Mixed reality for extraction of maxillary mesiodens

Association between 3D characteristics of single unilaterally impacted mesiodens and root development of adjacent maxillary central incisors: a retrospective study with cone-beam computed tomography

OBJECTIVES

This study aimed to evaluate the detrimental effects of single unilaterally impacted mesiodens on the root development of adjacent maxillary central incisors and to explore the key influencing factors.

METHODS

A total of 552 patients aged 5-12 years with single unilaterally impacted mesiodens were included in the study. The maxillary central incisor with greater overlap with the mesiodens in the coronal view was identified as the affected tooth, while the contralateral central incisor served as the control one. Cone-beam computed tomography (CBCT) data for these patients were retrospectively analyzed to compare the root lengths and root formation stages of the maxillary central incisors on both sides. Multivariate logistic regression and generalized linear models were used to investigate the critical 3-dimensional (3D) characteristics that influence the root development of adjacent maxillary central incisors.

RESULTS

Maxillary central incisors on the affected side exhibited significantly shorter root lengths and less-advanced root formation stages compared to those on the control side. Impacted mesiodens with tuberculate or germ morphology, normal or undefined orientation, and a position superior to dental cervix of contralateral central incisor were associated with higher risk of impairing root development of adjacent central incisors.

CONCLUSIONS

Impacted mesiodens can impair the root development of adjacent central incisors. Early removal of high-risk mesiodens is essential for safeguarding the future development of adjacent maxillary central incisors.

Enhancing the accuracy of genioplasty using mixed reality and computer-aided design/manufacturing: a randomized controlled trial

Background

Genioplasty is performed as part of orthognathic surgery to correct jaw deformities. This procedure presents challenges in terms of osteosynthesis accuracy. This study aimed to evaluate the precision of preoperative planning in genioplasty using computer-aided design/computer-aided manufacturing (CAD/CAM) with three-dimensional (3D) printable biomaterials and mixed reality (MR) technology with a head-mounted display (Microsoft® HoloLens 2) and a registration marker.

Methods

Twenty-six patients underwent genioplasty using either only CAD/CAM devices (control group, n=10) or CAD/CAM with additional MR technology (experimental group, n=16). CAD/CAM devices were created based on virtual surgical planning (VSP), and MR holograms created based on VSP data were projected onto the surgical area using Microsoft HoloLens 2. After surgery, the planned model was compared with the postoperative computed tomography (CT) image, measuring the 3D surface and the differences in position and rotation using the root mean square deviation (RMSD) and Bland-Altman's method. Both analyses are blinded.

Results

The average 3D surface analysis errors within 2 mm ranged between 62.20-100.00% (control group) and 99.30-100.00% (experimental group), with mean errors of 92.12% and 99.81%, respectively. Errors within 1 mm ranged between 28.50-98.90% (control group) and 55.10-99.6% (experimental group) with mean errors of 67.36% and 85.60%, respectively. The largest RMSDs were 1.20 mm in the anteroposterior direction and 6.78° in pitch orientation for the experimental group and 1.78 mm in the anteroposterior direction and 6.04° in pitch orientation for the control group. A statistically significant difference between the two groups was observed for errors measured within 1 mm (P=0.047) and for yaw (P=0.003). No postoperative complications were observed in either group.

Conclusions

Using CAD/CAM with additional MR technology in genioplasty improved the repositioning accuracy of the chin bone fragment and plate placement, with statistically significant improvements in specific spatial directions. This combination of CAD/CAM and MR technology allows for intraoperative spatial verification of fragment movement according to preoperative VSP, which significantly contributes surgical precision.

Surgical Approach to Bilateral Impacted and Inverted Mesiodentes in a Nonsyndromic Pediatric Patient: A Case Report and Brief Literature Review

Supernumerary teeth (ST) are a form of abnormal dental development and may not always present with symptoms. This case report discusses an eight-year-old child who presented with spacing in the maxillary anterior region. Radiographic examination revealed bilateral impacted and inverted mesiodentes, which were successfully managed through surgical extraction and orthodontic treatment. The postoperative course was uneventful, resulting in satisfactory outcomes for both the patient and his parents. We emphasize the importance of periodic check-ups during the early stages of tooth exfoliation, including proactive clinical and radiographic evaluations for the early diagnosis and management of multiple ST. Along with a review of the literature, this report suggests that a timely surgical approach should be indicated to effectively address the patient's condition, ensuring optimal outcomes with minimal intervention.

Clinical application of mixed reality holographic imaging technology in scaling and root planing of severe periodontitis: a proof of concept

OBJECTIVES

To demonstrate the potential application of mixed reality (MR) holographic imaging technology in subgingival scaling and root planing (SRP) for patient with advanced periodontitis.

METHODS

This case series comprised the analysis of 1566 sites from 261 teeth of 10 patients with advanced periodontitis. Digital CBCT scans and intraoral scans of the patients were digitally acquired preoperatively and aligned to create a three-dimensional periodontal visualization model. Through rendering, interactive holographic images were displayed using MR. The surgeon first used MR images to communicate with the patients, and then facilitated SRP under their guidance. Probing pocket depth (PPD), clinical attachment loss (CAL), Plaque index (PI), and bleeding on probing (BOP) parameters were recorded at baseline and at 8-week postoperatively. Patient-reported outcome indicator questionnaires on self-efficacy were also collected.

RESULTS

PPD, CAL, PI, and BOP significantly decreased at 8-week following MR hologram-assisted SRP (p<0.001). For sites with PPD≥4 mm, PPD and CAL declined by 2.33±1.23 mm and 0.69±1.07 mm, respectively. PI significantly decreased from 1.94±0.61 to 0.82±0.58 (p < 0.001) and BOP sites decreased significantly from 84.11% to 40.25%. After receiving MR holograms for condition communication, most patients had a better perception of the effectiveness of SRP treatment and the benefits it brings. 80% of the subjects expressed their willingness to undergo MR-assisted periodontal treatment in the future.

CONCLUSION

These results provide preliminary support for MR hologram-assisted digital SRP. With this technology, images of the gingiva and alveolar bone can be displayed in real time, accurately and three-dimensionally. This improves SRP effectiveness, diminishes complications, and enhances patients' confidence in the treatment.

CLINICAL SIGNIFICANCE

MR holographic imaging-based digital SRP is a clinically feasible and promising adjunctive periodontal treatment option. It may contribute to improved non-surgical treatment efficacy in patients with severe periodontitis.

Double Mesiodens in the Mixed Dentition of Non-syndromic North-Indian Patients: A Case Series

The presence of double mesiodens or mesiodentes, i.e., two supernumerary teeth in the maxillary midline, presents unique challenges in mixed dentition. Common clinical manifestations include delayed eruption, midline diastema, and occlusal disturbances, leading to complications such as root resorption, pathological migration of tooth, crowding, cyst formation, and malocclusion. Mesiodens can be associated with several syndromes, like cleidocranial dysplasia, familial adenomatous polyposis, trichorhinophalangeal syndrome, type I, Rubinstein-Taybi syndrome, and Nance-Horan syndrome, among others. It can also be secondary to trauma, hyperactivity of the dental lamina, and a combination of genetic and environmental factors, but its etiology continues to be idiopathic. Double mesiodens are relatively rare, so this clinical observation aimed to highlight five such cases of double mesiodens in mixed dentition in non-syndromic children and adolescents. Additionally, a literature search reporting cases of double mesiodens in the mixed dentition was done, and the results were tabulated. Clinicians should be able to identify indications of supernumerary teeth, specifically deviations in the eruption pattern. Appropriate investigations and timely intervention are essential to reducing complications that may arise in the developing dentition.