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

Three-dimensional assessment of the maxilla after modified surgically assisted rapid expansion: a retrospective study

OBJECTIVE

This retrospective study aims to assess the three-dimensional dentoskeletal effects and median palatal suture opening pattern in patients undergoing modified surgically assisted maxillary rapid expansion (SARME) without pterygoid plate detachment.

METHODS

Twenty-eight patients submitted to modified SARME between 2009 and 2016 were retrospectively evaluated through cone-beam computed tomography (CBCT). Dental and skeletal measurements were taken at three different operative periods (before the expansion - T0; at the end of the activation of the Hyrax device - T1; and six months after the immobilization of the device - T2). Statistical analyses, including ANOVA and Pearson's correlation coefficient, were performed using SPSS software.

RESULTS

SARME demonstrated significant transverse maxillary expansion (with an average of 6.05 mm) with a greater impact in the anterior region. Dental measurements, including canine and molar distances, exhibited significant changes over the operative periods. Bone measurements (ANS and PNS) presented small but significant alterations, including a slight inferior displacement of ANS during device activation. The nasal floor width increased, followed by a width reduction after immobilization. The median palatal suture predominantly exhibited a Type II (V-shaped) opening.

CONCLUSION

The modified SARME presented a transversal direction increase and a super-lower skeletal displacement, with the anterior region being more affected than the posterior region. There was no change in the anteroposterior direction of the maxilla. Additionally, there was an increase in the linear dental measurements and a decrease in the angular measurement, with a positive correlation between the amount of posterior bone expansion and molar expansion as a result of the treatment in the analyzed period.

Dehiscence and fenestration of skeletal Class III malocclusions with different vertical growth patterns in the anterior region: A cone-beam computed tomography study

INTRODUCTION

This study aimed to evaluate the incidence and distribution of alveolar bone dehiscence and fenestration in skeletal Class III malocclusions with different vertical growth patterns in the anterior region using cone-beam computed tomography (CBCT).

METHODS

In this retrospective study, 84 patients with skeletal Class III malocclusions who underwent CBCT were selected. This study included 28 patients with hypodivergence (mean age, 22.9 ± 3.9 years), 28 with normodivergence (mean age, 21.0 ± 3.0 years), and 28 with hyperdivergence (mean age, 21.0 ± 3.7 years). Teeth in the anterior region were examined using CBCT to detect dehiscence and fenestration. The incidences of dehiscence and fenestration in the anterior teeth region were recorded, and statistical analysis was conducted using SPSS software (version 25.0, IBM, Armonk, NY).

RESULTS

Among the patients with skeletal Class III malocclusions, dehiscence and fenestration were prone to occur in the mandible. Dehiscence and fenestration were more prevalent in patients with hyperdivergence compared with in patients with hypodivergence and normodivergence.

CONCLUSIONS

Dehiscence and fenestration are prevalent among patients with skeletal Class III malocclusion. Furthermore, the occurrence of alveolar bone defects is higher in patients with hyperdivergence.

Pattern of microimplant displacement during maxillary skeletal expander treatment: A cone-beam computed tomography study

Objective

To analyze the microimplant (MI) displacement pattern on treatment with a maxillary skeletal expander (MSE) using cone-beam computed tomography (CBCT).

Methods

Thirty-nine participants (12 males and 27 females; mean age, 18.2 ± 4.2 years) were treated successfully with the MSE II appliance. Their pre- and post-expansion CBCT data were superimposed. The pre- and post-expansion anterior and posterior inter-MI angles, neck and apical inter-MI distance, plate angle, palatal bone thickness at the MI positions, and suture opening at the MI positions were measured and compared.

Results

The jackscrew plate was slightly bent in both anterior and posterior areas. There was no significant difference in the extent of suture opening between the anterior and posterior MIs (p > 0.05). The posterior MI to hemiplate line was greater than that anteriorly (p < 0.05). The apical distance between the posterior MIs was greater than that anteriorly (p < 0.05). The palatal thickness at the anterior MIs was significantly greater than that posteriorly (p > 0.01).

Conclusions

In the coronal plane, the angulation between the anterior MIs in relation to the jackscrew plate was greater than that between the posterior MIs owing to the differential palatal bone thickness.

Accurate gingival segmentation from 3D images with artificial intelligence: an animal pilot study

BACKGROUND

Gingival phenotype plays an important role in dental diagnosis and treatment planning. Traditionally, determining the gingival phenotype is done by manual probing of the gingival soft tissues, an invasive and time-consuming procedure. This study aims to evaluate the feasibility and accuracy of an alternatively novel, non-invasive technology based on the precise 3-dimension (3D) soft tissue reconstruction from intraoral scanning and cone beam computed tomography (CBCT) to predict the gingival biotype.

METHODS

As a proof-of-concept, Yorkshire pig mandibles were scanned, and the CBCT data were fed into a deep-learning model to reconstruct the teeth and surrounding bone structure in 3D. By overlaying the CBCT scan with the intraoral scans, an accurate superposition was created and used for virtual measurements of the soft tissue thickness. Meanwhile, gingival thicknesses were also measured by a periodontal probe and digital caliper on the buccal and lingual sides at 3 mm apical to the gingival margin of the posterior teeth and compared with the virtual assessment at the same location. The data obtained from virtual and clinical measurements were compared by Wilcoxon matched-pairs signed-rank analysis, while their correlation was determined by Pearson's r value. The Mann-Whitney U test was used for intergroup comparisons of the amount of difference.

RESULTS

Among 108 investigated locations, the clinical and virtual measurements are strongly positively correlated (r = 0.9656, P < 0.0001), and only clinically insignificant differences (0.066 ± 0.223 mm) were observed between the two assessments. There is no difference in the agreement between the virtual and clinical measurements on sexually matured samples (0.087 ± 0.240 mm) and pre-pubertal samples (0.033 ± 0.195 mm). Noticeably, there is a greater agreement between the virtual and clinical measurements at the buccal sites (0.019 ± 0.233 mm) than at the lingual sites (0.116 ± 0.215 mm).

CONCLUSION

In summary, the artificial intelligence-based virtual measurement proposed in this work provides an innovative technique potentially for accurately measuring soft tissue thickness using clinical routine 3D imaging systems, which will aid clinicians in generating a more comprehensive diagnosis with less invasive procedures and, in turn, optimize the treatment plans with more predictable outcomes.

Alveolar bone changes after tooth-borne surgically assisted rapid maxillary expansion: A three-dimensional study

INTRODUCTION

Surgically assisted rapid maxillary expansion (SARME) with a dental-anchorage appliance can induce dental and skeletal complications adjacent to the teeth supporting the device. The purpose of this study was to quantify the dentoskeletal changes observed after SARME using a tooth-borne device.

MATERIALS AND METHODS

Cone beam CT images from 39 patients were compared between the preoperative (T1) and the postoperative period (T2). The mean time to complete the second imaging was 13.8 ± 6.9 months after the SARME. Dental and bone parameters were assessed: the vestibular bone height (BH), the bone thickness (BT), the existence of fenestrations, and the root resorption at the level of first upper premolar (P1) and the first upper molar (M1). The maxillary expansion parameters were also collected.

RESULTS

Both vertical and horizontal vestibular bone loss were observed mainly in the first upper molar sectors: The BT decreased from 0.93 ± 0.50 mm to 0.53 ± 0.51 mm (p < 0.0001) and the BH decreased from 1.84 ± 1.05 mm to 0.93 ± 1.02 mm (p < 0.0001) for tooth #16. The bone loss also affected the first upper premolars but in a more limited manner. Significant fenestrations were observed at the apex of the mesio-vestibular root of teeth #16 and #26. We noted significant root resorption affecting the mesio-, disto-vestibular and palatal roots of tooth #16 (mean reductions of 0.32, 0.35, and 0.55 mm, respectively; p < 0.05), and the palatal root of tooth # 26 (loss of 0.58 mm; p = 0.004). The mean bone expansion was 3.76 mm and 1.41 mm at the premolar and molar levels, respectively (p < 0.0001), while a mean 6.24 mm and 4.23 mm inter-cuspid expansion was noted at the P1 and M1 levels (p < 0.0001).

CONCLUSION

Our results document the vestibular bone changes and low root resorption, mostly in the molar sectors, associated with SARME using dental-anchorage devices.