Gingival enlargement in orthodontic patients: Effect of treatment duration

Longitudinal Microbiome Changes in Supragingival Biofilm Transcriptomes Induced by Orthodontics

INTRODUCTION

Common oral diseases are known to be associated with dysbiotic shifts in the supragingival microbiome, yet most oral microbiome associations with clinical end points emanate from cross-sectional studies. Orthodontic treatment is an elective procedure that can be exploited to prospectively examine clinically relevant longitudinal changes in the composition and function of the supragingival microbiome.

METHODS

A longitudinal cohort study was conducted among 24 adolescent orthodontic patients who underwent saliva and plaque sampling and clinical examinations at time points: before fixed appliance bonding and at 1, 6, and 12 wk thereafter. Clinical indices included bleeding on probing (BOP), mean gingival index (GI), probing depths (PDs), and plaque index (PI). To study the biologically (i.e., transcriptionally) active microbial communities, RNA was extracted from plaque and saliva for RNA sequencing and microbiome bioinformatics analysis. Longitudinal changes in microbiome beta diversity were examined using PERMANOVA tests, and the relative abundance of microbial taxa was measured using Kruskal-Wallis tests, Wilcoxon rank-sum tests, and negative binomial and zero-inflated mixed models.

RESULTS

Clinical measures of oral health deteriorated over time-the proportion of sites with GI and PI ≥1 increased by over 70% between prebonding and 12 wk postbonding while the proportion of sites with PD ≥4 mm increased 2.5-fold. Streptococcus sanguinis, a health-associated species that antagonizes cariogenic pathogens, showed a lasting decrease in relative abundance during orthodontic treatment. Contrarily, caries- and periodontal disease-associated taxa, including Selenomonas sputigena, Leptotrichia wadei, and Lachnoanaerobaculum saburreum, increased in abundance after bonding. Relative abundances of Stomatobaculum longum and Mogibacterium diversum in prebonding saliva predicted elevated BOP 12 wk postbonding, whereas Neisseria subflava was associated with lower BOP.

CONCLUSIONS

This study offers insights into longitudinal community and species-specific changes in the supragingival microbiome transcriptome during fixed orthodontic treatment, advancing our understanding of microbial dysbioses and identifying targets of future health-promoting clinical investigations.

KNOWLEDGE TRANSFER STATEMENT

Bonding braces was associated with subsequent changes in the oral microbiome characterized by increases in disease-associated species, decreases in health-associated species, and worsened clinical measures of oral health.

The orthodontic treatment and the periodontal status of patients

OBJECTIVE

Aim: To review and analyze modern professional literature on the impact of orthodontic treatment of maxillofacial anomalies on the periodontal status of patients, in particular, the subsiqent pathogenetic mechanisms of the development of periodontal diseases in this category of patients.

PATIENTS AND METHODS

Materials and Methods: Bibliometric and analytical methods were used data from international scientific sources in the field of studying the impact of orthodontic treatment on the state of periodontal tissues were used. Conclusions: Patients undergoing orthodontic treatment need the increased attention to the state of periodontal tissues and regular high-quality both professional and individual oral hygiene. A comprehensive approach to treatment and preventive measures for periodontal diseases, taking into account all pathogenetic links of their development in this category of patients, aims not only to keep the periodontium healthy, but also to ensure successful completion of orthodontic treatment. Taking into account consideration the periodontal status of patients allows individual correction of the treatment plan to increase its clinical effectiveness both in the early and in the long term.

A Retrospective Histological Study on Palatal and Gingival Mucosa Changes during a Rapid Palatal Expansion Procedure

The most common inflammatory reactions in the oral mucosa are found at the gingival level. The treatment of these inflammations requires, first of all, the removal of the causative factor; often, this maneuver is sufficient. The aim of this retrospective study was to evaluate clinical and histopathological changes that occur in terms of gingival and palatal mucosa enlargement during palatal expansion treatment and their evolution during treatment. Twenty-five (n = 25) research participants, aged between thirteen and twenty-six years old, were examined in this retrospective study. At the end of the treatment, fragments of tissue from the affected level were obtained via incisional biopsy and sent to the histopathology laboratory for a specialized examination. The changes identified were specific to mechanical traumatic injuries, thus excluding hyperplasia from other etiologies (infectious, tumoral, or non-mechanical traumatic). The examined fragments showed hyperplasia. The histopathological examination revealed the mechanical character of the lesion, strengthening the causal relationship between the insertion of the expander and the occurrence of hyperplasia of the palatal mucosa. The type of palatal expander influenced the degree of inflammation, with the severity of hyperplasia being more pronounced in the case of mini-implant-anchored rapid palatal expander (MARPE) usage than in the case of tooth-borne rapid palatal expander (RPE) usage. The analysis of the distance between the expander and the palatal mucosa did not provide conclusive results; the incidence and severity of the reaction were variable in patients with the same distance between the expander and the palatal or gingival mucosa.

Effectiveness of Waterpik® for oral hygiene maintenance in orthodontic fixed appliance patients: A randomised controlled trial

OBJECTIVE

To establish whether the use of a WaterPik® alongside a manual toothbrush (WaterPik® + MTB) is more effective for maintaining oral hygiene compared to the use of a manual toothbrush alone (MTB) in patients wearing fixed orthodontic appliances.

DESIGN

A single-centre, two-arm, parallel-group, single-blind, randomised controlled clinical trial with a 1:1 allocation ratio.

SETTING

Orthodontic department at York Hospital, York Teaching Hospitals NHS Foundation Trust, UK.

PARTICIPANTS

A total of 40 fit and well participants, aged 10-20 years, being treated with upper and lower fixed orthodontic appliances.

METHODS

Participants were randomly allocated, using stratified block randomisation, to the control group (MTB) or intervention group '(Waterpik® + MTB)'. Plaque, gingival and interdental bleeding indices were recorded at baseline, 8 weeks, 32 weeks and 56 weeks. A generalised linear mixed model was used to assess differences between groups.

RESULTS

An interim analysis of results was performed with 40 patients recruited and 85% of data collected. The overall mean differences between the groups were as follows: plaque index = 0.199 (P = 0.88, 95% confidence interval [CI] -0.24 to 0.27); gingival index = -0.008 (P = 0.94, 95% CI -0.22 to 0.20); and interdental bleeding index = 5.60 (P = 0.563, 95% CI -13.22 to 24.42). No statistical difference between the two groups was found for any variable. The trial was stopped at this point.

CONCLUSIONS

In terms of oral hygiene, our study did not find evidence to support the claim of benefit of using a Waterpik® in addition to a manual toothbrush for patients wearing fixed orthodontic appliances.

RANK-RANKL-OPG expression after gingival mesenchymal stem cell hypoxia preconditioned application in an orthodontic tooth movement animal model

Background

The expression of receptor activator of Nuclear Factor Kappa Beta (RANK) and its ligand (RANKL), as well as osteoprotegrin (OPG), in the alveolar bone (AB), may improve bone remodeling during orthodontic tooth movement (OTM). It is hypothesized that hypoxia-preconditioned gingival mesenchymal stem cells (GMSC) may be more effective than normoxia-preconditioned GMSC in this regard. This study aims to investigate the expression of RANK, RANKL, and OPG in the compression and tension sides of AB after allogeneic administration of GMSC that were normoxia or hypoxia-preconditioned in rabbits (Oryctolagus cuniculus) undergoing OTM.

Methods

Twenty-four healthy young male rabbits were divided into two groups: T1, which underwent OTM and received normoxia-preconditioned GMSC, and T2, which underwent OTM and received hypoxia-preconditioned GMSC. A ligature wire was attached to the mandibular first molar and connected to a 50 g/mm2 closed coil spring, exerting force on the central incisor and left mandibular molar of the experimental animals. After 24 h of OTM, either normoxia- or hypoxia-preconditioned GMSC were injected into the gingiva of the samples in a single dose of 20 μl of phosphate-buffered saline (PBS). All samples were sacrificed on days 7, 14, and 28, and immunohistochemistry was performed to analyze the expression of RANK, RANKL, and OPG on the tension and compression sides.

Results

The expressions of RANK-RANKL-OPG in the alveolar bone of the compression and tension sides were significantly different during the 14-day period of OTM following allogeneic administration of GMSC that were normoxia or hypoxia-preconditioned (p < 0.05).

Conclusion

The expression of RANK-RANKL was significantly increased on the compression side of the alveolar bone during OTM after the administration of hypoxia-preconditioned allogeneic GMSC but not on the tension side. Conversely, RANKL-OPG expression was enhanced on the tension side but not on the compression side, as observed through immunohistochemical analysis in vivo.

Management of Orthodontic-Induced Gingival Enlargement: A Case Report

The aetiology of gingival enlargement (GE) is highly distinct. Plaque-induced gingival inflammation can be the sole reason for gingival enlargement. Poor dental hygiene, irritation from anatomical variations, and ineffective restorative and orthodontic appliances are all factors that encourage the formation and retention of plaque. In the given case report, a case of gingival enlargement associated with an orthodontic appliance of a 23-year-old female patient referred from the Department of Orthodontics was reported to the Department of Periodontics. Under local anaesthesia, the excess gingival tissue is removed using a scalpel by gingivectomy and gingivoplasty procedures. The gingivectomy and gingivoplasty procedures using a scalpel gave the best results in the orthodontic treatment associated with gingival enlargement. After achieving hemostasis, the periopack (Coe-pack) was placed to assist healing by protecting the tissue. The above case report can appreciate the gingival tissue covering almost half of the crown, causing plaque retention and presenting the patient with aesthetic concerns. After the surgical procedure, a proper gingival contour eliminates suprabony pockets and provides pleasant esthetics. This case report demonstrates that eliminating the suprabony pockets by gingivectomy and gingivoplasty leads to a physiologic gingival contour and eliminates plaque retention. The conventional scalpel gingivectomy procedure is an effective form of treatment when indicated.

Vibrational Force on Accelerating Orthodontic Tooth Movement: A Systematic Review and Meta-Analysis

This study aimed to systematically gather and analyze the current level of evidence for the effectiveness of the vibrational force in accelerating orthodontic tooth movement (OTM). This systematic review was conducted using three electronic databases: Scopus, PubMed, and Google Scholar until March 2022. The search was done through the following journals: European Journal of Orthodontics, American Journal of Orthodontics and Dentofacial Orthopedics, The Angle Orthodontist, Progress in Orthodontics, and Seminars in Orthodontics. Human or animal studies that have evaluated the effect of vibrational force on the rate of OTM were selected. A meta-analysis was performed for the rate of canine movement per month. Database research, elimination of duplicate studies, data extraction, and risk of bias assessment were performed by authors independently and in duplication. A fixed and random-effect meta-analysis was performed to evaluate the effect of vibrational forces. A total of 19 studies (6 animal and 13 human studies) that met the inclusion criteria were included. Meta-analysis was performed based on four human clinical trials. Three out of four studies showed no significant difference in the rate of canine movement between vibrational force and control groups. The limitation of this study was the small sample size and significant heterogeneity among the studies. Although vibrational forces have been shown to accelerate OTM in experimental studies, the results are inconsistent in clinical studies. The inability to apply desired peak load to the targeted teeth may be the main factor in inconsistent clinical outcomes.

Complications and treatment errors involving periodontal tissues related to orthodontic therapy

In this review, typical clinical complications involving periodontal tissues are illustrated that can be encountered in conjunction with orthodontic therapy (OT). Special considerations are given for various clinical scenarios, such as the patient presenting in periodontal health, with periodontitis, or with mucogingival conditions. While some of the complications are seen as common side effects of OT, other, more severe, problems that could have been avoided may be viewed as treatment errors. Recommendations are made on how to prevent these complications, based on the currently available evidence, on clinical practice guidelines, and on expert opinion. In conclusion, while there are several areas in which OT can have unwanted adverse effects on periodontal/mucogingival conditions, there is also great potential for synergies, offering opportunities for close cooperation between the two specialties (periodontics and orthodontics) for the benefit of patients affected by tooth malpositioning and/or periodontal or mucogingival problems.

Effects of Laser Therapy on Periodontal Status in Adult Patients Undergoing Orthodontic Treatment

Orthodontic treatment with fixed devices should only be indicated in case of a stable, non-active periodontal disease status. Throughout orthodontic treatment, a careful assessment of the periodontal status is advised. Due to its anti-inflammatory and antimicrobial effects, laser therapy is frequently used as an adjunct to classic periodontal therapy. The aim of this study was to evaluate the advantages and limitations of the use of laser therapy on periodontal status during orthodontic treatment. Throughout the 9 months during which this placebo-controlled, single-blind clinical trial was conducted, 32 patients were included in the study, divided into two groups: microscope “+” (patients who observed the bacteria within the dental plaque-sample examination on the screen of a dark-field microscope in real time) and microscope “−” (patients who did not see the oral pathogens using a dark-field microscope). For all patients, using the split-mouth study design, laser therapy was applied to one hemiarch (HL), whereas the other hemiarch received treatment without active light (HC). After one month, by analyzing the main indicators of periodontal health status, we found that the plaque index (PI) and bleeding on probing (BOP) values were significantly decreased after receiving treatment (for PI: HL-p = 0.0005, HC-p = 0.0297; for BOP: HL-p = 0.0121, HC-p = 0.0236), whereas the probing-depth (PD) values remained almost the same as before treatment (HL-p = 1.5143; HC-p = 1.4762). Conclusions: The use of the dark-field microscope proved to be beneficial in sensitizing patients to the presence of bacteria in the oral cavity and motivated them to strictly follow the rules of oral hygiene. Laser treatment can be a valuable aid in periodontal therapy, but only in adjunction with mechanical therapy.

Motivation of Adult Patients with Orthodontic Treatment in Maintaining Oral Hygiene

Background: In the last decades, adult patients require orthodontic treatment as a therapeutic method in an increasing percentage. This treatment has a lot of benefits, but unfortunately it also presents a number of complications and risks, among which favoring the accumulation of bacterial plaque is the most concerning.

Aim of the study: In this study we aimed to evaluate the effectiveness of using the dark-field microscope as a method of motivating adult patients with orthodontic treatment in maintaining a proper oral hygiene.

Material and methods: Thirty-six patients were selected based on the inclusion and exclusion criteria. At time T0, patients were divided into two groups: Group 1–microscope and Group 2 – control, in such a way that the groups were as homogeneous as possible. Dental plaque samples were collected and analyzed under a dark field microscope in the presence of the patient for subjects from Group 1 but not Group 2. All patients were then instructed on oral hygiene techniques. The following periodontal indices were recorded of each patient: plaque index (PI), index of bleeding on probing (BOP), probing depth (PD) – at T0 and T1 (after one month).

Results: Comparing the PI and BOP values before (T0) and after treatment (T1), statistically significant results were detected (PI: p = 0.0020, BOP: p = 0.0297), which denotes that patients who observed the bacterial load of their dental plaque in real time using the dark-field microscope had a better oral hygiene and lower values of periodontal health indices. Regarding the PD index, the difference between time T0 and T1 was not statistically significant (p = 1.4762).

Conclusions: During the orthodontic treatment, adult patients often present gingival inflammation caused by improper hygiene. The use of the dark-field microscope is effective in motivating patients regarding the rules of maintenance of a proper oral hygiene.

Effect of Extending Corticotomy Depth to Trabecular Bone on Accelerating Orthodontic Tooth Movement in Rats

Corticotomy is a surgical procedure that induces injury to the cortical bone to accelerate tooth movement. This study aimed to increase the depth of corticotomy to the trabecular bone and to evaluate the amount and rate of tooth movement and alveolar bone changes in response to various degrees of cortical and trabecular bone injury. Seventy-eight male Wistar rats were randomly divided into four groups based on procedure used: (1) baseline control group of orthodontic tooth movement (OTM) only; (2) OTM + 4 corticotomies (CO); (3) OTM + 4 osteotomies (OS); and (4) OTM + 16 CO. A closed-coil nickel–titanium spring was placed to move the maxillary first molar mesially with a 10 g force. On days 0, 7, 14, and 21, alveolar bone alteration and tooth movement were measured using microcomputed tomography. Significant tooth movement was related to the number and the depth of the perforations. The OTM + 16 CO group showed a greater amount and rate of tooth movement than the OTM + 4 CO group. When osteotomy and corticotomy were compared with the same volume of bone removed, the OTM + 4 OS group had a faster rate of tooth movement than the OTM + 16 CO group during the first week, with significantly reduced bone volume. However, no significant difference was observed in the amount of tooth movement between the OTM + 4 OS and OTM + 16 CO groups at the end of the study. Extending the depth of corticotomy to trabecular bone increased the amount of tooth movement by accelerating the induction and completion of bone remodeling, which accelerated the rate of tooth movement during the initial stage.

Gingival recession in mandibular anterior teeth in patients with Class II malocclusion treated with elastics and Twin Force appliance

INTRODUCTION

This study aimed to compare the early results of gingival recession in patients with Class II malocclusion treated with Class II intermaxillary elastics and the Twin Force appliance.

METHODS

The sample comprised 55 patients with Class II malocclusion treated without extraction and divided into 2 groups. Group 1 consisted of 23 patients treated with fixed appliances and Class II elastics, with mean initial age of 15.41 ± 5.65 years and a mean treatment time of 3.11 ± 0.91 years. Group 2 consisted of 32 patients treated with fixed appliances and the Twin Force mandibular protraction appliance, with a mean initial age of 18.45 ± 6.63 years and a mean treatment time of 3.17 ± 1.59 years. Dolphin software measured gingival recession in initial and final intraoral photographs. Initial and final lateral cephalograms were used to measure the position of the mandibular incisors. Intragroup and intergroup comparisons were performed by dependent and independent t tests, respectively.

RESULTS

In both groups, there was no significant increase in gingival recession with orthodontic treatment, and there was significant protrusion and buccal inclination of the mandibular incisors. When changes with treatment were compared between the groups, there was no statistically significant difference in gingival recession and mandibular incisor position.

CONCLUSIONS

There was no significant increase in gingival recession immediately after orthodontic treatment performed with intermaxillary elastics and the Twin Force appliance.

In vivo investigation of gingival health and oxidative stress changes in patients undergoing orthodontic treatment with and without fluoride use

Background and Aims:

We aimed to investigate gingival index changes and oxidative stress in orthodontic patients with and without the use of fluoridated agents over a 6-month period.

Materials and Methods:

Ninety subjects divided into three groups (30 untreated controls, 30 with fixed appliances using nonfluoridated toothpaste, and 30 with fixed appliances using fluoridated toothpastes and mouthwashes ) comprised the sample. The Loe gingival index was used to rank gingival health at four specific time periods in the groups to determine differences (before, at 7 days, 30 days, and 6 months). Gingival crevicular fluid was evaluated for cytokines (interleukin [IL]-1β and tumor necrosis factor [TNF]-α) to determine differences in oxidative status between the groups.

Results:

Controls showed no changes in gingival index throughout the 6-month observation period. There was a deterioration in gingival health in both the fluoridated and nonfluoridated groups till 6 months. IL-1β levels in the fluoridated group increased from the 7^th day, reached a peak at 30 days, and remained slightly elevated at 6 months. The nonfluoridated group also showed elevated levels at all tested time periods, but levels were lower as compared to fluoridated samples. The differences in IL-1β values between the fluoridated and nonfluoridated treated groups were significant. TNF-α levels in the three groups also showed a similar pattern with elevated levels seen in both the treated groups at the 7^th, 30-day, and 6-month periods. The fluoridated group showed the highest levels at three time periods which was statistically significant.

Conclusions:

Gingival health of subjects treated with fixed orthodontic appliances deteriorated from appliance placement till a 6-month time period. Cytokines such as IL-1β and TNF-α associated with oxidative stress during orthodontic treatment increased in both the treated groups, with higher levels in fluoridated subjects. Long-term consequences of oxidative stress changes need further investigation.

Comprehensive evaluation of factors that induce gingival enlargement during orthodontic treatment: A cross-sectional comparative study

Background

Gingival enlargement (GE) is one of the most common soft tissue problems encountered during fixed orthodontic treatment. Aims: This study aimed to evaluate the factors affecting GE in adolescents and young adults, compared with their normal peers.

Subjects and Methods

This is a cross-sectional comparative study. The sample consisted of 329 subjects (ages 10-30 years) of both genders, which was divided into four main groups: The control group (G0) with no orthodontic treatment; subjects who underwent orthodontic treatment were divided according to treatment duration into G1 (4-12 months), G2 (13-24 months), and G3 (>24 months). The clinical examinations included the level of debris, calculus (simplified oral hygiene), and GE indices. Regression analyses were used to assess the GE association in all the studied groups.

Results

The mean GE score increased significantly with increased treatment duration (0.42 ± 0.29 for G0 and 1.03 ± 0.52 for G3). GE scores of the lower arch were significantly higher in the anterior segment than in the posterior segment among all treatment groups. Regression analysis revealed that gender, age, oral hygiene, and treatment duration had a significant effect on GE (P < 0.05), while angle classification, overjet, overbite, treatment stage, bracket type, and therapeutic extraction did not show significant associations (P > 0.05).

Conclusion

Gender, age, oral hygiene, and treatment duration were the most important risk factors for GE during fixed orthodontic treatment.

Metal ions leachables from fake orthodontic braces incubated in simulated body fluid

Background

The demand for fake braces usage in Southeast Asia are increasing but lack of certification and information on fake braces as medical devices from regulated bodies raised a concern towards its safety. The aim of this study was to determine the types of metal ion leachable from removable fake braces based on heavy metal ions present in metallic materials, immersed in simulated body fluid (SBF) and analysed using inductively coupled plasma atomic emission spectroscopy.

Methods

Three sets of fake braces and one control were dissembled to only their brackets and archwires and immersed separately in SBF. They were placed in an incubator shaker at a temperature of 37 °C at 50 rpm. A 3.0 ml measurement of SBF was taken out from the sample containers at days 7, 14 and 28 and kept at − 20 °C for further analysis. Data were analysed using SPSS version 26.0 (IBM, Armonk, USA) (P < 0.05). Descriptive and one-way ANOVA analyses with Bonferroni post hoc tests were used to assess the significant differences between the metal ions released in SBF from the control samples and fake braces.

Results

All 23 elements under investigation except Si ions were detected from the control samples and fake braces. There were significant increased K ions and reduced levels of Mg ions from the fake archwires and brackets. Most ions released were less than 10 mg/L (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd, Pb, Al) or 1 mg/L (Li, Ba) into the SBF medium.

Conclusion

There were significant release of Ca and K ions from the fake samples. Elements such as Li, Ba, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, Cd and Sb had increased in concentration at day 7 and the concentration plateaued until day 28.

Effect of micro-osteoperforations on the gene expression profile of the periodontal ligament of orthodontically moved human teeth

OBJECTIVES

This study aimed to evaluate the effect of micro-osteoperforations (MOPs) on the gene expression profile of the periodontal ligament (PDL) of orthodontically moved teeth.

MATERIALS AND METHODS

Fifteen participants were randomly assigned into two groups: tooth movement only (Tr1, n = 7) and tooth movement supplemented with MOPs (Tr2, n = 8). In each subject, orthodontic tooth movement (OTM) was performed on premolar in one side, while no force was applied on contralateral premolar (Unt, n = 15). Seven days after loading, premolars were extracted for orthodontic reasons. RNA extraction from PDL and subsequent RNA-sequencing were performed. False discovery rates (Padj < 0.05) and log2 fold change (+ / - 1.5) thresholds were used to identify sets of differentially expressed genes (DEGs) among the groups. DEGs were analyzed with gene ontology enrichment, KEGG, and network analysis.

RESULTS

Three hundred thirty-one DEGs were found between Tr1 and Unt, and 356 between Tr2 and Unt. Although, there were no significantly DEGs between Tr2 and Tr1, DEGs identified exclusively in Tr1 vs. Unt were different from those identified exclusively in Tr2 vs. Unt. In Tr1, genes were related to bone metabolism processes, such as osteoclast and osteoblast differentiation. In Tr2, genes were associated to inflammation processes, like inflammatory and immune responses, and cellular response to tumor necrosis factor.

CONCLUSIONS

MOPs do not significantly alter the PDL gene expression profile of orthodontically moved human teeth. This study provides for the first time evidence on the whole PDL gene expression profiles associated to OTM in humans. Novel biomarkers for OTM are suggested for additional research. Clinical relevance The identified biomarkers provide new insights into the molecular mechanisms that would occur when OTM is supplemented with MOPs. These markers are expected to be useful in the near future for the application of personalized strategies related to the OTM.

Machine learning in dental, oral and craniofacial imaging: a review of recent progress

Artificial intelligence has been emerging as an increasingly important aspect of our daily lives and is widely applied in medical science. One major application of artificial intelligence in medical science is medical imaging. As a major component of artificial intelligence, many machine learning models are applied in medical diagnosis and treatment with the advancement of technology and medical imaging facilities. The popularity of convolutional neural network in dental, oral and craniofacial imaging is heightening, as it has been continually applied to a broader spectrum of scientific studies. Our manuscript reviews the fundamental principles and rationales behind machine learning, and summarizes its research progress and its recent applications specifically in dental, oral and craniofacial imaging. It also reviews the problems that remain to be resolved and evaluates the prospect of the future development of this field of scientific study.

Comparison of tooth movement and biological response resulting from different force magnitudes combined with osteoperforation in rabbits

OBJECTIVE

To compare tooth movement rate and histological responses with three different force magnitude designs under osteoperforation in rabbit models.

METHODOLOGY

48 rabbits were divided into three groups: Group A, Group B, and Group C, with traction force of 50 g, 100 g, 150 g, respectively. Osteoperforation was performed at the mesial of the right mandibular first premolar, the left side was not affected. One mini-screw was inserted into bones between two central incisors. Coil springs were fixed to the first premolars and the mini-screw. Tooth movement distance was calculated, and immunohistochemical staining of PCNA, OCN, VEGF, and TGF-β1 was analyzed.

RESULTS

The tooth movement distance on the surgical side was larger than the control side in all groups (P<0.01). No significant intergroup difference was observed for the surgical side in tooth movement distance among the three groups (P>0.05). For the control side, tooth movement distance in Group A was significantly smaller than Groups B and C (P<0.001); no significant difference in tooth movement distance between Group B and Group C was observed (P>0.05). On the tension area of the moving premolar, labeling of PCNA, OCN, VEGF and TGF-β1 were confirmed in alveolar bone and periodontal ligament in all groups. PCNA, OCN, VEGF and TGF-β1 on the surgical side was larger than the control side in all groups (P<0.001).

CONCLUSION

Osteoperforation could accelerate orthodontic tooth movement rate in rabbits. Fast osteoperforation-assisted tooth movement in rabbits was achieve with light 50 g traction.

Protein carbonylation associated with nickel liberation in orthodontic gingival overgrowth

OBJECTIVE

To determine nickel levels and their impact on protein carbonylation in gum samples from patients with gingival overgrowth by orthodontic treatment.

DESIGN

A retrospective observational study with 33 patients divided into three groups. Group 1 patients with gingival overgrowth by orthodontic appliances; group 2 patients without gingival overgrowth but with a history of orthodontic treatment; group 3 patients without overgrowth and history of orthodontic appliances. Nickel level in gingiva samples was measured by atomic absorption while protein carbonylation was determined by Western Blot. Furthermore, three proteins were identified in carbonylated protein bands by mass spectrometry.

RESULTS

Statistically significant differences (p < 0,05) in tissue nickel levels among groups were established (nickel levels group 1: 1.33 ± 1.52; group 2: 0.33 ± 0.44; group 3: 0.20 ± 0.22 μg Ni/g tissue). Protein carbonylation was higher in patients with gingival enlargement (group 1) and history of appliance use (group 2) than controls (group 3). It was observed that band A of the Western blots presented the highest intensity (Rf 0.23) with an average intensity of 4.133.830 ± 1.958.569 for group 1; 4.420.146 ± 1.594.679 for group 2 and 2.110. 727 ± 1.640.721 for group 3. Also, the proteins Teneurin-4, Bromodomain adjacent to zinc finger domain protein 2B, Lysine-specific demethylase 5B, and Serum albumin, were identified from oxidized bands.

CONCLUSIONS

The gum of patients with gingival overgrowth by orthodontic appliances contains higher nickel residues and carbonylation of its proteins.

Prioritization of predisposing factors of gingival hyperplasia during orthodontic treatment: the role of amount of biofilm

Background

The mechanism of gingival growth that may occur during fixed orthodontic treatment is not yet fully understood and the amount of dental plaque is often incriminated. The objective of this study was to evaluate the prevalence of gingival growth during multi-attachment orthodontic treatment and to prioritize its predicting factors, especially the quantity of biofilm.

Methods

This comprehensive cross-sectional descriptive study was conducted on orthodontic patients aged 9 to 30 years, in good health, treated by a fixed appliance. Periodontal clinical parameters such as plaque index, gingival index, probing pocket depth, periodontal phenotype and gingival enhancement index were recorded. Likewise, the brushing habits and the date of the last scaling were noted. The orthodontic parameters studied were the duration of the treatment, the type of bracket, the alloys used for the arches and the type of ligatures. Descriptive statistics were carried out, and variables presenting p value < 0.25 were included in a multivariate analysis to calculate the Odds Ratio (OR) of gingival enlargement”.

Results

A total of 193 patients were included (16.38 ± 4.89 years). Gingival growth occurred for 49.7% of patients included. The predisposing factors for this pathology during fixed orthodontic treatment were conventional metal brackets (p = 0.021), mouth breathing (p = 0.040), male gender (p = 0.035), thick periodontal phenotype (p = 0.043), elastomeric ligations (p = 0.007), duration of treatment (p = 0.022) and presence of plaque (p = 0.004). After achievement of the logistic regression, only two factors remained related to gingival enlargement: metallic brackets (OR: 3.5, 95% CI: 1.1–10.55) and duration of treatment (OR: 2.03, 95% CI: 1.01–4.08). The amount of plaque would not be directly related to the development of gingival increase during orthodontic treatment.

Conclusions

Among the predisposing factors that underlie gingival growth during multi-attachment therapy, the amount of plaque is not found. The qualitative assessment of the plaque and its evolution during treatment could clarify the role of the biofilm in the occurrence of gingival overgrowth.

The effect of the local administration of biological substances on the rate of orthodontic tooth movement: a systematic review of human studies

Background

The influence of different biological agents on the rate of orthodontic tooth movement (OTM) has been extensively reviewed in animal studies with conflicting results. These findings cannot be extrapolated from animals to humans. Therefore, we aimed to systematically investigate the most up-to-date available evidence of human studies regarding the effect of the administration of different biological substances on the rate of orthodontic tooth movement.

Methods

A total of 8 databases were searched until the 16th of June 2020 without restrictions. Controlled randomized and non-randomized human clinical studies assessing the effect of biological substances on the rate of OTM were included. ROBINS-I and the Cochrane Risk of Bias tools were used. Reporting of this review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Results

A total of 11 studies (6 randomized clinical trials and 5 prospective clinical trials) were identified for inclusion. Local injections of prostaglandin E1 and vitamin C exerted a positive influence on the rate of OTM; vitamin D showed variable effects. The use of platelet-rich plasma and its derivatives showed inconsistent results, while the local use of human relaxin hormone showed no significant effects on the rate of OTM.

Limitations

The limited and variable observation periods after the administration of the biological substances, the high and medium risk of bias assessment for some included studies, the variable concentrations of the assessed biological agents, the different experimental designs and teeth evaluated, and the variety of measurement tools have hampered the quantitative assessment of the results as originally planned.

Conclusions and implications

Despite the methodological limitations of the included studies, this systematic review provides an important overview of the effects of a variety of biological agents on the rate of tooth movement and elucidates the deficiencies in the clinical studies that have been conducted so far to evaluate the effectiveness of these agents in humans, providing some guidelines for future robust research.

Trial registration

PROSPERO (CRD42020168481, www.crd.york.ac.uk/prospero)

Assessment of cooperation and compliance in adult patients at three stages of orthodontic treatment at a tertiary care hospital: A cross-sectional study

OBJECTIVE

The study was conducted to assess cooperation and compliance in adult orthodontic patients during the leveling and alignment, space closure/molar correction and finishing stages of orthodontic treatment.

MATERIALS AND METHODS

This cross-sectional study was conducted on adult patients undergoing fixed orthodontic mechanotherapy in a tertiary care hospital. Patient cooperation was assessed during orthodontic treatment stages using Orthodontic Patient Cooperation Scale (OPCS) and compliance by Clinical Compliance Evaluation (CCE) form. A sample size of 38 subjects was included for each stage of treatment; therefore, a total of 114 subjects were recruited for the study. Shapiro-Wilk test identified that the data were normally distributed. One way ANOVA was used to evaluate the percentage cooperation and compliance among three stages. Pair-wise comparisons among the three stages were performed using Post hoc Tukey test. Simple and multiple linear regression analysis were carried out to see the factors associated with cooperation and compliance.

RESULTS

A statistically significant difference was seen for scores of patient cooperation and compliance using CCE (P=0.01); however, the results of the OPCS were non-significant among the three stages of treatment (P=0.16). There was a significant difference in patient cooperation and compliance between space closure/molar correction and finishing stage (P=0.01). A highly significant decline in oral hygiene was found with the progression of orthodontic treatment, from space closure/molar correction to the finishing stage of treatment (P<0.001).

CONCLUSIONS

Improvement in the cooperation and compliance levels for adult orthodontic patients was observed during the space closure/molar correction stage, which then showed a decline as the treatment progressed. Maintenance of oral hygiene was gradually reduced with the progression of orthodontic treatment.

Injectable RANKL sustained release formulations to accelerate orthodontic tooth movement

BACKGROUND

Accelerating orthodontic tooth movement (OTM) through biologically effective methods, such as increasing osteoclast-mediated alveolar resorption, could effectively shorten treatment time.

OBJECTIVE

To evaluate an injectable formulation containing receptor activator of nuclear factor kappa-B ligand (RANKL) on the OTM.

MATERIALS AND METHODS

We fabricated a RANKL formulation from 100 µl of 100 µg/ml RANKL adsorbed on 10 mg of poly(lactic acid-co-glycolic acid) microspheres embedded in a 10 wt% aqueous hydroxyethyl cellulose carrier gel. We characterized these formulations for the rate of RANKL release, and then tested for bioactivity using in vitro cell culture. In vivo OTM studies were conducted using 15 week old male Wistar rats for 14 days. We injected the RANKL formulations palatal to the left maxillary first molar and accomplished OTM with a nickel-titanium (NiTi) coil spring applying 5-8 g force. Control groups involved the application of NiTi coil spring with and without placebo formulation. The outcome measure included the distance of tooth movement, bone volume fraction, tissue density, and root volume determined with micro-computed tomography. We determined the amount of osteoclast activity using tartrate-resistant acid phosphatase (TRAP) staining.

RESULTS

These formulations were able to sustain the release of RANKL for more than 30 days, and the released RANKL showed a positive effect on mice osteoclast precursor cells (RAW 264.7). Reported injectable RANKL formulations were effective in accelerating OTM compared with other control groups, with 129.2 per cent more tooth movement than no formulation and 71.8 per cent more than placebo formulation, corresponding with a significant increase in the amount of TRAP activity. We did not observe any significant differences in root resorption between the groups.

CONCLUSION

Our study shows a significant increase in OTM with injectable formulations containing RANKL.

The effect of the extent of surgical insult on orthodontic tooth movement

OBJECTIVE

The primary objective of this study was to investigate how the extent of surgical insult affects the orthodontic tooth movement (OTM) and the alveolar bone modelling and remodelling in a rodent model.

MATERIAL AND METHODS

15-week-old male Wistar rats were used in the research and they were randomly divided into three treatment groups: (1) OTM only (N = 8); (2) OTM + 2 alveolar decortication (AD) (less surgical insult) (N = 8); and (3) OTM + 4 AD (more surgical insult) (N = 8). A nickel-titanium spring delivering 5-8 g of force was used to protract the molar mesially using maxillary incisors as an anchorage. AD was done using a hand piece and a round bur, adjacent to the left first maxillary molar on the palatal alveolar bone. After 14 days of OTM Wistar rats were killed and microfocus computed tomography and histological analysis were performed.

RESULTS

The OTM + 4AD group presented with a significant increase (P < 0.05) in the rate of tooth movement when compared to OTM + 2AD group and OTM only group. In addition, the OTM + 4AD group had a significant decrease in bone volume and tissue density (P < 0.05) and a significant increase (P < 0.05) in the trabecular spacing and trabecular thickness when compared to OTM only. Histological quantification of tartrate-resistant acid phosphatase indicated a significant percent increase (P < 0.05) in OTM + 4AD group, when compared to OTM + 2AD and OTM only group.

RESULTS

Increased surgical insult increases the rate of OTM. Additionally, increased surgical insult decreases the bone volume and the tissue density.

[Therapeutic effect analysis of skeletal class Ⅲ malocclusion treatment by transmission straight wire technique]

OBJECTIVE

This study aimed to investigate the therapeutic effects and advantages of skeletal class Ⅲ malocclusion treatment by transmission straight wire technique.

METHODS

Ninety-seven patients who received treatment for skeletal class Ⅲ malocclusion at the Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 2012 to January 2017 were selected for this retrospective study. All these patients refused surgery. They were divided into two groups in accordance with the type of skeletal malocclusion: mild-to-moderate skeletal malocclusion group (-4°≤ANB <0°) and severe skeletal malocclusion group (-8°≤ANB<-4°). Each of the two groups was divided further into two small groups in accordance with the technique used: T group (transmission straight wire technique) and M group (MBT technique).

RESULTS

The crossbite of all 59 patients in the mild-to-moderate skeletal malocclusion group was successfully treated. The molars were classified as classⅠrelationship, and the facial profile improved. Significant differences were found in the values of U1/SN angle, L1/MP angle, and Lip-Diff between the T and M groups before and after the treatment (P<0.05). The extent of incisor root resorption was lighter in the T group than in the M group (P<0.05). In the severe skeletal malocclusion group, the crossbite of all 38 patients was cured or partially cured. Fourteen patients showed severe lower anterior teeth inclination (five in the T group and nine in the M group), and the profiles did not significantly improve. Significant differences were observed in the values of U1-NA value, U1/SN angle, L1-NB value, L1/MP angle, LLP, and Lip-Diff between the T and M groups before and after the treatment (P<0.05). The extent of incisor root resorption was lighter in the T group than in the M group (P<0.05).

CONCLUSIONS

Relative to the MBT technique, the transmission straight wire technique has great advantages in improving facial profile, reducing the compensatory inclination of the upper and lower anterior teeth, and reducing the risk of root resorption in the treatment of skeletal class Ⅲ malocclusion.

Effects of micro-osteoperforations on intraoral miniscrew anchored maxillary molar distalization : A randomized clinical trial

PURPOSE

The aim was to study the effects of micro-osteoperforations (MOPs) on miniscrew-supported maxillary molar distalization.

METHODS

As part of a single center, split-mouth, randomized clinical trial, 20 eligible subjects were randomly recruited from patients who had applied to the orthodontics department of a university dental hospital. In the experimental group, subjects were randomized to receive MOPs to either the left or right maxillary molar region (n = 10). The control group (n = 10) and the contralateral sides of the experimental group (n = 10) did not receive any MOPs. In both groups, distalization of the maxillary molars was performed by miniscrew-supported distalization appliances. Using 3D models, maxillary molar distalization at 3, 6, 9, and 12 weeks was measured. Pain, discomfort, eating difficulty, and speech problem levels were assessed using a visual analog scale (VAS 0-10). Periodontal evaluations were performed.

RESULTS

In all, 18 subjects completed the study. The mean amount of tooth movement was significantly greater on the MOP side compared to contralateral side of the experimental group at all time points. After 12 weeks, the maxillary molars on the MOP side moved 1.17-fold more than those on the contralateral side. No significant differences were found regarding amount of tooth movement between the control group and the MOP and contralateral sides of the experimental group. The rates of tooth movement in the MOP sides of the experimental group, contralateral sides of the experimental group, and the control group were 0.029, 0.025, and 0.028 mm/day, respectively. Pain VAS scores after intervention were significantly increased on the MOP side compared with the contralateral side of the experimental group but not at any other time point. No differences in periodontal scores between the groups were observed.

CONCLUSIONS

A 1.17-fold increase in the rate of tooth movement in the MOP group compared with the contralateral side was recorded. However the accelerating effect of MOPs was lower than expected. The mean pain level was statistically greater in the MOP group compared to the contralateral side only on the first day of application.

Vestibular and lingual orthodontics: experimental study on plaque and blood indexes

BACKGROUND

In patients with fixed orthodontic treatment, good oral hygiene management is important to prevent complications such as caries, enamel demineralization, white spots, gingivitis, gingival hyperplasia and periodontitis. The aim of this experimental study is to compare the plaque and gingival indexes in patients with labial or lingual appliances.

METHODS

Twenty patients with a mean age of 27±-4.95 years were selected; ten patients (eight females and two males) between 17 and 39 years were fitted with a labial appliance while ten patients (nine females and one male) between 16 e 36 years were fitted with a lingual appliance. The dental hygienist made an evaluation using the plaque index and the gingival index, motivated and instructed the patients with labial and lingual devices to perform correct home oral hygiene. The timepoint were the following: T0 before the bonding, T1 one month after the bonding, T2 three months after the bonding, T3 six months after the bonding.

RESULTS

In the vestibular appliance at T0, the plaque index is significantly lower than the lingual device, but the bleeding index is significantly higher. Moreover, in both treatments, an increase in the parameters from T0 to T1, T2 and T3 was confirmed, and in the latter a linear increase trend both in the plaque index and in the gingival index can be observed.

CONCLUSIONS

The plaque and bleeding index increase gradually from T0 to T3, but there is no significant difference between the vestibular and lingual appliances.

Comparison of effects of bracket types and treatment duration on periodontal health of adult patients

Objective

The aim of this study was to assess the effect of fixed orthodontic treatments with steel-ligated conventional brackets and self-ligating brackets (SLBs) on periodontal clinical parameters.

Materials and Methods

Seventy-seven patients (24 male and 53 female) aged between 18 and 30 years were enrolled in the study. Periodontal parameters including plaque index (PI), gingival index (GI), and bleeding on probing (BOP) index were obtained from all the bonded teeth.

Results

When the effect of bracket type and duration of treatment on gingival tissues was examined, there was no statistically significant difference between the treatment times (P = 0.670) and bracket types (P = 0.596) in terms of PI. The GI was significantly different between the different treatment durations (P = 0.045); it was higher in patients with a treatment duration of 18–36 months. However, the GI did not change according to the bracket types (P = 0.270). This result was not significantly different between different treatment durations (P = 0.270). There was no significant difference between the treatment periods (P = 0.189) in terms of BOP index, and this result did not change according to the bracket types (P = 0.621).

Conclusion

SLBs do not require ligatures, which may facilitate plaque accumulation. However, our results showed that SLBs were not advantageous over CBs in terms of periodontal health.

Effect of micro-osteoperforation on the rate of orthodontic tooth movement—a systematic review and a meta-analysis

Background

The micro-osteoperforation can be used to increase the rate of tooth movement, simplify complex orthodontic movements, and also help adjust the anchorage but there are conflicting reports on the effectiveness and adverse effects of this intervention.

Objectives

The aim of our systematic review and meta-analysis was to evaluate the effects of micro-osteoperforation on the rate of tooth movement in patients undergoing orthodontic treatment.

Search methods

A comprehensive search of MEDLINE, ISI web of science, EMBASE, Scopus, and CENTRAL online databases for studies measuring the effects of micro-osteoperforation on the rate of orthodontic tooth movement from inception to February 2019 was performed.

Selection criteria

Based on the PICO model, human studies which evaluated the effects of MOP on the rate of tooth movement in patients undergoing orthodontic treatment were selected for this review.

Data collection and analysis

The relevant data from the eligible studies were extracted using piloted custom extraction forms. The data were combined and analysed using inverse-variance random-effect meta-analysis and the mean difference was used for comparing the outcome measures.

Results

Six randomized clinical trials were finally included in this meta-analysis. The rate of canine retraction per month was significantly higher in the MOP group [mean difference (MD) = 0.45 mm, 95% CI = 0.17–0.74]. These results were similar with regard to different malocclusions, the jaw on which it was performed, and MOP methods. The patients did not report any significant differences in terms of pain severity levels after MOP. With regard to the adverse effects, one study reported higher amounts of root resorption among patients undergoing MOP.

Conclusions

The rate of tooth movement was increased after performing MOP but in at least one study higher root resorption was observed. Therefore, the use of MOP can be recommended after weighing the benefits and disadvantages this intervention can bring for each patient.

Registration

The protocol for this review was registered via crd.york.ac.uk/prospero with the ID CRD42019115499.

Tissue response resulting from different force magnitudes combined with corticotomy in rats

OBJECTIVES

To evaluate the amount of hyalinization and root resorption after application of light and heavy forces during corticotomy-assisted tooth movement.

MATERIALS AND METHODS

Forty-eight male Wistar rats were used. Eight animals were the control group (day 0). The other 40 animals were randomly divided into two groups using the split-mouth technique: (1) corticotomy combined light force (CLF) and (2) corticotomy combined heavy force (CHF). Nickel-titanium closed coil springs that generated 10 g (light force) and 50 g (heavy force) were used for maxillary first molar movement. three-dimensional root volume was evaluated at 0, 14, and 28 days. Percent hyalinization was analyzed at 0, 3, 7, 14, 21, and 28 days by histomorphometric analysis.

RESULTS

The CHF group showed significantly lower cervical root volume than the CLF group at 28 days. Compared with day 0, the CHF group showed significantly less root volume in both distobuccal and distopalatal roots at 28 days. The hyalinization percentages in the CHF group were significantly higher than the CLF group at days 3 and 21.

CONCLUSIONS

Heavy force combined with corticotomy produced more periodontal ligament hyalinization and root resorption than the light force combined with corticotomy.

Subgingival Microbial Changes During the First 3 Months of Fixed Appliance Treatment in Female Adult Patients

Although periodontal diseases during fixed appliance treatment are a common issue, few studies have focused on the clinical and microbial factors associated with orthodontic appliances. Hence, we investigated changes in the subgingival microbial community and their association with periodontal changes at the early stage of fixed appliance treatment. Subgingival plaques from ten female patients with fixed appliances were obtained at three time points: before, 1 month and 3 months after the placement of the brackets (T0, T1 and T2). The 16S rRNA gene sequencing was used to analyze the microbial community of the subgingival plaque. The Plaque Index (PI) and Gingival Bleeding Index (GBI) were also recorded. The GBI significantly increased at T2, and the PI showed a temporary increase without a significant difference. The alpha diversity indices were stable. However, the beta diversity was significantly higher at T2 compared to T0 and T1. The relative abundance of core microbiomes at the genus level was relatively stable. Four periodontal pathogens at the species level, including Prevotella intermedia (Pi), Campylobacer rectus (Cr), Fusobacterium nucleatum (Fn), and Treponema denticola (Td), increased without significant differences. The subgingival microbial community affected by fixed appliance treatment might cause transient mild gingival inflammation.

Does the Duration of Fixed Orthodontic Treatment Affect Caries Activity among Adolescents and Young Adults?

This cross-sectional study assessed the relationship between fixed orthodontic treatment duration and caries activity. Two hundred and sixty 10- to 30-year-olds were divided into 4 groups (n = 65): no fixed orthodontic appliances (G0), orthodontic treatment for 1 year (G1), 2 years (G2), or 3 years (G3). Orthodontic treatment duration was significantly associated with active caries: prevalence was 1.5% for G0, 27.7% for G1, and 72.3% for G2 and G3; the median number of lesions was 0 for G0 and G1 and 2 for G2 and G3. No differences were observed between G2 and G3. The longer the duration of orthodontic treatment, the higher the prevalence/extent of active caries lesions.