A novel CAD/CAM composite occlusal splint for intraoperative verification in single-splint two-jaw orthognathic surgery

Does curve of Spee affect the precision of 3D-printed curvature-adaptive splints?

OBJECTIVES

This study aimed to propose a standardized protocol for the fabrication of three-dimensionally (3D)-printed curvature-adaptive splints (CASs) and assess the precision of CASs on dentitions with different depths of the curve of Spee (COS).

METHODS

76 lower dental resin models, each exhibiting one of the four types of COS (0-, 2-, 4-, and 6-mm deep), were selected and digitally scanned. CASs were designed, 3D printed, and grouped into C0, C2, C4, and C6, corresponding to the four types of COS depths. To assess precision, the CASs occluded with the resin model were scanned as a whole and compared with the originally designed ones.

RESULTS

In terms of translational deviations observed in the CASs, the mean value of absolute sagittal deviation (0.136 mm) was significantly higher than those of vertical (0.091 mm) and transversal deviations (0.045 mm) (P < 0.01). Regarding rotational deviations of the CASs, the mean deviation in pitch (0.323°) was significantly higher than those in yaw (0.083°) and roll (0.110°) (P < 0.01). However, when comparing the accuracy of CASs across C0, C2, C4, and C6 groups, no statistically significant difference was found. Additionally, the translational deviations, rotational deviations, and RMSE of all groups were significantly lower than the clinically acceptable limits of 0.5 mm, 1°, and 0.25 mm, respectively (P < 0.01).

CONCLUSIONS

The depth of the COS has no significant impact on the precision of CASs, as evidenced by the absence of statistically significant differences in translational, rotational deviations, and RMSE among all groups (C0, C2, C4, and C6). Moreover, despite relatively high deviations in the sagittal dimension and pitch, all dimensional deviations and RMSE remained statistically significantly lower than the corresponding clinically acceptable limits (CALs) in all groups.

CLINICAL SIGNIFICANCE

This standardized protocol incorporating "curvature-adaptation" represents an optimized approach to fabricating diverse 3D-printed splints tailored to dentitions with different anatomical features in contemporary digital dentistry.

Lefort 1 Osteotomy Study of Maxillary Bone in Caprine Skull Model: Comparison of Different Osteotomy Techniques (Piezo Versus Lindemann Bur Versus Manual Chisel)

OBJECTIVE

In this study, we aimed to compare the efficiency of different osteotomy techniques for Lefort 1 osteotomy in an experimental caprine skull model.

METHODS

Twelve caprine skulls were used for the study. Skulls were divided into 3 groups: (1) manual chisel group, (2) Lindemann bur group, and (3) piezo osteotomy group. Bilateral osteotomies were performed on each skull. Results were evaluated with three-dimensional computerized tomography scans and macroscopic observations of the mucosal tears and soft tissue.

RESULTS

The mean length of the bone gap in the manual, Lindemann, and piezo groups was 4.8 (±0.7), 3.38 (±1.49), and 1.39 (±0.3) mm, respectively ( P < 0.05). The mean number of comminuted fractures in the manual, Lindemann, and piezo groups was 5.5 (±1.4), 1.6 (±0.3), and 0.6 (±0.5), respectively ( P < 0.05). Mucosal tearing and soft tissue damage based on subjective inspection observations were negligible in the piezo technique. Soft tissue and mucosal damage were observed significantly more in the manual chisel osteotomy method compared with the other 2 techniques.

CONCLUSION

We anticipate that piezo, which has started to be used in new application areas besides rhinoplasty, will continue to be used more widely, especially in reconstructive orthognathic surgery, due to the minimal damage it causes to tissues. With the long-term results, much healthier interpretations can be made.

Effect of offset on the precision of 3D-printed orthognathic surgical splints

OBJECTIVE

This study evaluated the effect of offset on the precision of three-dimensional (3D)-printed splints, proposing to optimize the splint design to compensate for systematic errors.

MATERIALS AND METHODS

14 resin model sets were scanned and offset as a whole by given distances (0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, and 0.40 mm). Intermediate splints (ISs) and final splints (FSs) were generated from the non-offset and offset models and grouped correspondingly, named as splint type-offset value, IS-0.05, for instance. Dentitions occluded with the splint were scanned. Translational and rotational deviations of the lower dentition relative to the upper dentition were 3D measured.

RESULTS

Deviations of ISs and FSs were more evident in the vertical and pitch dimensions, and were mostly acceptable in other dimensions. ISs with offset ≥ 0.05 mm showed vertical deviations significantly below 1 mm (P < 0.05) while ISs with 0.10- to 0.30-mm offsets had pitch rotations significantly lower than 1° (P < 0.05). The Pitch of IS-0.35 was significantly larger than ISs with 0.15- to 0.30-mm offsets (P < 0.05). Meanwhile, FSs fit better as the offset increased and FSs with offsets ≥ 0.15 mm all had deviations significantly lower than 1 mm (for translation) or 1° (for rotation) (P < 0.05).

CONCLUSIONS

Offset affects the precision of 3D-printed splints. Moderate offset values of 0.10 to 0.30 mm are recommendable for ISs. Offset values ≥ 0.15 mm are recommended for FSs in cases with stable final occlusion.

CLINICAL RELEVANCE

This study found the optimal offset ranges for 3D-printed ISs and FSs via a standardized protocol.

Applications of three-dimensional imaging techniques in craniomaxillofacial surgery: A literature review

Three-dimensional (3D) imaging technologies are increasingly used in craniomaxillofacial (CMF) surgery, especially to enable clinicians to get an effective approach and obtain better treatment results during different preoperative and postoperative phases, namely during image acquisition and diagnosis, virtual surgical planning (VSP), actual surgery, and treatment outcome assessment. The article presents an overview of 3D imaging technologies used in the aforementioned phases of the most common CMF surgery. We searched for relevant studies on 3D imaging applications in CMF surgery published over the past 10 years in the PubMed, ProQuest (Medline), Web of Science, Science Direct, Clinical Key, and Embase databases. A total of 2094 articles were found, of which 712 were relevant. An additional 26 manually searched articles were included in the analysis. The findings of the review demonstrated that 3D imaging technology is becoming increasingly popular in clinical practice and an essential tool for plastic surgeons. This review provides information that will help researchers and clinicians consider the use of 3D imaging techniques in CMF surgery to improve the quality of surgical procedures and achieve satisfactory treatment outcomes.

Artificial Intelligence Splint in Orthognathic Surgery for Skeletal Class III Malocclusion: Design and Application

BACKGROUND

Digital splints are indispensable in orthognathic surgery. However, the present design process of splints is time-consuming and has low reproducibility. To solve these problems, an algorithm for artificial intelligent splints has been developed in this study, making the automatic design of splints accessible.

METHODS

Firstly, the algorithm and program of the artificial intelligence splint were created. Then a total of 54 patients with skeletal class III malocclusion were included in this study from 2018 to 2020. Pre and postoperative radiographic examinations were performed. The cephalometric measurements were recorded and the difference between virtual simulation and postoperative images was measured. The time cost and differences between artificial intelligent splints and digital splints were analyzed through both model surgery and radiographic images.

RESULTS

The results showed that the efficiency of designing splints is significantly improved. And the mean difference between artificial intelligent splints and digital splints was <0.15 mm in model surgery. Meanwhile, there was no significant difference between the artificial intelligent splints and digital splints in radiological image analysis.

CONCLUSIONS

In conclusion, compared with digital splints, artificial intelligent splints could save time for preoperative design while ensuring accuracy. The authors believed that it is conducive to the presurgical design of orthognathic surgery.

Surgical Precision Analysis of Orthognathic Surgery Combined With Invisible Orthodontic

BACKGROUND

This study aimed to explore the changes in hard tissue after applying invisible orthodontic-orthognathic treatment and the digital design, and to explore the accuracy of the treatment effect of maxillofacial tissue after invisible orthodontic treatment and orthognathic treatment.

METHODS

From September 2020 to January 2022, 25 patients with class III skeletal malocclusion and 7 patients with class II skeletal malocclusion, were treated with invisible orthodontic treatment and orthognathic combined treatment. Orthodontic treatment with preoperative invisible orthodontic treatment followed by orthodontic surgery. All patients had cephalometric lateral films after surgery to analyze orthognathic surgery's goals and surgical effects of orthognathic surgery and the digital design. Measure the angle of the sella-nasion-A point angle, angle of sella-nasion-B point, ANB angle, maxillary convex angle, mandibular plane (MP) angle, 1-SN angle, 1-MP angle, etc, and compare surgery outcome with digital design.

RESULT

All patients were satisfied with the effect and no complications occurred. Angle of sella-nasion-A point, angle of sella-nasion-B point, ANB angle, maxillary convex angle, MP angle, 1-SN angle, and 1-MP angle had no significant difference between the postoperative effect and the purpose of digital design ( P >0.05), there was no apparent deviation between the upper and lower jaw and the chin ( P >0.05).

CONCLUSION

The combined invisible orthodontic treatment and orthognathic treatment are accurate and effective, and are worthy of promotion. It supplements traditional orthognathic therapy and is suitable for corresponding patients.

Clinical Application of CAD/CAM-Guided Modified Dautrey's Procedure in Recurrent Temporomandibular Joint Luxation

This study aimed to introduce the clinical application of the CAD/CAM-guided modified Dautrey's procedure in recurrent anterior temporomandibular joint luxation and evaluate its clinical effects. Four selected patients were treated by the CAD/CAM-guided modified Dautrey's procedure and were followed-up to access their curative effect. Joint pain and sound, recurrence rate, mandibular function, maximum mouth opening (MMO), symptoms of facial nerve injury, and changes in zygomatic facial appearance were observed in postoperative follow-up. The followed-up period ranged from 3 months to 1 year with an average time of 7.5 months. There was no recurrence in all 4 patients, and no symptoms of facial nerve injury and zygomaticofacial appearance changes were found. All patients showed improvement in MMO, with a mean preoperative and postoperative MMO of 4.74 and 3.74 cm, respectively. All of them showed relief of joint pain or sound 3 months or more after the operation and could exercise mandibular normally. This results showed that the CAD/CAM-guided modified Dautrey's procedure was effective in the treatment of recurrent temporomandibular joint luxation and could be used as a good alternative treatment for it.

[Research progress of digital occlusion setup in orthognathic surgery]

Objective

To review the research progress of digital occlusion setup in orthognathic surgery.

Methods

The literature related to digital occlusion setup in orthognathic surgery in recent years was consulted, and the imaging basis, methods, clinical applications as well as existing problems were reviewed.

Results

Digital occlusion setup in orthognathic surgery includes manual, semi-automatics, and fully automatic methods. The manual method mainly relies on visual cues for operation, which is difficult to ensure the best occlusion set up, though relatively flexible. The semi-automatic method utilizes the computer software for partial occlusion set up and adjustment, but the occlusion result is still largely depended by manual operation. The fully automatic method completely depends on the operation of computer software, and targeted algorithms for different occlusion reconstruction situations are needed.

Conclusion

The preliminary research results have confirmed the accuracy and reliability of digital occlusion setup in orthognathic surgery, but there are still some limitations. Further research is needed in terms of postoperative outcomes, doctor and patient acceptance, planning time and cost-effectiveness.

This is not a pipe - But how harmful is electronic cigarette smoke

This issue of the Biomedical Journal tells us about the risks of electronic cigarette smoking, variations of SARS-CoV-2 and ACE2, and how COVID-19 affects the gastrointestinal system. Moreover, we learn that cancer immunotherapy seems to work well in elderly patients, how thyroid hormones regulate noncoding RNAs in a liver tumour context, and that G6PD is a double-edged sword of redox signalling. We also discover that Perilla leaf extract could inhibit SARS-CoV-2, that artificial neural networks can diagnose COVID-19 patients and predict vaccine epitopes on the Epstein-Barr Virus, and that men and women have differential inflammatory responses to physical effort. Finally, the surgical strategies for drug-resistant epilepsy, computer-supervised double-jaw surgery, dental pulp stem cell motility, and the restitution of the brain blood supply after atherosclerotic stroke are discussed.