Accuracy of three-dimensional optical devices for facial soft-tissue measurement in clinical practice of stomatology: A PRISMA systematic review

Positional accuracy of intraoral scan alignment to a facial scan using structured light scanning and trial denture base with occlusal rim markers in patients with complete maxillary edentulism

STATEMENT OF PROBLEM

Creating precise 3D virtual head models for patients with complete maxillary edentulism remains challenging owing to the lack of natural landmarks and limitations of current image-matching technologies.

PURPOSE

The purpose of this study was to evaluate the positional accuracy of intraoral scan alignment to structured light-based facial scans using varying sizes and positions of occlusal rim markers under maxillary edentulous conditions.

MATERIAL AND METHODS

Radiopaque artificial markers of 3 sizes (2, 4, and 6 mm) were made and attached to the maxillary occlusal rim of a completely edentulous patient at different positions (midline-canine [MC], midline [M], canine [C]). Facial scans were obtained of the patient by using a structured light facial scanner under 9 experimental conditions (size-location: 2MC, 2M, 2C, 4 MC, 4M, 4C, 6MC, 6M, and 6C; 5 scans under each condition). Intraoral scans were aligned to the facial scans using stepwise images matching the occlusal rim scan casts. The alignment accuracy was evaluated by comparing the intraoral scan with a reference position established using cone beam computed tomography data. Measured variables included anterior and posterior linear deviations and angular deviation of the arch plane. Statistical analysis was conducted using the Kruskal-Wallis test and Mann-Whitney U test with Bonferroni correction (α=.05).

RESULTS

The 4-mm and 6-mm marker groups exhibited significantly lower deviation in image registration than the groups without markers and those with 2-mm markers (P<.001). Regarding the marker position, the midline-canine group exhibited the lowest deviation value, followed by the midline and canine groups. Markers positioned in the midline exhibited less deformation compared with those in the canine region.

CONCLUSIONS

Occlusal rim markers can be used to align intraoral and facial scans in patients with complete maxillary edentulism when structured light face scanning is included. Markers with a clearly recognizable size in facial scans are less prone to deformation in the facial midline area.

Changes in Facial Soft Tissue Asymmetry in Class II Patients One Year After Orthognathic Surgery

Objectives: The objective of this study was to examine changes in facial soft tissue asymmetry over time in patients after Class II orthognathic surgery using three-dimensional (3D) stereophotogrammetry. Methods: The study consists of 54 patients with a skeletal Class II malocclusion (32 female, 22 male; mean age, 33.2 years). Three-dimensional photographic data were collected using the 3dMD Trio stereophotogrammetry system. The evaluation of 21 anthropometric landmark positions was conducted before surgery (T0), 6 months (T1), and 12 months (T2) after surgery. Facial asymmetry was classified as mild (0-2 mm), moderate (3-5 mm), or severe (>5 mm). Results: There was a small difference in the mean distance when analyzing the asymmetry of the whole face. The 3D measurements showed statistically significant differences (p < 0.05) between T0 versus T1 and T2 time-point values. Prior to surgery, males exhibited a higher degree of soft tissue asymmetry compared to females. The chin volume asymmetry score was higher in the females of the cohort and patients undergoing bimaxillary surgery (median 1.11) than in the males of the cohort and patients undergoing single-jaw surgery (median 1.08); however, these differences were not statistically different. Conclusions: The findings indicate that soft tissue asymmetry may become altered within a 6-month period following surgery.

Two-dimensional facial photography for assessment of craniofacial morphology in sleep breathing disorders: a systematic review

PURPOSE

Craniofacial morphology is integral to Sleep Breathing Disorders (SBD), particularly Obstructive Sleep Apnea (OSA), informing treatment strategies. This review assesses the utility of two-dimensional (2D) photogrammetry in evaluating these metrics among OSA patients.

METHODS

Following PRISMA guidelines, a systematic review was conducted. PubMed, Embase, and Lilacs databases were systematically searched for studies utilizing 2D photography in SBD. Findings were narratively synthesized.

RESULTS

Thirteen studies involving 2,328 patients were included. Significant correlations were found between craniofacial measurements-specifically neck parameters and facial width-and OSA severity, even after BMI adjustment. Ethnic disparities in craniofacial morphology were observed, with photogrammetry effective in predicting OSA in Caucasians and Asians, though data for other ethnicities were limited. Pediatric studies suggest the potential of craniofacial measurements as predictors of childhood OSA, with certain caveats.

CONCLUSION

2D photogrammetry emerges as a practical and non-invasive tool correlating with OSA severity across diverse populations. However, further validation in various ethnic cohorts is essential to enhance the generalizability of these findings.

3D Analysis of the Cranial and Facial Shape in Craniosynostosis Patients: A Systematic Review

With increasing interest in 3D photogrammetry, diverse methods have been developed for craniofacial shape analysis in craniosynostosis patients. This review provides an overview of these methods and offers recommendations for future studies. A systematic literature search was used to identify publications on 3D photogrammetry analyses in craniosynostosis patients until August 2023. Inclusion criteria were original research reporting on 3D photogrammetry analyses in patients with craniosynostosis and written in English. Sixty-three publications that had reproducible methods for measuring cranial, forehead, or facial shape were included in the systematic review. Cranial shape changes were commonly assessed using heat maps and curvature analyses. Publications assessing the forehead utilized volumetric measurements, angles, ratios, and mirroring techniques. Mirroring techniques were frequently used to determine facial asymmetry. Although 3D photogrammetry shows promise, methods vary widely between standardized and less conventional measurements. A standardized protocol for the selection and documentation of landmarks, planes, and measurements across the cranium, forehead, and face is essential for consistent clinical and research applications.

Predicting obstructive sleep apnea hypopnea syndrome using three-dimensional optical devices: A systematic review

Purpose

As a global health concern, the diagnosis of obstructive sleep apnea hypopnea syndrome (OSAHS), characterized by partial reductions and complete pauses in ventilation, has garnered significant scientific and public attention. With the advancement of digital technology, the utilization of three-dimensional (3D) optical devices demonstrates unparalleled potential in diagnosing OSAHS. This study aimed to review the current literature to assess the accuracy of 3D optical devices in identifying the prevalence and severity of OSAHS.

Methods

A systematic literature search was conducted in the Web of Science, Scopus, PubMed/MEDLINE, and Cochrane Library databases for English studies published up to April 2024. Peer-reviewed researches assessing the diagnostic utility of 3D optical devices for OSAHS were included. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) guideline was employed to appraise the risk of bias.

Results

The search yielded 3216 results, with 10 articles meeting the inclusion criteria for this study. Selected studies utilized structured light scanners, stereophotogrammetry, and red, green, blue-depth (RGB-D) cameras. Stereophotogrammetry-based 3D optical devices exhibited promising potential in OSAHS prediction.

Conclusions

The utilization of 3D optical devices holds considerable promise for OSAHS diagnosis, offering potential improvements in accuracy, cost reduction, and time efficiency. However, further clinical data are essential to assist clinicians in the early detection of OSAHS using 3D optical devices.