Interdisciplinary guided dentistry, digital quality control, and the "copy-paste" concepts

A comparative study of the use of digital technology in the anterior smile experience

OBJECTIVES

this study aims to compare the clinical outcomes of traditional and digital crown extension guides in the aesthetic restoration of anterior teeth. Additionally, the study will analyze the differences in the results of various digital crown extension guides in anterior aesthetic restorations.

METHODS

Sixty-two patients who required aesthetic restoration of their anterior teeth were selected for this study. The patients had a total of 230 anterior teeth and were randomly divided into three groups: a control group of 22 cases who received diagnostic wax-up with pressure film, an experimental group 1 of 20 cases who received 3D printed digital models with pressure film, and an experimental group 2 of 20 patients who received digital dual-positioning guides. The control group had a total of 84 anterior teeth, experimental group 1 had 72 anterior teeth, and experimental group 2 had 74 anterior teeth. The study compared three methods for fabricating crown extension guides: the control group used the diagnostic wax-up plus compression film method, while experimental group 1 used compression film on 3D printed models and experimental group 2 used 3D printed digital dual-positioning crown extension guides. After the crown lengthening surgery, the control group patients wore DMG resin temporary crown material for gingival contouring, while the experimental group patients wore 3D printed resin temporary crowns for the same purpose. The patients were followed up in the outpatient clinic after wearing temporary crowns for 1 month, 3 months, and 6 months, respectively. The clinical results were evaluated in terms of marginal fit, red aesthetic index, and white aesthetic index.

RESULTS

Based on the statistical analysis, the experimental group required significantly fewer follow-up visits and less time for guide design and fabrication compared to the control group. Additionally, the surgical time for the experimental group was significantly shorter than that of the control group. During the postoperative period between the 1st and 3rd month, the PES index scores for the marginal gingival level, proximal, and distal mesiodistal gingival papillae of the experimental group showed a trend of superiority over those of the control group. By the 6th month, the marginal gingival level exhibited a significant difference between the experimental and control groups. The experimental group demonstrated superior results to the control group in terms of shape, contour, and volume of the teeth, color, surface texture, and transparency of the restorations, and features during the 1st and 3rd postoperative months. In the 6th month, the comparative results indicated that the experimental group continued to exhibit superior outcomes to the control group in terms of the shape, color, surface texture, and transparency of the restorations, as well as the characteristics of the teeth. Additionally, the experimental group demonstrated significantly fewer gingival alterations than the control group at 1 month, 3 months, and 6 months post-procedure, with this difference being statistically significant. Furthermore, the combination of 3D printing technology and restorative techniques was utilized, resulting in consistent patient satisfaction.

CONCLUSION

Digitalisation plays an important role in anterior aesthetic restorations. The use of digital technology to manage the entire process of anterior cosmetic restorations can improve restorative results, reduce the number of follow-up appointments, shorten consultation time, and achieve better patient satisfaction.

Establishment of a 3D esthetic analysis workflow on 3D virtual patient and preliminary evaluation

BACKGROUND

In esthetic dentistry, a thorough esthetic analysis holds significant role in both diagnosing diseases and designing treatment plans. This study established a 3D esthetic analysis workflow based on 3D facial and dental models, and aimed to provide an imperative foundation for the artificial intelligent 3D analysis in future esthetic dentistry.

METHODS

The established 3D esthetic analysis workflow includes the following steps: 1) key point detection, 2) coordinate system redetermination and 3) esthetic parameter calculation. The accuracy and reproducibility of this established workflow were evaluated by a self-controlled experiment (n = 15) in which 2D esthetic analysis and direct measurement were taken as control. Measurement differences between 3D and 2D analysis were evaluated with paired t-tests.

RESULTS

3D esthetic analysis demonstrated high consistency and reliability (0.973 < ICC < 1.000). Compared with 2D measurements, the results from 3D esthetic measurements were closer to direct measurements regarding tooth-related esthetic parameters (P<0.05).

CONCLUSIONS

The 3D esthetic analysis workflow established for 3D virtual patients demonstrated a high level of consistency and reliability, better than 2D measurements in the precision of tooth-related parameter analysis. These findings indicate a highly promising outlook for achieving an objective, precise, and efficient esthetic analysis in the future, which is expected to result in a more streamlined and user-friendly digital design process. This study was registered with the Ethics Committee of Peking University School of Stomatology in September 2021 with the registration number PKUSSIRB-202168136.

Computer aided design/computer aided manufacturing (CAD/CAM) technology in the undergraduate dental programs in the MENA region

INTRODUCTION

The aim of this study was to understand the trends of teaching Computer Aided Design/Computer Aided Manufacturing (CAD/CAM) in the undergraduate dental curriculum in the MENA region by conducting an online survey among the undergraduate dental colleges in this region.

MATERIALS AND METHODS

An online survey was conducted using Google Forms consisting of 20 questions that could be answered by "yes" or "no" responses, multiple-choice answers or in a descriptive, "open" format. A total of 55 participants from the MENA region representing their dental college were requested to participate in this study.

RESULTS

The response rate of the survey was 85.5% following the twofold follow-up reminders method. Although the vast majority of professors demonstrated vital knowledge in the practical use of CAD/CAM, the majority of them did not provide theoretical and practical training on CAD/CAM in their institutions. Among the schools with established levels of teaching CAD/CAM, nearly 50% of them provide both pre-clinical and clinical training on CAD/CAM. Despite the availability of extra-curricular training courses on CAD/CAM outside the university setting, there is a lack of advocating for students to enrol in those courses by the institutions. More than 80% of the participants agreed that CAD/CAM has a strong future in chair-side dental clinics and CAD/CAM needs to be incorporated within undergraduate studies.

CONCLUSION

Based on the results of the current study, it is understandable that an intervention is required by the dental education providers to cope with the growing demand for CAD/CAM technology for the current and future dental practitioners of the MENA region.

In Vitro Evaluation of Accuracy and Reliability of Tooth Shade Selection Using Different Digital Instruments

Introduction Managing tooth shade is a significant challenge in aesthetic dentistry, especially for anterior restorations. Accurate shade assessment, combined with tailored treatment strategies and effective communication, is crucial. To improve the precision and reliability of aesthetic dental treatments, new shade-matching technologies have emerged. Current clinical methods for determining tooth shade utilize both visual assessments and instrumental techniques. The current study aimed to assess and compare the reliability and accuracy of four digital methods of tooth shade matching. Materials and methods This study utilized a 3D-printed resin upper arch model with tooth preparation done on tooth 11. An intraoral scanner was employed to scan and design the tooth, followed by the fabrication of 30 zirconia crowns using computer-aided design and computer-assisted manufacturing (CAD/CAM). The assessment of shade matching involved four digital photometric methodologies (group 1: twin flash + digital single-lens reflex (DSLR) camera (DT), group 2: ring flash + DSLR camera (DR), group 3: smartphone camera (SMART), group 4: intraoral scanner (IOS)) with Commission Internationale de l'Eclairage (CIEL*a*b*) values determined through Adobe Photoshop transformation. Accuracy (ΔE) was calculated and a specific shade using Vitablocs Mark II 3D-Master served as the standard. CIEL*a*b* data (where L = lightness, a and b = chromaticity coordinates) from four cohorts were analyzed in SPSS 26.0 for reliability, with intraclass correlation. The Kruskal-Wallis test and Spearman's correlation assessed reliability, while a one-sample t-test assessed accuracy, comparing values to clinical thresholds (p<0.05). Results The intraclass correlation revealed noteworthy variations in the L*, a*, and b* values, spanning from 0.730 to 0.994, 0.885 to 0.992, and 0.881 to 0.997, respectively. Intraoral scanners demonstrated high accuracy (ΔE = 5.8), while the SMART method showed the lowest precision (ΔE = 12.09). Twin flash with DSLR (TF+DSLR) and ring flash with DSLR (RF+DSLR) displayed comparable precision, with ΔE values of 10.90 and 10.97 respectively. Conclusion The smartphone exhibited the least precision, displaying notable discrepancies in all CIEL*a*b* metrics when compared to the manufacturer-specified shades. Conversely, the intraoral scanner demonstrated higher accuracy and reliability compared to the other groups, with no discernible variation in any of the CIEL*a*b* values from the manufacturer's standard.

The crown lengthening double guide and the digital Perio analysis

OBJECTIVE

This article describes a surgical crown lengthening double guide, which was digitally obtained to improve diagnosis, treatment outcome, and follow-up.

CLINICAL CONSIDERATIONS

The rehabilitation of anterior dental esthetics should involve interdisciplinary and facially driven planning for achieving pleasant long-term outcomes. Surgical crown lengthening is one of the most common periodontal surgery, which can be assisted by digital tools to improve surgical planning and follow-up.

CONCLUSION

The double guide for surgical crown lengthening allows the proper management of hard and soft tissues for achieving a predefined goal based on biological requirements and facially driven planning. In addition, the digital quality control allows the follow-up compared with the pre-operative condition and planned treatment plan.

CLINICAL SIGNIFICANCE

The use of digital tools allow the clinician to develop a facially driven planning with proper communication with the team and patient, leading to a shorter, more predictable, and less invasive surgical technique, reducing postoperative inflammation and increasing patient comfort.

The Accuracy and Reliability of Tooth Shade Selection Using Different Instrumental Techniques: An In Vitro Study

This study aimed to investigate and compare the reliability and accuracy of tooth shade selection in the model using 30 milled crowns via five methods: (1) digital single-lens reflex (DSLR) camera with twin flash (TF) and polarized filter (DSLR + TF), (2) DSLR camera with a ring flash (RF) and polarized filter (DSLR + RF), (3) smartphone camera with light corrector and polarized filter (SMART), (4) intraoral scanner (IOS), and (5) spectrophotometer (SPEC). These methods were compared with the control group or manufacturer’s shade. The CIE Lab values (L, a, and b values) were obtained from five of the methods to indicate the color of the tooth. Adobe Photoshop was used to generate CIE Lab values from the digital photographs. The reliability was calculated from the intraclass correlation based on two repetitions. The accuracy was calculated from; (a) ΔE calculated by the formula comparing each method to the control group, (b) study and control groups were analyzed by using the Kruskal–Wallis test, and (c) the relationship between study and control groups were calculated using Spearman’s correlation. The reliability of the intraclass correlation of L, a, and b values obtained from the five methods showed satisfactory correlations ranging from 0.732–0.996, 0.887–0.994, and 0.884–0.999, respectively. The ΔE from all groups had statistically significant differences when compared to the border of clinical acceptance (ΔE = 6.8). The ΔE from DSLR + TF, DSLR + RF, SMART, and SPEC were higher than clinical acceptance (ΔE > 6.8), whereas the ΔE from IOS was 5.96 and all of the L, a, and b values were not statistically significantly different from the manufacturer’s shade (p < 0.01). The ΔE of the DSLR + RF group showed the least accuracy (ΔE = 19.98), whereas the ∆E of DSLR + TF, SMART, and SPEC showed similar accuracy ∆E (ΔE = 10.90, 10.57, and 11.57, respectively). The DSLR camera combined with a ring flash system and polarized filter provided the least accuracy. The intraoral scanner provided the highest accuracy. However, tooth shade selection deserves the combination of various techniques and a professional learning curve to establish the most accurate outcome.