Three-dimensional evaluation of secondary alveolar bone grafting in patients with unilateral cleft lip and palate: A 2-3 year post-operative follow-up.

OBJECTIVES: The present study aims to quantitatively assess secondary alveolar bone graft (SABG) resorption in unilateral cleft lip, alveolus and palate (UCLAP) patients in a 2-3 year longitudinal follow-up setting by using a validated 3D protocol. Furthermore, the potential relation of SABG resorption with maxillary canine position and a number of patient-related factors was investigated. METHODS: UCLAP patients who underwent SABG and had good quality CBCT images at the following timepoints were included in the study: pre-operative (T0), immediate (T1), 6 months (T2) and either 1-2 years (T3) or 2-3 years (T4) post-operative. The final bone grafted region was defined on the T1 scans and refined in the registered T0 scans. The bone graft after resorption was determined by applying threshold-based segmentation on the registered T2, T3 or T4 scans within the segmented bone graft volume. The position of the canines was determined at every timepoint at the cleft and non-cleft side. RESULTS: Forty-five UCLAP patients (mean age 9.0 ± 1.3 years) were included. In the first 6 months after SABG, 43.6% bone resorption was recorded. 2-3 years post-operative, 56% bone resorption was found if the maxillary canine was not yet erupted and 42.7% if it erupted through the graft. The vertical position of the canines was significantly higher on the cleft side at T3. CONCLUSIONS: The present study reports significant SABG resorption over time. However, no correlation was found between SABG resorption and canine position, nor between other patient-related factors.

Initial development of an 'Orthodontic Care Index' involving treatment need,-complexity and-priority.

BACKGROUND/OBJECTIVES: The aim of this study was to develop an evidence-based scoring system for prioritizing limited orthodontic resources based on orthodontic treatment need (OTN), orthodontic treatment complexity (OTC), and orthodontic treatment priority (OTP), which is not merely a scoring system for malocclusion but also a comprehensive classification of orthodontic issues incorporating patient- and treatment-related factors, called Orthodontic Care Index (OCI). MATERIALS AND METHODS: The development of the OCI involved eight phases, starting with a systematic literature review to identify all possible parameters involved in determining OTN, OTC, and OTP. An eight-member orthodontic specialist panel then evaluated and scored the significance of each parameter, resulting in a parameter-score list. Subsequently, a retrospective convenience sample of 61 patients was scored with the parameter-score list, and using the same convenience sample a gold standard was established through the expert opinion of a third orthodontic panel. Linear regression analysis was used to estimate weights of importance and construct a formula to calculate index scores. Lastly, the expert opinion was compared to the index scores, to determine the index performance. RESULTS: The preliminary index separately calculates OTN, OTC, and OTP for a patient as the weighted sum of his/her domain scores. The sensitivity of the index for predicting OTN, OTC, and OTP was high (98.1%, 82.9%, and 92.7% respectively), while the variability of each was relatively low (52.1%, 31.2%, and 52.6% respectively). CONCLUSIONS/IMPLICATIONS: The OCI shows promise as a guideline for prioritizing orthodontic care. It will be further refined and validated to enhance its performance and usefulness.

Are palatal rugae reliable markers for 3D superimposition and forensic human identification after palatal expansion? A systematic review.

OBJECTIVES: Palatal rugae are periodic structures situated in the palatal mucosa, often used as landmarks for human identification and superimposition of digital dental models. This review aims to collect the current evidence regarding whether orthodontic palatal expansion could affect the stability of the palatal rugae and to give preliminary guidelines. MATERIALS AND METHODS: A systematic review of the literature was performed in the scientific databases Pubmed; Embase; WoS; and Cochrane. Grey Literature was also sought (clinicaltrial.gov; ICTRP; AHRQ; INAHTA). The search protocol, was registered in PROSPERO (N*208722). Data extraction comprised: year of publication, journal, sample size, characteristics of the experimental and control group, type of expander, expansion protocol, rugae classification, measurement method on casts, time between casts, method error, rugae change, morphology change and overall outcome. Risk of bias of the included articles was evaluated with the Newcastle-Ottawa Scale. RESULTS: A total of 12394 manuscripts were retrieved after duplicate removal. From these, nine articles were finally included for data extraction. three studies scored as low risk of bias, two as medium and four as high. CONCLUSIONS: The morphology of the palatal rugae can be modified by palatal expansion techniques, especially by rapid maxillary expansion. The first rugae is the most stable along with the points close to the palatal midline, which should be used as a reference both for manual or semi-automatic superimpositions. Human identification and serial superimpositions based on palatal rugae should not be carried immediately post expansion and be taken in consideration with caution in patients who underwent prior palatal expansion.

Risk factors for orthodontic fixed retention failure: A retrospective controlled study.

Objective: : To investigate the potential correlation between fixed orthodontic retention failure and several patient- and treatment-related factors. Methods: : Patients finishing treatment with fixed appliances between 2016 and 2017 were retrospectively included in this study. Those not showing fixed retention failure were considered as control group. Patients with fixed retention failure were considered as the experimental group. Additionally, patients with failure of fixed retainers in the period of June 2019 to March 2021 were prospectively identified and included in the experimental group. The location of the first retention failure, sex, pretreatment dental occlusion, facial characteristics, posttreatment dental occlusion, treatment approach and presence of oral habits were compared between groups before and after treatment separately by using a Fisher exact test and a Mann-Whitney U test. Results: : 206 patients with fixed retention failure were included, 169 in the mandibular and 74 in the maxillary jaws. Significant correlations were observed between retention failure in the mandibular jaws and mandibular arch length discrepancy (P = 0.010), post-treatment growth pattern (P = 0.041), nail biting (P < 0.001) and abnormal tongue function (P = 0.002). Retention failure in the maxillary jaws was more frequent in patients with IPR in the mandibular jaws (P = 0.005) and abnormal tongue function (P = 0.021). Conclusions: : This study suggests a correlation between fixed retention failure and parafunctional habits, such as nail biting and abnormal tongue function. Prospective studies with larger study populations could further confirm these results.

Relation between Maximum Oral Muscle Pressure and Dentoalveolar Characteristics in Patients with Cleft Lip and/or Palate: A Prospective Comparative Study.

BACKGROUND: Perioral muscle function, which influences maxillofacial growth and tooth position, can be affected in patients with oral clefts due to their inherent anatomical characteristics and the multiple surgical corrections performed. This research aims to (1) compare the maximum oral muscle pressure of subjects with and without isolated cleft palate (CP) or unilateral cleft lip and palate (UCLP), (2) investigate its influence on their dentoalveolar characteristics, and (3) investigate the influence of functional habits on the maximum oral muscle pressure in patients with and without cleft. MATERIAL AND METHODS: Subjects with and without CP and UCLP seeking treatment at the Department of Orthodontics of University Hospitals Leuven between January 2021 and August 2022 were invited to participate. The Iowa Oral Performance Instrument (IOPI) was used to measure their maximum tongue, lip, and cheek pressure. An imbalance score was calculated to express the relationship between tongue and lip pressure. Upper and lower intercanine (ICD) and intermolar distance (IMD) were measured on 3D digital dental casts, and the presence of functional habits was reported by the patients. The data were analyzed with multivariable linear models, correcting for age and gender. RESULTS: 44 subjects with CP or UCLP (mean age: 12.00 years) and 104 non-affected patients (mean age: 11.13 years) were included. No significant differences in maximum oral muscle pressure or imbalance score were detected between controls and clefts or between cleft types. Significantly smaller upper ICDs and larger upper and lower IMDs were found in patients with clefts. A significant difference between controls and clefts was found in the relationship between oral muscle pressure and transversal jaw width. In cleft patients, the higher the maximum tongue pressure, the wider the upper and lower IMD, the higher the lip pressure, the smaller the upper and lower ICD and IMD, and the higher the imbalance score, the larger the upper and lower IMD and lower ICD. An imbalance favoring the tongue was found in cleft patients. The influence of functional habits on the maximum oral muscle pressure was not statistically different between clefts and controls. CONCLUSION: Patients with CP or UCLP did not present reduced maximum oral muscle pressure compared with patients without a cleft. In cleft patients, tongue pressure was consistently greater than lip pressure, and those who presented a larger maxillary width presented systematically higher imbalance scores (favoring the tongue) than those with narrow maxillae. Therefore, the influence of slow maxillary expansion on maximum oral muscle pressure in cleft patients should not be underestimated.

Performance of the Malmgren Index for Assessing Root Resorption on 2D vs. 3D Radiographs: A Pilot Study.

OBJECTIVES: To compare the performance of the Malmgren index on 2D and 3D radiographs. METHODS: Patients with a panoramic radiograph and a cone beam computed tomography (CBCT) taken at an interval of <3 months and presenting root resorption (RR) on at least one incisor and/or canine were retrospectively included. RR was scored twice by two observers using the Malmgren index in both the 2D and 3D sets, and intra-class correlation coefficient (ICC) was calculated. RESULTS: 155 teeth were analyzed. The ICC was the lowest in 2D, followed by overall, transversal and sagittal 3D. Malmgren scores were systematically higher in 2D, which overestimated RR, especially in the transversal plane on all incisors and canines and in the sagittal plane on the maxillary incisors. 2D respectively leads to 28.0-34.8% of false positives and negatives when discriminating between RR or not. The early stages of RR are often misdiagnosed in 2D, while later stages are more accurate. CONCLUSIONS: The original Malmgren index is not suited for 3D images, especially axial, where using dichotomized values (resorption yes/no) leads to overestimation of RR. A low-dose CBCT of the upper incisors could detect RR with high diagnostic accuracy in the early stages of orthodontic treatment, especially in patients with dental trauma or familial RR history.

Risk factors for gingival recessions after orthodontic treatment: a systematic review.

BACKGROUND/OBJECTIVES: To systematically review the available evidence concerning the risk factors for gingival recessions (GR) after orthodontic treatment (OT). DATA COLLECTION AND ANALYSIS: Data was obtained and collected by systematically searching 3 data bases: Pubmed, EMBASE, and Web of Science until 20 April 2023. Controlled trials, cohort, case-control or cross-sectional studies describing GR or clinical crown height (CCH) after OT were included. The risk of bias in the selected studies was evaluated with the methodological index for non-randomized studies. RESULTS: Forty-eight articles were included, investigating the following six risk factors for GR: 1. OT (n = 21), 2. Type of orthodontic intervention (n = 32), 3. Patient's baseline occlusal and skeletal characteristics (n = 14), 4. Mucogingival characteristics (n = 10), 5. Oral hygiene (n = 9), and 6. Others (n = 12). Significantly higher prevalence, severity and extent of GR were found in orthodontic patients by 10/15, 4/10, and 2/2 articles respectively. 10/16 articles reported significantly more GR and increased CCH in patients where orthodontic incisor proclination was performed. The evidence surrounding maxillary expansion and orthodontic retention was too heterogeneous to allow for? definitive conclusions. Pre-treatment angle classification, ANB, overjet, overbite, arch width and mandibular divergence were found not to be associated with GR (9/14), while pre-treatment crossbite, symphysis height and width were (5/7 studies). A thin gingival biotype, presence of previous GR, baseline width of keratinized gingiva and facial gingival margin thickness were correlated with increased risk of GR after OT by nine articles, while pocket depth was not. Oral hygiene, sex, treatment duration, and oral piercings were found not to be linked with GR in orthodontic patients, while GR was reported to increase with age in orthodontic patients by 50 per cent of the articles investigating this factor. The mean risk of bias for comparative and not comparative studies was 14.17/24 and 9.12/16. LIMITATIONS: The selected studies were quite heterogeneous regarding study settings, variables reported and included very limited sample sizes. CONCLUSION: Although studies regarding the risk factors for GR are relatively abundant, they are very heterogeneous concerning design, studied factors, methodology and reporting, which often leads to contradictory results. Uniform reporting guidelines are urgently needed for future research. PROSPERO REGISTRATION: CRD42020181661. FUNDING: This research received no funding.

Early prevention of maxillary canine impaction: a randomized clinical trial.

OBJECTIVES: To investigate the effect of three interceptive measures (slow maxillary expansion (SME) with removable plates (1), extraction of both upper deciduous canines (DC) (2) and no intervention (3)) on maxillary canine (MC) position in patients with early mixed dentition (EMD) and lack of upper arch space. These three groups were additionally compared to a control group (4) with adequate upper arch space. NULL HYPOTHESIS: None of the studied strategies outperforms the others regarding improvement of MC position. TRIAL DESIGN: Four-arm parallel group prospective randomized controlled trial. PARTICIPANTS: Patients in EMD with at least one impacted MC, non-resorbed DC, and no crossbite. INTERVENTIONS: Patients with a lack of space were randomly distributed to protocols (1), (2), and (3). PRIMARY OBJECTIVE: To assess the change in MC position after 18 months follow up. SECONDARY OBJECTIVES: To assess canine eruption and need for orthodontic intervention within 18-60 month follow up. OUTCOME ASSESSMENT: Five variables defined canine position: sector, canine-to-midline angle, canine-to-first-premolar angle, canine-cusp-to-midline distance, and canine-cusp-to-occlusal-plane distance on two panoramic radiographs at 0 (T1) and 18 months (T2). Mean differences between groups were compared with linear mixed models, corrected for age and sex. RANDOMIZATION: The patient allocation sequence was generated by an electronic randomization list. BLINDING: The operator taking the measurements was blinded to the groups. RESULTS: Seventy-six patients were included (142 canines, mean age 9.2 years, 60.5 per cent male, mean follow up 1.9 years), 19, 17, 14, and 26 patients in groups 1-4, respectively. In absence of dental crossbite in patients with lack of space and impacted MC, SME improved the canine sector (P = 0.040), compared to no intervention (P = 0.028). Canine-to-midline angle and canine-to-occlusal-plane distance significantly decreased in all groups at T2. Extraction improved the canine-to-first-premolar angle at T2 more than other strategies in EMD (P = 0.015-0.000). CONCLUSIONS: Early SME improves the canine sector and reduces the need for major orthodontic intervention in the long term. Taking a first panoramic radiograph in EMD allows timely intervention in case of MC impaction. TRIAL REGISTRATION NUMBER: NCT05629312 (Clinical Trials.org). Trial status: follow up ongoing.

Nanomaterials for Periodontal Tissue Regeneration: Progress, Challenges and Future Perspectives.

Bioactive nanomaterials are increasingly being applied in oral health research. Specifically, they have shown great potential for periodontal tissue regeneration and have substantially improved oral health in translational and clinical applications. However, their limitations and side effects still need to be explored and elucidated. This article aims to review the recent advancements in nanomaterials applied for periodontal tissue regeneration and to discuss future research directions in this field, especially focusing on research using nanomaterials to improve oral health. The biomimetic and physiochemical properties of nanomaterials such as metals and polymer composites are described in detail, including their effects on the regeneration of alveolar bone, periodontal ligament, cementum and gingiva. Finally, the biomedical safety issues of their application as regenerative materials are updated, with a discussion about their complications and future perspectives. Although the applications of bioactive nanomaterials in the oral cavity are still at an initial stage, and pose numerous challenges, recent research suggests that they are a promising alternative in periodontal tissue regeneration.

Third molar position after completion of orthodontic treatment: a prospective follow-up.

OBJECTIVES: To prospectively follow up a previously reported sample, analyzing (1) changes in third molar (M3) position after completion of 2 different types of orthodontic treatment: (2) non-extraction treatment with (HG) vs without cervical headgear (non-HG) and (3) first or second premolar extractions (PM1-2) compared to a non-extraction group (NE). METHODS: A total of 474 patients were prospectively followed up. Panoramic radiographs were taken pre- (T1), post-treatment (T2) and at follow-up (T3). T3 records (a mean of three years after treatment) were available for 135 (HG vs non-HG) and 134 patients (PM1-2 vs NE), respectively. Angulation, vertical position, relation with the mandibular canal and mineralization status of M3 at T2 and T3 were statistically compared. RESULTS: The HG group presented more M3 with ideal vertical orientation at T3. In NE-cases, further improvement in angulation and orientation can be expected after debonding, as well as a deterioration in the relationship with the mandibular canal. Extractions accelerated upper M3 vertical eruption and PM2 extractions led to long-term larger lower retromolar spaces. CONCLUSIONS: The use of cervical headgear increased upper M3 uprighting three years after debonding, while little changes in M3 position were found after orthodontic treatment with extractions. However, PM2 extractions led to larger retromolar spaces and better M3 angulation in the long term.

Biomimetic Periodontal Ligament Transplantation Activated by Gold Nanoparticles Protects Alveolar Bone.

Stem cell therapy might be a promising method to stimulate alveolar bone regeneration, which is currently a major clinical challenge. However, its therapeutic features largely depend on pretreatment and transplantation preparation. Herein, a novel biomimetic periodontal ligament transplantation composed of human periodontal ligament stem cells (hPDLSCs) pretreated with gold nanocomplexes (AuNCs) and embedded in a type-I collagen hydrogel scaffold is developed to protect alveolar bone from resorption. AuNCs are readily absorbed by primary hPDLSCs, with limited cytotoxicity, and promote osteogenic differentiation of hPDLSCs effectively in vitro. In addition, the AuNCs-induced hPDLSCs are encapsulated with type-I collagen hydrogel scaffold to mimic their native physiological niche, and then are transplanted into a rat model of alveolar bone resorption. Both micro-computed tomography (micro-CT) and immunohistochemical assays demonstrate that alveolar bone loss is significantly prevented. Furthermore, the underlying therapeutic mechanism is elucidated, in which transplantation-activated osteogenesis is associated with autophagy, which enables bone remodeling and regeneration. This study provides critical insight into the role of PDLSCs in bone homeostasis and proposes an innovative AuNCs-based strategy for stem cell therapy in bone regeneration.

Long-term effects of orthodontic interceptive expansion treatment : A retrospective study.

PURPOSE: The aim of this retrospective cohort study was to evaluate the long-term effects of interceptive orthodontic treatment with a removable expansion plate, based on transversal, sagittal, and vertical parameters. METHODS: A total of 90 patients needing interceptive treatment due to a crossbite or space deficiency were included. Records consisting of clinical photos, radiographs, and digital dental casts were collected for evaluation at two time points: the start of interceptive treatment (T0) and the start of comprehensive treatment (T1). Molar occlusion, overjet, overbite, presence and type of crossbite, mandibular shift, and transversal measurements were recorded for comparison. RESULTS: After expansion with removable appliances, a significant increase in intermolar width was achieved and could be maintained over the observation period (p < 0.001). However, no significant changes regarding overjet, overbite, or molar sagittal occlusion were observed. Crossbite correction was successful in 86.9% of patients with unilateral crossbite and in 75.0% of patients with bilateral crossbite (p < 0.001). CONCLUSION: Early expansion with a removable expansion plate is a successful method to correct crossbites and increase intermolar width in the early mixed dentition phase. Results remain stable until the start of comprehensive treatment in the permanent dentition.

Comparison of human dental tissue RNA extraction methods for RNA sequencing.

OBJECTIVE: The purpose of this study was to identify an efficient RNA extraction method for periodontal ligament (PDL) and dental pulp (DP) tissues to be used in RNA sequencing studies, given the increased use of these techniques in dental research and the lack of standard protocols. DESIGN: PDL and DP were harvested from extracted third molars. Total RNA was extracted with four RNA extraction kits. RNA concentration, purity and integrity were assessed by means of NanoDrop and Bioanalyzer and statistically compared. RESULTS: RNA from PDL was more likely to be degraded than that of DP. The TRIzol method yielded the highest RNA concentration from both tissues. All methods harvested RNA with A260/A280 close to 2.0 and with A260/A230 above 1.5, except for the A260/A230 from PDL obtained with the RNeasy Mini kit. For RNA integrity, the RNeasy Fibrous Tissue Mini kit yielded the highest RIN values and 28 S/18 S from PDL, while the RNeasy Mini kit obtained relatively high RIN values with an appropriate 28 S/18 S for DP. CONCLUSION: Significantly different results were obtained for PDL and DP when using the RNeasy Mini kit. The RNeasy Mini kit provided the highest RNA yields and quality for DP, while the RNeasy Fibrous Tissue Mini kit obtained the highest quality RNA from PDL.

The use of blended learning in postgraduate education in orthodontics: student versus teacher perception.

OBJECTIVE: To investigate the use of blended learning (BL) in Postgraduate Education in Orthodontics. METHODS: A self-developed online questionnaire was sent to 244 teaching staff members of the European Orthodontic Departments. They were asked to answer it and share it with their postgraduate students. 18 questions for teaching staff and 27 for postgraduate students evaluated the use, perceptions, feedback options, learning outcomes, and teacher's role in BL. The answers of teaching staff and students were statistically compared by Fisher's Exact Test, Chi-Square Test, Unpaired t-test, and Mann-Whitney Test. RESULTS: 124 completed questionnaires were received, 44 from teaching staff and 80 from postgraduate students. Teaching staff is more acquainted with BL than students (P = 0.001). Both groups found BL courses a good alternative to traditional courses (P = 0.654). The use of interactive multimedia was more appreciated by students (P = 0.015). Both groups found students' results not to change with BL, but teaching staff had a more negative perception (P = 0.012). In general, teaching staff perceived feedback and interaction as less essential than postgraduates in BL. Teaching staff felt more like coaches when using BL, while postgraduates did not perceive any changes in teachers' roles (P = 0.006). Limitations: Due to the General Data Protection Regulation it was not possible to directly contact the postgraduate students in Postgraduate Orthodontic Programs throughout Europe. Therefore, this study completely relied on the goodwill of the teaching staff being contacted. CONCLUSION: The main differences in perception between teaching staff and postgraduate students were student results, teachers' role, use, and importance of feedback and interactive multimedia. Although both groups found BL courses to stimulate students' learning and to be a relevant cost-effective addition to traditional courses, they were hesitant to fully replace them with BL.

Age- and sex-related differences in 3D facial shape and muscle pressure in subjects with normal occlusion.

BACKGROUND AND OBJECTIVE(S): (1) To derive descriptive statistics of three-dimensional (3D) facial shape, lip and cheek muscle pressure in subjects of European descent with normal dental occlusion. (2) To analyse the effect of age and sex on 3D-facial soft tissue morphology and muscle pressure in the same sample. (3) To assess the independent effect of muscle pressure on face shape. METHOD: 129 subjects with normal occlusion were cross-sectionally recruited and divided into: children (mixed dentition), adolescents and adults (permanent dentition, < and ≥18 years respectively). Muscle pressure was recorded using the Iowa Oral Performance Instrument. MeshLab, MeVisLab and Meshmonk tool box were used to clean, annotate landmarks and generate the 3D images. Two-way analysis of variance and post-hoc tests were used to analyse age and sex differences in face shape and muscle pressure. The effect of muscle pressure on face shape was analysed by Pearson correlation and Partial Least Square regression. RESULTS: Significant facial differences were observed between adults and adolescents and adults and children in both sexes, showing flattening of cheeks and lips and protrusion of nose and chin. Significant cheek protrusion and retrusion of the vertical midface were found in adult women compared to men. Lip and cheek pressure increased with age, but their effect on face shape was not significant. CONCLUSIONS: This study provides 3D age- and sex-specific facial models and muscle pressure of subjects without malocclusion. These can be used as a reference for clinicians focused on facial assessment in treatment planning and follow-up.

Dynamic changes in tooth displacement and bone morphometry induced by orthodontic force.

This study used a novel 3D analysis to longitudinally evaluate orthodontic tooth movement (OTM) and bone morphometry. Twelve-week-old male Wistar rats were subjected to OTM by applying a constant orthodontic force (OF) of 25cN between one of the upper first molars and a mini-screw. In vivo micro-CTs were taken before and after 10, 17, 24 and 31 days of force application, and superimposed by a novel and rigid voxel-based registration method. Then the tooth and alveolar bone segment at different time points became comparable in the same coordinate system, which facilitated the analysis of their dynamic changes in 3D. By comparison between time points and between OF and no OF sides, this study showed that the OTM rate was not constant through time, but conformed to a 'V' shape changing pattern. Besides, OF induced displacement of both loaded and unloaded teeth, and the latter mirrored the former in a delayed manner. In addition, bone morphometric changes synchronized with OTM rate changes, implying that a higher OTM rate was concomitant with more alveolar bone loss. The pressure and tension areas might not be in two opposite sides, but actually adjacent and connected. These findings might provide instructive evidence for both clinical, translational and basic research in orthodontics.

Evolution of root length throughout orthodontic treatment in maxillary incisors with previous history of dental trauma: a longitudinal controlled trial.

OBJECTIVES: To compare changes in root length of maxillary incisors with and without dental trauma throughout orthodontic treatment. MATERIALS AND METHOD: Patients younger than 18 years, with trauma on at least one maxillary incisor, undergoing orthodontic treatment between 2017 and 2021 were included, using the contralateral side as control without trauma when available. Periapical radiographs were taken pre-treatment and at 6 months intervals, and root/crown ratio was calculated. Linear mixed models were used to describe the evolution of root length at the different time points and to compare trauma and control values. Differences between central and lateral incisors and between treatment modalities were additionally explored. RESULTS: A total of 1768 measurements were performed on 499 teeth (201 with trauma) in 135 patients. Incisor root length significantly decreased during orthodontic treatment in teeth with and without trauma. Lateral incisors with trauma were more susceptible to root resorption than those without trauma and central incisors. No significant decrease in root length was observed with removable appliances, which never exceeded 15 months of treatment. Treatment with fixed appliances led to gradually increasing, significant root length shortening in teeth with and without trauma. CONCLUSION: Treatment duration directly correlated with root length shortening both in teeth with and without trauma history. Teeth with trauma showed significantly more root resorption after treatment with fixed appliances while removable appliances had no significant influence on root length. CLINICAL RELEVANCE: Previous history of dental trauma is no absolute contra-indication to start orthodontic treatment, as long as treatment duration is kept as short as possible.

Prevalence of Orthodontic Malocclusions in Healthy Children and Adolescents: A Systematic Review.

The purpose of this study was to systematically review the literature regarding the prevalence of malocclusion and different orthodontic features in children and adolescents. METHODS: The digital databases PubMed, Cochrane, Embase, Open Grey, and Web of Science were searched from inception to November 2021. Epidemiological studies, randomized controlled trials, clinical trials, and comparative studies involving subjects ≤ 18 years old and focusing on the prevalence of malocclusion and different orthodontic features were selected. Articles written in English, Dutch, French, German, Spanish, and Portuguese were included. Three authors independently assessed the eligibility, extracted the data from, and ascertained the quality of the studies. Since all of the included articles were non-randomized, the MINORS tool was used to score the risk of bias. RESULTS: The initial electronic database search identified a total of 6775 articles. After the removal of duplicates, 4646 articles were screened using the title and abstract. A total of 415 full-text articles were assessed, and 123 articles were finally included for qualitative analysis. The range of prevalence of Angle Class I, Class II, and Class III malocclusion was very large, with a mean prevalence of 51.9% (SD 20.7), 23.8% (SD 14.6), and 6.5% (SD 6.5), respectively. As for the prevalence of overjet, reversed overjet, overbite, and open bite, no means were calculated due to the large variation in the definitions, measurements, methodologies, and cut-off points among the studies. The prevalence of anterior crossbite, posterior crossbite, and crossbite with functional shift were 7.8% (SD 6.5), 9.0% (SD 7.34), and 12.2% (SD 7.8), respectively. The prevalence of hypodontia and hyperdontia were reported to be 6.8% (SD 4.2) and 1.8% (SD 1.3), respectively. For impacted teeth, ectopic eruption, and transposition, means of 4.9% (SD 3.7), 5.4% (SD 3.8), and 0.5% (SD 0.5) were found, respectively. CONCLUSIONS: There is an urgent need to clearly define orthodontic features and malocclusion traits as well as to reach consensus on the protocols used to quantify them. The large variety in methodological approaches found in the literature makes the data regarding prevalence of malocclusion unreliable.

3D quantification of in vivo orthodontic tooth movement in rats by means of micro-computed tomography.

OBJECTIVE: (1) To test the accuracy of split-mouth models in rats for the study of orthodontic tooth movement (OTM) and (2) to propose an improved 3D model for quantification of OTM in rats. METHODS: Eleven Wistar rats were split into group 1 (dental anchorage) and group 2 (skeletal anchorage). In both groups, no orthodontic force (OF) was applied on the contralateral hemi-maxilla. In vivo micro-CT images were taken before (T0) and 31 days (T1) after OF. OTM was compared between time-points and experimental sides using conventional 2D analysis and a novel 3D model. RESULTS: Using incisors as anchorage leads to their distal displacement in both OF and no OF sides. In the OF side, movement of M1 is underestimated by incisor displacement. Mesial displacement of M1 was found in the no OF side of all groups 31 days after the application of OF. CONCLUSIONS: The new 3D model yielded higher sensitivity for tooth displacement in planes other than sagittal and incisor displacement was reduced by using skeletal anchorage. CLINICAL SIGNIFICANCE: Studies following split-mouth designs in orthodontic research in rats might be systematically underestimating the effects of techniques and/or medication on OTM, since there is tooth displacement on the control side. 3D quantification of OTM with skeletal anchorage is more sensitive and avoids displacement of the dental units used as anchorage.

Determination of craniofacial and dental characteristics of individuals with Williams-Beuren syndrome by using 3D facial scans and radiographs.

BACKGROUND: Williams-Beuren syndrome (WBS) is caused by a microdeletion on chromosome 7q11-23 and clusters a variety of systemic affectations. AIM: To investigate whether 3D facial scans can detect WBS by objectively addressing their craniofacial, skeletal and dental characteristics, compared with those of a non-affected control group. MATERIALS AND METHODS: 3D facial surface scans of 17 WBS individuals and 33 normal developing patients were analysed. Additionally, cephalometric and panoramic radiographs of subjects with WBS were compared with those of non-affected individuals. RESULTS: The 3D surface scans showed significant facial differences around the nose and mouth area. The cephalometric aspects of individuals with WBS differed mainly at the lower incisor region. Additionally, hypoplastic tooth morphology seems to be more often present in WBS. CONCLUSION: 3D images are a non-invasive, efficient method to observe facial anomalies and facilitate an early diagnosis of WBS. Additionally, the analysis of the cephalometric and panoramic images revealed significant differences in dental characteristics. Together with early diagnosis through 3D images, these can help in the establishment of adequate medical, dental and orthodontic treatment planning.