Northcroft revisited

Application of three-dimensional reconstruction technology in dentistry: a narrative review

BACKGROUND

Three-dimensional(3D) reconstruction technology is a method of transforming real goals into mathematical models consistent with computer logic expressions and has been widely used in dentistry, but the lack of review and summary leads to confusion and misinterpretation of information. The purpose of this review is to provide the first comprehensive link and scientific analysis of 3D reconstruction technology and dentistry to bridge the information bias between these two disciplines.

METHODS

The IEEE Xplore and PubMed databases were used for rigorous searches based on specific inclusion and exclusion criteria, supplemented by Google Academic as a complementary tool to retrieve all literature up to February 2023. We conducted a narrative review focusing on the empirical findings of the application of 3D reconstruction technology to dentistry.

RESULTS

We classify the technologies applied to dentistry according to their principles and summarize the different characteristics of each category, as well as the different application scenarios determined by these characteristics of each technique. In addition, we indicate their development prospects and worthy research directions in the field of dentistry, from individual techniques to the overall discipline of 3D reconstruction technology, respectively.

CONCLUSIONS

Researchers and clinicians should make different decisions on the choice of 3D reconstruction technology based on different objectives. The main trend in the future development of 3D reconstruction technology is the joint application of technology.

Distances between facial landmarks can be measured accurately with a new digital 3-dimensional video system

INTRODUCTION

The aim of this study was to investigate a new digital 3-dimensional infrared video system to determine its accuracy, precision, and validity in measuring facial distances.

METHODS

Bench experiments were performed by measuring the vertical and diagonal distances of chessboard squares of known length to determine the system's accuracy and precision. To test the system's validity, 16 healthy volunteers participated in this study. Vertical and horizontal distances of the face were measured electronically at rest, and on posed and aggressive smiles. All measurements were repeated after 8 weeks. Direct measurements of the intercanthal distance were obtained twice with calipers.

RESULTS

A minor systematic error was found in the bench experiments, with the highest absolute error of 0.227 +/- 0.39 mm. The analysis with this video system showed good reproducibility of all measured distances when the mean of 2 frames was used to compare distances. Digital measurements of the intercanthal distances showed high agreement with the clinically obtained values.

CONCLUSIONS

This digital video system can measure geometric distances in a 3-dimensional environment with high precision. Facial distances can be measured with good accuracy and precision, allowing applications in research and clinical practice.

Three-dimensional surface acquisition systems for the study of facial morphology and their application to maxillofacial surgery

BACKGROUND

There has been a growing interest in three-dimensional (3D) surface imaging devices over the last few years.

METHODS

This comprehensive review discusses the various emerging technologies in this field of 3D imaging and applies the use of technology to oral and maxillofacial imaging.

RESULTS

The paper shows that there is increased awareness and application of technology to the field.

CONCLUSION

3D surface acquisition technology is improving at a rapid pace and has a place in oral and maxillofacial surgery.

That great palace of truth

This December sees the 100th anniversary of the formation of the British Society for the Study of Orthodontics, founded by George Northcroft and now subsumed into the British Orthodontic Society. This article takes a brief look at Northcroft and his legacy, part of which will be on display in the BDA Museum between May and July this year to mark the centenary of the society Northcroft founded.

A Three-Dimensional Evaluation of Postoperative Swelling following Orthognathic Surgery at 6 Months

BACKGROUND

Advances in three-dimensional technology have enabled applications for the clinical setting to be created and used in routine diagnosis, treatment planning, and patient education. The objectives of this prospective clinical trial were to determine the volume changes associated with facial swelling following orthognathic surgery.

METHODS

Twelve subjects requiring orthognathic surgery were recruited for the study. Laser scanned images of the subjects were obtained under a reproducible, controlled environment with two laser-scanning devices assembled as a stereo pair. Three-dimensional laser scans were recorded over six time periods, as follows: T1, presurgical scan; T2, 1 day postoperatively; T3, 1 week postoperatively; T4, 1 month postoperatively; T5, 3 months postoperatively; and T6, 6 months postoperatively.

RESULTS

The results showed a clinical difference in the mean shell deviations between bimaxillary and single-jaw orthognathic surgery. Furthermore, the results suggest that the mean volume of swelling was reduced by approximately 60 percent within the first month after surgery. Finally, the amounts of swelling following surgery were greater in bimaxillary cases. The recovery in the swelling was also faster in this group of patients.

CONCLUSIONS

Three-dimensional imaging has opened up new avenues of patient care and treatment evaluation. The results have shown that the laser scanning device and the method described are a reliable and accurate measure of facial swelling following surgery.

The use of three-dimensional imaging in orthodontics

The article illustrates the value of three-dimensional imaging of the face and jaws in the diagnosis and treatment of patients. The applications of programs that have been written for the analysis of facial form are also described, including registration and prediction. The use of the Procrustes analysis is demonstrated in groups of children and adults to differentiate between male and female facial morphology. The use of scanning in forensic science is also described. The application of surface shape analysis to groups of monozygotic and dizygotic twins and to family studies to detect those areas that are genetically determined from those areas, which are not, is illustrated.

A new method for the 3D measurement of postoperative swelling following orthognathic surgery

OBJECTIVE

To describe a new method for measuring facial swelling following orthognathic surgery using a 3D laser-scanning device.

DESIGN

Prospective clinical trial. Setting and Sample Population -- University Dental Hospital, Wales College of Medicine, Biology Life and Health Sciences. Three subjects requiring bi-maxillary orthognathic surgery were recruited for the study.

EXPERIMENTAL VARIABLES

Laser-scanned images of the subjects were obtained under a reproducible and controlled environment with two Minolta Vivid 900 (Osaka, Japan) optical laser-scanning devices assembled as a stereo-pair. A set of left and right scanned images was taken for each subject and each scan took an average of 2.5 s. 3D laser scans were recorded over six time periods (T1 -- pre-surgical scan, postoperatively: T2 -- 1 day, T3 -- 1 week, T4 -- 1 month, T5 -- 3 months and T6 -- 6 months).

OUTCOME MEASURE

Facial scans from different time periods were overlaid onto the baseline (T6) facial scan to determine the reduction and changes in swelling following orthognathic surgery.

RESULTS

The results showed that swelling could be accurately quantified following surgery. Furthermore, there was a significant reduction in the amount of swelling 1 month postoperatively. Furthermore, the facial morphology returned to approximately 90% of the baseline facial scan at 3 months.

CONCLUSION

The 3D laser-scanning device and the method described was a reliable and accurate measure of facial swelling following surgery.