%). Presence of fenestrations at T1 was a significant predictor for the development of dehiscences in T2 and T3. Dehiscences increased significantly in all teeth, except second molars.

CONCLUSION

The null hypothesis was rejected. After SARPE the number of dehiscences increased and fenestrations decreased. Previous alveolar defects were predictor for dehiscences after SARPE.

Reliability of Anterior Nasal Spine as a Reference Point After LeFort I Surgery Using Three-Dimensional Analysis

ABSTRACT

To evaluate the stability of maxilla following orthognathic surgery, it is necessary to consider the positional change of various landmarks according to bone remodeling of the maxilla. This study aimed to evaluate the stability of the anterior nasal spine (ANS) as a reliable landmark after orthognathic surgery. Forty-seven patients with skeletal class III malocclusion who underwent bimaxillary orthognathic surgery were included. Skeletal changes were measured using cone-beam computerized tomography at 3 time points: preoperative (T0), 1-month postoperative (T1), and 12-month postoperative (T2). Linear changes of the 6 landmark points of the maxilla were measured in 3 directions: anteroposterior, vertical, and transverse. The data were analyzed with paired t tests, independent t tests, and multiple regression analysis. At 12-month postoperatively, the ANS showed mean (standard deviation) 1.23 (1.07) mm posterior movement (P = 0.00), while other landmarks did not show positional changes, implying bony resorption of ANS. Multiple regression test showed surgical forward movements of ANS (T1-0) affect the postoperative backward changes (β = -.05, P < 0.05). There was a negative correlation between the surgical movement and postoperative change of ANS by Pearson correlation test (r = -0.38, P < 0.05). The ANS is not a reliable measurement point in three-dimensional superimposition after orthognathic surgery. Therefore, in studying the stability and positional change pattern after LeFort I surgery, it is not recommended to use ANS as a reference point, as changes can occur in the measurement point itself.

Surgically assisted rapid palatal expansion (SARPE): three-dimensional superimposition on cranial base

OBJECTIVES

To evaluate dental and skeletal changes caused by surgically assisted rapid palatal expansion (SARPE) using the superimposition of three-dimensional cone-beam computed tomography (CBCT) images on the cranial base.

MATERIAL AND METHODS

This is a retrospective quasi-experiment before-and-after study using a convenience sample. Twenty-four adult patients (13 male and 11 female) were evaluated before SARPE (T0), immediately after expansion (T1), and after 6 months of retention (T2). CBCT scans were superimposed on the anterior cranial base using voxel-based registration. Measurements from different reference points were used for comparisons between times.

RESULTS

At T1, all teeth had significant buccal tipping. At T2, most teeth remained in the same position as at T1, except the first premolar and the first molar, whose buccal roots moved slightly. The amount of bony expansion was 65 to 70% of the amount of tooth movement. The A point and maxillary incisors moved anteriorly from T0 to T1 and T2 (p < 0.0001). Inter-nasal distance had increased significantly at T1 (p < 0.0001) and remained stable at T2 (p = 0.478). No expansion was achieved at the zygomatic arch (p = 0.114).

CONCLUSION

SARPE promoted substantial buccal tipping of posterior teeth and some bone displacement; it also moved the maxilla and teeth forward and increased nasal width.

CLINICAL RELEVANCE

No other clinical studies have evaluated dental and skeletal changes caused by SARPE using superimposition of 3D CBCT images on the cranial base. This study findings may help clinical dentists plan treatments using safe and reliable information.

Three dimensional assessment of segmented Le Fort I osteotomy planning and follow-up: A validation study

OBJECTIVES

The planning accuracy and stability during follow-up of segmented Le Fort I osteotomy, often evaluated using 2D cephalometry and dental cast analysis, is controversial. The aim of this study is to develop and validate a 3D semi-automatic, voxel-based registration assessment protocol to evaluate planning accuracy and stability of segmented Le Fort I osteotomy with individualization of the maxillary segments.

METHODS

Preoperative, immediate postoperative and six months postoperative CBCT images were used to evaluate accuracy and stability of the individual segments in 20 patients (13 female; 7 male) who underwent segmented Le Fort I osteotomy. Three translational (left/right, intrusion/extrusion, anterior/posterior) and three rotational (pitch, roll, yaw) dimensions were calculated for each maxillary segment by means of a user-friendly module. Inter- and intra-observer Inter Class Coefficient (ICC) and mean absolute difference (MAD) were calculated.

RESULTS

The inter- and intra-observer reliability ICC varied between 0.93 and 0.99 for the translational and rotational accuracy and stability assessments, indicating excellent reliability. The MAD ranged between 0.21 mm and 0.32 mm for the translational error and between 0.6° and 0.9° for the rotational dimension.

CONCLUSIONS

The 3D assessment protocol for accuracy of segmented Le Fort I planning and short-term follow-up, proved to have high reliability with only a small margin of error.

CLINICAL SIGNIFICANCE

The proposed 3D assessment protocol allows future in-depth analysis of segmented Le Fort I osteotomy and might implicate future improvement where necessary.

Complications Following One-Stage Versus Two-Stage Surgical Treatment of Transverse Maxillary Hypoplasia

PURPOSE

Contemporary literature suggests a similar transverse stability of a surgical-assisted rapid palatal expansion and a segmented Le Fort I osteotomy. The aim of this study was to compare postoperative complications of 1-stage (segmental maxillary osteotomy) and 2-stage (surgical-assisted rapid palatal expansion followed by Le Fort I osteotomy) treated patients to determine the preferred treatment strategy.

MATERIALS AND METHODS

This retrospective study included 74 consecutive patients (age range: 14 - 57 years; 36 males, 38 females) with a moderate transverse maxillary hypoplasia: 32 patients were treated in a 1-stage protocol and 42 in a 2-stage protocol with a postoperative follow-up of at least 1 year. Dental complications such as loss of teeth, gingival dehiscence, periodontal bone loss, apical root resorption, and surgical complications such as pain, hemorrhage, altered neurosensitivity, wound infection, aseptic necrosis were analyzed. Univariate analysis consisted of a generalized linear model with logit link or Fisher exact test.

RESULTS

No significant difference was found for group characteristics except for longer orthodontic treatment time in the 2-stage group. Incidence and severity of complications were comparable for the 1-stage and 2-stage patients. Only overall pain was significantly greater in the 2-stage patient group (P = .038).

CONCLUSIONS

Considering a similar complication rate and transversal stability, the choice between 1-stage and 2-stage approach for patients with a moderate transverse maxillary hypoplasia should be patient specific.

The stability of surgically assisted rapid maxillary expansion (SARME): A systematic review

BACKGROUND

This systematic review was conducted to determine the stability of surgically assisted rapid maxillary expansion (SARME) for correction of transverse maxillary deficiency, the effect of distractor type (tooth-borne vs. bone-borne) and the influence of a retainer on post-expansion stability.

METHODS

The review was conducted applying the PICO criteria. Electronic database searches of published literature (MEDLINE via PubMed), Ovid via MEDLINE, the Cochrane Oral Health Group's Trial Register, Cochrane Central Register of Controlled Trials, (CENTRAL) and unpublished literature were accessed until January 2019. Search terms included SARME, 'stability', 'relapse', 'surgery', 'expansion' and 'maxillary expansion'.

RESULTS

Five hundred and ten studies were identified overall and 15 studies were included (3 RCTs, 2 prospective & 10 retrospective) following initial screening and data extraction of full texts. The quality of evidence was assessed using the Cochrane Risk of Bias tool for RCTs and the Newcastle-Ottawa Scale for prospective & retrospective studies. The heterogeneity of the retrieved articles prohibited quantitative analysis. Overall, the studies were either of high risk of bias or low quality. Qualitative analysis reveals SARPE to achieve expansion at the inter-canine region of 4-for inter 6 mm, inter-molar region of 6-8.9 mm, and skeletal level of 2.3-3.1 mm with relapse rates in the region of 0.1-2.3 mm (inter-canine), 0.2-3 mm (inter-molar) and 0-1.8 mm (skeletal) reported.

CONCLUSION

Qualitative evaluation suggests SARPE results in significant expansion at the dental and skeletal level and that this appears to be stable. Existing literature is equivocal on the clinical benefits of a retention device or distractor type (bone-borne vs. tooth borne) on stability. This review has unearthed the need for high quality prospective RCTs to fully understand the stability of SARME, particularly with relation to varying distractor types and use of retention devices. As such, the inferences drawn should be considered with some discretion based on the quality of the available evidence.

Can palatal splint improve stability of segmental Le Fort I osteotomies?

OBJECTIVES

The purpose of this study was to evaluate the influence of a palatal splint on stability in multi-segment maxillary osteotomies.

SETTING AND SAMPLE POPULATION

Retrospective series of fifty-one adult patients, consecutively operated with bilateral sagittal split osteotomy (BSSO) and three-piece maxillary osteotomies, divided according to the use of a palatal splint (Group 1, n = 30) or no palatal splint (Group 2, n = 21).

MATERIALS AND METHODS

Maxillary surgical casts (T1) and post-retention casts (T2), taken at least six months after discontinuation of orthodontic retention, were digitized (MicroScribe-3DX), measured and compared. Fifty-one landmarks were identified on the maxillary, transverse dimension changes and arch length were calculated. Longitudinal changes in all measurements were assessed by t test.

RESULTS

Post-surgical transverse instability in group 1 ranged from 0.3 ± 0.4 to -1.3 ± 0.2 mm and was statistically significantly smaller than in group 2 that ranged from -1.0 ± 0.3 to -2.5 ± 0.5 mm.

CONCLUSIONS

The use of a palatal splint after segmental Le Fort I maxillary osteotomy improved transverse stability in the posterior region. The post-surgical transverse instability occurred only between canine gingival points and thus suggesting no clinical relevance.

Surgical Treatment Selection in Adult Class III Patients With Maxillary Transverse Deficiency

The purpose of this study was to investigate the frequency of three commonly used treatments for skeletal class III malocclusion with maxillary transverse deficiency (MTD) (SCM) patients in East Asian, to find a quantitative method for precise discrepancy evaluation, and to find other potential indicators for treatment selection. A total of 239 adult SCM patients were divided into3 groups according to treatments.Dentofacial features were measured and the initial skeletal discrepancy was evaluated with computer-aided surgical simulation (CASS). Relationship between the degree of skeletal transverse discrepancy (STD) and other dentofacial features were analyzed by Spearman's rank correlation. The STD in East Asian could be quantitatively grouped as: mild (<4 mm), moderate (4-8 mm), and severe (>8 mm). Most patients (81%) could be diagnosed with mild STD, and were treated without surgical expansion. The upper first molars inclination, the required relative movement and the required maxillary movement were correlated to the degree of STD. The conventional orthodontic and orthognathic treatment without surgical expansion is the most frequent choice for East Asian SCM adults. CASS facilitated analysis is useful in an accurate MTD evaluation. Some dentofacial features were closely correlated to STD, and thus were helpful for the treatment selection.

Changes of the upper airway and bone in microimplant-assisted rapid palatal expansion: A cone-beam computed tomography (CBCT) study

OBJECTIVE

To evaluate the changes of maxillary expansion and upper airway structure after microimplant assisted rapid palatal expansion (MARPE) using cone-beam computed tomography (CBCT).

METHODS

This retrospective study included 19 subjects (15 females and 4 males) aged 15-29 years old (mean, 19.95±4.39 years) with maxillary transverse deficiency treated with MARPE. CBCT was performed at the initial diagnosis and 3 months after MARPE treatment. Measurements were taken to evaluate the amount of total expansion, skeletal expansion, and dental expansion at the maxillary first premolar (P1), second premolar (P2), first molar (M1), second molar (M2) regions and upper airway changes.

RESULTS

After MARPE treatment, the maxillary skeletal base expansion, skeletal expansion, alveolar expansion and dental expansion were achieved at the P1, P2, M1, M2 region. The nasopharyngeal volume significantly increased 8.48% after MARPE treatment compared with that before the treatment (P < 0.05). The change of nasal lateral width (NLW) was also significantly different before and after MARPE (P < 0.05). However, there were no statistically significant change in the oropharyngeal, palatopharyngeal, glossopharyngeal and airway total volume (all P > 0.05).

CONCLUSIONS

MARPE can produce more transverse bone expansion, relieve maxillary transverse deficiency and improve upper airway ventilation.

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.

Midpalatal suture density ratio: A novel predictor of skeletal response to rapid maxillary expansion

INTRODUCTION

During adolescence, increasing interdigitation of the midpalatal suture increases resistance to rapid maxillary expansion (RME); this decreases its skeletal effect. In this study, we aimed at determining whether a novel measure of midpalatal suture maturity, the midpalatal suture density ratio, can be used as a valid predictor of the skeletal response to RME.

METHODS

The midpalatal suture density ratio, chronologic age, cervical vertebral maturation, and the stage of midpalatal suture maturation were assessed before treatment for 30 patients (ages, 12.9 ± 2.1 years) who underwent RME as part of comprehensive orthodontic treatment. Measurements on cone-beam computed tomography scans were used to determine the proportions of prescribed expansion achieved at the greater palatine foramina, the nasal cavity, and the infraorbital foramina.

RESULTS

There was a statistically significant negative correlation between the midpalatal suture density ratio and both the greater palatine foramina and the infraorbital foramina (r = -0.7877 and -0.3647, respectively; P <0.05). In contrast, chronologic age, cervical vertebral maturation, and stage of midpalatal suture maturation were not significantly correlated to any of the assessed measures of skeletal expansion (r range, -0.2209 to 0.0831; P >0.05).

CONCLUSIONS

The midpalatal suture density ratio has the potential to become a useful clinical predictor of the skeletal response to RME. Conversely, chronologic age, cervical vertebral maturation, and stage of midpalatal suture maturation cannot be considered useful parameters to predict the skeletal effects of RME.

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.

Transverse Expansion and Stability after Segmental Le Fort I Osteotomy versus Surgically Assisted Rapid Maxillary Expansion: a Systematic Review

Objectives

The objective of the present systematic review was to test the hypothesis of no difference in transverse skeletal and dental arch expansion and relapse after segmental Le Fort I osteotomy versus surgically assisted rapid maxillary expansion.

Material and Methods

A MEDLINE (PubMed), Embase and Cochrane library search in combination with a hand-search of relevant journals was conducted by including human studies published in English from January 1, 2000 to June 1, 2016.

Results

The search provided 130 titles and four studies fulfilled the inclusion criteria. All the included studies were characterized by high risk of bias and meta-analysis was not possible due to considerable variation. Both treatment modalities significantly increase the transverse maxillary skeletal and dental arch width. The transverse dental arch expansion and relapse seems to be substantial higher with tooth-borne surgically assisted rapid maxillary expansion compared to segmental Le Fort I osteotomy. The ratio of dental to skeletal relapse was significantly higher in the posterior maxilla with tooth-borne surgically assisted rapid maxillary expansion. Moreover, a parallel opening without segment tilting was observed after segmental Le Fort I osteotomy.

Conclusions

Maxillary transverse deficiency in adults can be treated successfully with both treatment modalities, although surgically assisted rapid maxillary expansion seems more effective when large transverse maxillary skeletal and dental arch expansion is required. However, considering the methodological limitations of the included studies, long-term randomized studies assessing transverse skeletal and dental expansion and relapse with the two treatment modalities are needed before definite conclusions can be provided.