The accuracy of virtual setup in simulating treatment outcomes in orthodontic practice: a systematic review

OBJECTIVES

To evaluate the accuracy of virtual orthodontic setup in simulating treatment outcomes and to determine whether virtual setup should be used in orthodontic practice and education.

MATERIALS AND METHODS

A systematic search was performed in five electronic databases: PubMed, Scopus, Embase, ProQuest Dissertations & Theses Global, and Google Scholar from January 2000 to November 2022 to identify all potentially relevant evidence. The reference lists of identified articles were also screened for relevant literature. The last search was conducted on 30 November 2022.

RESULTS

This systematic review included twenty-one articles, where all of them were assessed as moderate risk of bias. The extracted data were categorized into three groups, which were: (1) Virtual setup and manual setup; (2) Virtual setup and actual outcomes in clear aligner treatment; (3) Virtual setup and actual outcomes in fixed appliance treatment. There appeared to be statistically significant differences between virtual setups and actual treatment outcomes, however the discrepancies were clinically acceptable.

CONCLUSION

This systematic review supports the use of orthodontic virtual setups, and therefore they should be implemented in orthodontic practice and education with clinically acceptable accuracy. However, high-quality research should be required to confirm the accuracy of virtual setups in simulating treatment outcomes.

Technology-enhanced simulation-based learning in orthodontic education: A scoping review

INTRODUCTION

Technology-enhanced simulations seem to be effective in dentistry, as they can support dental students to improve competencies in simulated environments. However, implementation of this technology in orthodontic education has not been reviewed.

OBJECTIVE

This scoping review aimed to comprehensively summarize the use of technology-enhanced simulations in orthodontic practice.

METHODS

A systematic search was conducted to identify literature on technology-enhanced simulation-based learning in orthodontic education published from 2000 to 2021. The search was conducted up to September 2021 to identify articles from Scopus, Embase, PubMed, ProQuest Dissertations & Theses Global, Google Scholar and the reference lists of identified articles.

RESULTS

The search identified 177 articles. Following the inclusion and exclusion criteria, 16 articles of 14 digital simulators were included in this review. The findings demonstrated an increasing use of technology-enhanced simulations in orthodontic education. They were designed in several formats, including three-dimensional virtual format, augmented reality, virtual reality, automaton, haptic, and scenario-based simulations. These simulations were implemented in varied areas of orthodontics including diagnosis and treatment planning, bracket positioning, orthodontic procedures, facial landmark, removable appliance and cephalometric tracing. Most included articles demonstrated the development process without outcome evaluation. Six studies provided outcome evaluations at reaction or learning levels. None of them provide the evaluation at behaviour and results levels.

CONCLUSION

Insufficient evidence has been generated to demonstrate the effectiveness of technology-enhanced simulations in orthodontic education. However, high-fidelity computer-based simulations together with robust design research should be required to confirm educational impact in orthodontic education.

Significance of Non-Statistically Significant Results in the Prediction of Oral Health-Related Quality of Life in Orthodontic Patients: A Survey Using Two Linking Questionnaires

Patients with a fixed orthodontic appliance may have difficulties in maintaining good oral health-related quality of life (OHRQoL), and evaluating self-perceived OHRQoL in orthodontic patients could be challenging for their orthodontists. Therefore, this research was conducted to investigate whether orthodontic postgraduates would accurately evaluate the OHRQoL of their patients. Two self-administered questionnaires were designed for patients to rate their OHRQoL and for their orthodontic postgraduates to evaluate them on OHRQoL. All pairs of patients and their orthodontic postgraduates were requested to independently complete the questionnaires. Pearson's correlation and multiple linear regression were performed to determine the relationships of the variables and to identify significant predictors on OHRQoL, respectively. There were 132 pairs of orthodontic patients and their residents who completed the questionnaires. There were no significant correlations between OHRQoL perceived by patients and evaluated by their orthodontic postgraduates in all aspects of treatment needs and dietary difficulties (p > 0.05). In addition, the regression model demonstrated no significant predictors for the self-perceived treatment needs and dietary difficulties of orthodontic patients. There seemed to be challenges for orthodontic postgraduates to evaluate their patients' oral health-related quality of life. Therefore, the OHRQoL measures should be increasingly implemented in orthodontic education and practice in order to enhance the concept of patient-centered care.

The implementation of PROMs/PREMs in the assessment of orthodontic treatment outcomes: A questionnaire survey

Objectives:

The aim of this study was to explore the impact of self-perceived treatment outcomes and experiences on psychological aspects, reflecting the importance of patient-reported outcome measures (PROMs) and patient-reported experience measures (PREMs) in orthodontic practice.

Materials and Methods:

A questionnaire was constructed using the PROMs/PREMs concepts. It contained five parts: “Demographic data”, “Self-perceived esthetics”, “Self-perceived functional concern”, “Satisfaction of treatment procedures”, and “Psychological aspect”. The questionnaire was piloted in five experts and 50 orthodontic patients to ensure its quality, using content validity, test-retest reliability, and Cronbach’s alpha. The validated version was provided to patients who had a complete fixed appliance orthodontic treatment. These data were analyzed using descriptive statistics, Mann-Whitney U test, and Spearman correlation. In addition, a multiple linear regression was used to analyze whether there were any influential factors on a psychological aspect. Statistical significance was taken at P < 0.05.

Results:

A total of 271 respondents completed the questionnaire. They tended to have positive perceptions toward the outcomes of orthodontic treatment. There was a significant difference in self-perceived esthetics between the male and female groups. Self-perceived esthetic and functional concerns as well as satisfaction of treatment procedures were found to have significant correlations with the psychological aspect. Sex and self-perceived esthetics were also found to be significant predictors of the psychological aspect.

Conclusion:

PROMs/PREMs should be considered as an important tool to assess treatment outcomes in orthodontic practice. There appeared to be significant impact of self-perceived esthetics on psychological aspects. Consequently, PROMs and PREMs should be introduced in orthodontic postgraduate programs to enhance the concept of patient-centered care in orthodontic practice.

Face Proportions, and Analysis of Maxillary Anterior Teeth and Facial Proportions in a Thai Population

Background:

Esthetics is the primary consideration for patients looking for prosthetic treatment. Determining the facial types of Thai populations is important because most studies conducted in Caucasian populations mention their facial types, and describe the gender comparisons, and GP of the teeth.

Objectives:

This study compared facial proportions, analyzed the maxillary anterior teeth proportions and determined the relationships between teeth with facial measurements using the Golden Proportion (GP) and Golden Standard (GS) in a Thai population.

Methods:

A total of 200 students (18-35 years) with well-aligned maxillary anterior teeth participated in this study. Face heights and widths were measured from the face using digital calipers and faces were classified as narrow, average, and broad. Teeth and face proportions were compared with GP and GS. One-way ANOVA was performed to compare maxillary anterior teeth proportions and facial proportions with different face types (α= 0.05). Pearson’s correlation was used (α= 0.05) to determine the correlation between facial proportion and teeth dimension among different facial types.

Results:

The findings showed 82.50% narrow face, 13.50% average, and 4% broad face among Thai subjects. No GP or GS was found in the face and anterior teeth, but teeth and face proportions other than GP and GS were found. No significant correlation was found between the Width of the Central Incisor (WCI) with interpupillary distance and alar width.

Conclusion:

In this study, the GP was not found in the facial and teeth proportion. The data obtained from this study may help to provide guidelines for prosthetic and orthodontic management and help to select the proper size and form of the maxillary anterior teeth to achieve proper esthetic outcomes in the Thai population.

Self-perceived Needs for Orthodontic Retreatment among Dental Students: A Qualitative Study

Aims

The aims of this research were to explore perceptions of Mahidol dental students toward orthodontic retreatment and to examine whether there were any influential factors in a dental school toward their decision to receive the retreatment.

Materials and Methods

Mahidol dental undergraduates who were requesting orthodontic retreatment were recruited into this research. A semi-structure interview with a topic guide was conducted to collect in-depth information. All responses were recorded using a digital voice recorder and transcribed using a verbatim transcription technique. The data were then analyzed using a framework analysis.

Results

The common reasons for requesting orthodontic retreatment among dental students were self-perceived esthetic and functional concerns. Knowledge and experiences of dental students could raise awareness of dental problems, so they were likely to detect even a small defect of their teeth. The students also worried if their dental problems were presented to patients or other dental students. In addition, although they were requesting for orthodontic retreatment, they felt quite worried with the complications they had learned from the dental program. The students also reported that these concerns could affect their psychological well-being.

Conclusion

Dental knowledge and experiences as well as surrounding people such as their peers and patients in a dental school seemed to have impact on awareness of dental problems and a decision to receive orthodontic retreatment.

The effect of LED photobiomodulation on the proliferation and osteoblastic differentiation of periodontal ligament stem cells: in vitro

BACKGROUND

The aim of this study was to investigate the influence of three different light-emitting diode (LED) wavelengths on the proliferation and osteoblastic differentiation of periodontal ligament stem cells (PDLSCs) in vitro.

METHODS

PDLSCs seeded on 96- and 24-well plates, for proliferation and osteoblastic differentiation, respectively, were irradiated daily by LED light with peak emission wavelengths of 630, 680, and 830 nm at constant energy densities of 3.5 J/cm². Cultures were grown for 8 days for the proliferation assay, 10 days for the alkaline phosphatase (ALP) assay, and 28 days for Alizarin red staining. Mitochondrial activity, ALP enzyme level, and the ability to form calcium phosphate deposits were measured and compared across cultures.

RESULTS

Results obtained from statistical analysis of the experimental data indicated that the rate of proliferation (P < 0.05) in 830-nm irradiated cultures were significantly higher than the control samples at day 6 and 8; whereas, for the 630- and 680-nm groups, test results showed lower proliferation rates at day 8. For osteoblastic differentiation, significantly greater mineralization than the control samples was detected in the red-light groups (630 and 680 nm) during the late differentiation period (P < 0.001), which was supported by a higher ALP activity of the 630- and 680-nm groups in the early stage (P < 0.01).

CONCLUSION

The results of this study demonstrate that the PDLSCs responded differently to specific LED wavelengths. For enhancing cellular proliferation, 830-nm LED irradiation was more effective. On the other hand, the wavelengths of 630 and 680 nm were better for stimulating osteoblastic differentiation.

Nepalese Esthetic Dental (NED) Proportion in Nepalese Population

Background Lots of studies on maxillary anterior teeth proportions have been studied in different populations in various countries, but no studies have been conducted in Nepal on the esthetic maxillary anterior teeth proportions. Objective The study was done to investigate the maxillary anterior teeth proportions in a Nepalese population. Teeth proportions in the total population were compared with golden proportion (GP) and golden standard (GS). Method A total of 150 Nepalese subjects were divided in three facial types; broad, average and narrow group. Maxillary anterior teeth were measured from dental casts using digital calipers. The perceived width ratios of lateral to central incisor (LI/CI) and canine to lateral incisor (CN/LI), ratios of mean central incisor length to 2 central incisor widths (CIL/2CIW), and actual width to length ratios (WLRs) (%) were calculated in each facial type and compared. Mean LI/CI, CN/LI and CIL/2CIW in total population were calculated and compared with GP (0.618), and mean WLRs in the total population were compared with GS (80%). All teeth proportions were compared among three facial types. One-sample t-test and one-way ANOVA were performed to analyze the data (α = 0.05). Result The LI/CI, CN/LI, CIL/2CIW and WLRs in three facial types showed no significant difference. The LI/CI, CN/LI and CIL/2CIW in the total population were 66%, 70% and 55% respectively, and were significantly different from GP. The WLRs for CI, LI and CN in the total population were 90%, 86% and 89% respectively and significantly differed from GS. These values were considered to constitute the Nepalese Esthetic Dental (NED) proportion. Conclusion No significant difference of maxillary anterior teeth proportions were observed among three facial types. Teeth proportions in the total population significantly differed from GP and GS. We propose the NED proportion as a guideline for dental treatment in the maxillary anterior region in Nepalese populations.

Evaluation of Stress Distribution on Implant-Retained Auricular Prostheses: The Finite Element Method

PURPOSE

The purpose of this study was to evaluate stress distribution around two craniofacial implants in an auricular prosthesis according to the removal forces. Three attachment combinations were used to evaluate the stress distribution under removal forces of 45 and 90 degrees.

MATERIALS AND METHODS

Three attachment designs were examined: (1) a Hader bar with three clips; (2) a Hader bar with one clip and two extracoronal resilient attachments (ERAs); and (3) a Hader bar with one clip and two Locators. The removal force was determined by means of an Instron universal testing machine with a crosshead speed of 10 mm/minute. All three designs were created in three dimensions using SolidWorks. The applied removal force and the models were then introduced to finite element software to analyze the stress distribution.

RESULTS

The angle of removal force greatly affected the magnitude and direction of stress distribution on the implants. The magnitude of stress under the 45-degree removal force was higher than the stress at 90 degrees. The combination of the 1,000-g retention clip and 2,268-g retention Locator exhibited the highest stress on the implant flange when the removal force was applied at 45 degrees.

CONCLUSION

The removal angle greatly influences the amount of force and stress on the implants. Prosthodontists are encouraged to inform patients to remove the prosthesis at 90 degrees and, if possible, use a low-retentive attachment to reduce stress.

Comparison of friction forces between stainless orthodontic steel brackets and TiNi wires in wet and dry conditions

In sliding mechanics, frictional force is an important counter-balancing element to orthodontic tooth movement, which must be controlled in order to allow application of light continuous forces. The purpose of this study was to compare the frictional forces between a stainless steel bracket and five different wire alloys under dry and wet (artificial saliva) conditions. TiNi, TiNiCu, TiNiCo, commercial wires A and commercial wires B with equal dimensions of 0.016×0.022'' were tested in this experiment. The stainless steel bracket was chosen with a slot dimension of 0.022''. Micro-hardness of the wires was measured by the Vickers micro-hardness test. Surface topography of wires was measured by an optical microscope and quantified using surface roughness testing. Static and kinetic friction forces were measured using a custom-designed apparatus, with a 3-mm stretch of wire alloy at a crosshead speed of 1mm/min. The static and dynamic frictions in the wet condition tended to decrease more slowly than those in the dry condition. Therefore, the friction of TiNiCu and commercial wires B would increase. Moreover, these results were associated with scarred surfaces, i.e. the increase in friction would result in a larger bracket microfracture. From the results, it is seen that copper addition resulted in an increase in friction under both wet and dry conditions. However, the friction in the wet condition was less than that in dry condition due to the lubricating effect of artificial saliva.

The effect of light-emitting diode irradiation at different wavelengths on calcification of osteoblast-like cells in 3D culture

This study aimed to investigate the effect of four different light-emitting diode (LED) wavelengths on calcification and proliferation of osteoblast-like cells in vitro. MC3T3-E1 cells were seeded within three-dimensional collagen scaffolds and irradiated daily by LED light with peak emission wavelengths of 630-, 680-, 760- and 830-nm at constant fluency of 3.1 J/cm(2) (irradiance intensity 2 mW/cm(2)). Cultures were measured for calcium content at day 0, 7, 14, 21, 28, 35 and 42. The significant enhancement in calcium content was observed at the early stage of culture (days 7 and 14) (p<;0.05). After that, the calcium content of irradiated groups was similar to that of the controls group. This suggests the transient effect of light irradiation on osteoblastic cell calcification. Only 680-nm irradiated samples revealed a significant enhancement of calcium content until the late stages of culture (from days 21 to 42) (p<;0.001). The cyclin D mRNA expression that was investigated 3 hours after stimulation at day3 also show that the 680-nm LED irradiation can enhance cyclin D expression more than others. For enhancing bone mineralization, LED irradiation at the 680-nm is more effective than those at 630-, 760- and 830-nm. Further studies should be investigated in order to obtain the most effective parameters of LLLI on bone regeneration in clinical setting.

Photobiomodulation accelerates orthodontic alignment in the early phase of treatment

Background

Numerous strategies have been proposed to decrease the treatment time a patient requires in orthodontic treatment. Recently, a number of device-accelerated therapies have emerged in orthodontics. Photobiomodulation is an emerging area of science that has clinical applications in a number of human biological processes. The aim of this study was to determine if photobiomodulation reduces the treatment time in the alignment phase of orthodontic treatment.

Methods

This multicenter clinical trial was performed on 90 subjects (73 test subjects and 17 controls), and Little's Index of Irregularity (LII) was used as a measure of the rate of change of tooth movement. Subjects requiring orthodontic treatment were recruited into the study, and the LII was measured at regular time intervals. Test subjects used a device which produced near-infrared light with a continuous 850-nm wavelength. The surface of the cheek was irradiated with a power density of 60 mW/cm² for 20 or 30 min/day or 60 min/week to achieve total energy densities of 72, 108, or 216 J/cm², respectively. All subjects were fitted with traditional orthodontic brackets and wires. The wire sequences for each site were standardized to an initial round alignment wire (014 NiTi or 016 NiTi) and then advanced through a progression of stiffer arch wires unit alignment occurred (LII < 1 mm).

Results

The mean LII scores at the start of the clinical trial for the test and control groups were 6.35 and 5.04 mm, respectively. Multi-level mixed effect regression analysis was performed on the data, and the mean rate of change in LII was 0.49 and 1.12 mm/week for the control and test groups, respectively.

Conclusions

Photobiomodulation produced clinically significant changes in the rates of tooth movement as compared to the control group during the alignment phase of orthodontic treatment.

Growth-associated protein-43 immunohistochemical and ultrastructural changes in jaw muscle spindles of the rat following loss of occlusion

The effects of complete loss of occlusion on the structural and functional status of these muscle spindles were investigated by immunohistochemistry either for protein gene product 9.5 (PGP 9.5) or growth-associated protein-43 (GAP-43) by light and electron microscopy. All the upper molars of 4-week-old Wistar rats were extracted and the erupted portions of the upper and lower incisors of the same animals were cut-off at the level of the interdental papilla every other day. In a control group, immunoreactivity for GAP-43 was positive in the developing annulospiral endings of 2-week-old rats, but was not detected in any of the muscle spindles after 3 weeks of age. At 4 weeks of age, the PGP 9.5 immunostained spindles had well-differentiated annulospiral endings. Ultrastructurally, these afferent endings showed lenticular or circular profiles in cross-sections, and were differentially indented into the intrafusal-fibres. The inner surfaces of the terminals formed rather smooth myoneural junctions, while the outer surfaces were covered only by basal lamina continuous with that of the underlying intrafusal muscle fibres. After the experimental elimination of occlusal contact, GAP-43 immunoreactivity reappeared in some nerve endings of muscle spindles by 3 days, and persisted for at least 28 days. During this period, the afferent-terminals exhibited various fine structural abnormalities such as irregular outlines and invaginated neuromuscular interfaces. Some sensory-terminal (ST) profiles were completely engulfed by intrafusal-fibres. However, GAP-43 expression and ultrastructural alterations became undetectable within a week of the end of incisal cutting and the recovery of incisal-contact. These data indicate that remodelling of nerve terminals in muscle spindles, as assessed by GAP-43 expression and ultrastructural changes, occurs soon after a loss of occlusion, and ceases if incisal-contact is restored. It is concluded that possible changes in jaw muscle function, as well as a sudden loss of proprioceptive sensory input from the periodontal mechanoreceptors of molars and incisors, induce the structural reorganisation of nerve terminations in jaw muscle spindles that is associated with the appearance and disappearance of GAP-43 immunoreactivity.