STATEMENT OF PROBLEM:The accuracy of virtual interocclusal records is critical in fully digital prosthodontic workflows. Although manufacturers provide recommended scanning protocols, clinicians may deviate from them in daily practice. The impact of such deviations on virtual articulation accuracy across intraoral scanners remains unclear. PURPOSE:The purpose of this in vitro study was to evaluate and compare the accuracy of virtual interocclusal records obtained using 4 intraoral scanners under manufacturer-recommended and alternative scanning protocols. MATERIAL AND METHODS:A typodont cast was duplicated in Type III dental stone, mounted in maximum intercuspal position (MIP) on a semi-adjustable articulator, and scanned. Four intraoral scanners-TRIOS3 (TS), Primescan (PS), Smile Scan (SM), and CS3800 (CS)-were used to obtain interocclusal records (n=10 per scanner per protocol) using manufacturer-recommended protocols and alternative protocols deviating from manufacturer instructions (complete arch or bilateral interocclusal registration scans). The standard tessellation language (STL) files were analyzed in Geomagic Control X, aligned to a reference cast, and trueness and precision were assessed at 3 standardized locations. Mixed-design ANOVA models were applied to RMS bias (trueness), with position (left, center, right) as a within-subject factor and scanner type as a between-subject factor; protocol was included as an additional between-subject factor, with a separate model for CS3800. Post hoc pairwise comparisons were performed using the Tukey adjustment (α=.05). RESULTS:Under manufacturer-recommended protocols, no significant differences in trueness were observed among TS (0.215 mm), PS (0.242 mm), and SM (0.222 mm) (P>.05), with precision ranging from ±0.032 to ±0.050 mm. CS showed significantly higher trueness deviation (0.343 mm; P<.001). With alternative protocols, scanner-dependent differences emerged. PS maintained comparable trueness (0.242 versus 0.245 mm; P>.05). TS showed a significant increase in trueness error (0.215-0.438 mm; P<.001). SM showed statistically similar trueness (0.222 and 0.246 mm; P>.05). CS maintained high trueness deviations (0.391 and 0.386 mm) with precision values of ±0.115 and ±0.081 mm. CONCLUSIONS:When manufacturer-recommended protocols were followed, favorable trueness values were obtained for all scanners. When alternative scanning protocols were employed, only Primescan remained stable across all sites, whereas the other scanners showed protocol-dependent deviations.

Objective: Implant rehabilitation in grafted alveolar clefts requires a complex staged reconstructive approach, and a clinically important yet underexplored question is which patients require additional pre-implant block regrafting after primary grafting has already been completed. This single-centre retrospective cohort study aimed to evaluate whether a history of maxillary advancement is associated with a reduced likelihood of requiring pre-implant block regrafting (defined here as Re-graft 1), and to describe medium-term implant survival outcomes in a cleft implant cohort. Methods: Forty-two patients with Veau class III or IV cleft palate who underwent implant rehabilitation in grafted alveolar cleft sites between 2011 and 2023 were included. A total of 80 dental implants were evaluated at the implant level; analyses of primary grafting outcomes and the need for Re-graft 1 were performed at the patient level. Mean age at implant placement was 21.07 years (range, 17-38 years); mean follow-up was 83 months. Patients were categorised by maxillary advancement history: distraction osteogenesis (n = 11), orthognathic Le Fort I advancement (n = 9), or no advancement (n = 22). Bergland grades were assigned independently by two attending surgeons from postoperative radiographs. Implant outcomes were classified using the ICOI/Misch four-level scale (success, satisfactory survival, compromised survival, failure). Group comparisons used chi-square and Fisher's exact tests. Results: Patients with any maxillary advancement history were significantly less likely to require Re-graft 1: 65.0% of patients with advancement did not require Re-graft 1, compared with 27.3% in the no-advancement group (Fisher's exact p = 0.029; OR = 4.95). Overall implant survival was 93.75%; 58.75% of implants were classified as complete success, and 30.00% as satisfactory survival. Conclusions: In this observational, hypothesis-generating cohort, maxillary advancement history was associated with a lower likelihood of requiring pre-implant block regrafting. Implant rehabilitation showed favorable medium-term survival. These findings are limited by the retrospective single-center design, modest sample size, and absence of multivariable adjustment, and require confirmation in larger prospective studies with standardized regrafting criteria.

Background:. Facial asymmetry includes several etiologies, among them trauma to the condylar area during early childhood and congenital malformations such as hemifacial microsomia. This article describes the management of facial asymmetry in adolescents and young adults using a mandible first approach by distraction osteogenesis, followed by maxillary Le-Fort I as a second stage. Methods:. Eighteen patients 14–25 years of age presented with unilateral hypoplasia of the jaws which manifested clinically by deviation of the chin and canting of the occlusal plane. Etiology included hemifacial microsomia and trauma injuries at early childhood. All patients underwent orthodontic treatment and two phases of surgical treatment. Surgical treatment included unilateral mandibular distraction followed by Le-Fort I osteotomy for alignment of the maxilla. Additional bone graft in the affected side and sliding genioplasty were done as required. Results:. Marked ramal elongation of 18.94 mm concomitant with mandibular forward traction of 12.5 mm was noted while achieving symmetry. In all cases, the maxilla was centered to the midline in proper occlusion. Post distraction, posteroanterior cephalometric radiographs demonstrated elongation of the affected ramus, improvement in facial symmetry, and correction of the occlusal canting. Relapse was minimal based on long-term follow-ups of 47.4 months. Conclusions:. The two-stage surgical approach that includes elongation of the mandible as a first stage followed by adaptation of the maxilla is useful in correcting facial asymmetry. Using this protocol at the correct age (14–18) is very stable, as demonstrated by our results, yet one should always remember the transverse deficiency in the gonial angle requires additional bone grafting or patient specific implants.

The osteogenic potential of mesenchymal stem cells (MSc) in axial spondyloarthritis (AxSpA) depends on the interplay of inflammation and multiple hormonal and local mechanical factors. In this study, MCs, derived from the adipose tissue of a healthy donor, were cultured under or without continuous mechanical load in the osteogenic differentiation medium with or without the addition of testosterone, cocktail of INF-γ/TNF-α/IL-22, or both. Real-time PCR for osteogenic transcription factors demonstrated that in the absence of INF-γ/TNF-α/IL-22, mechanical load causes significant upregulation of SPP1 (osteopontin), while the presence of the inflammatory cytokines almost completely abolishes this effect. In addition, exposure to INF-γ/TNF-α/IL-22 slightly upregulated BMP2 , but suppressed the expression of ALPL , Col1A1 , and SPP1 , reinforcing the hypothesis that the inflammatory environment allows MSc to commit toward the IL-22-driven osteogenic differentiation but can restrict the later stages of osteogenesis. In summary, osteopontin can play a role in the pathogenesis of AxSpA, linking between mechanical load and pathological bone formation.

Background The interplay between the inflammatory part of the disease and osteogenesis in axial spondyloarthritis (AxSpA) is incompletely understood. It is believed that inflammation triggers the process of new bone formation on the one hand, but the regulation of these phenomena is distinct on the other. An assumption that disease-related osteoproliferation in AxSpA is governed by the complex interplay of inflammation, hormonal or growth factors, and mechanical load has been made. A recent study demonstrated that a pro-inflammatory environment, consisting of interferon-γ (INF-γ) and tumor necrosis factor-α (TNF-α), allowed IL-22-induced proliferation and migration of mesenchymal stem cells (MSc) [1]. Objectives To examine the influence of continuous mechanical load (CML) on the osteogenic behavior of MSc with or without INF-γ/TNF-α/IL-22 or testosterone exposure. Methods Adipose tissue-derived MCs, characterized by CD90+, CD73+, CD13+, CD45-, CD31-, isolated from the adipose tissue of a healthy donor and kindly donated by Bonus BioGroup, Haifa, Israel, were cultured for two weeks without or under CML of 2 gr/cm2, applied by transparent glass cubes placed on the plates covering the well, in the following conditions: a. osteogenic differentiation medium (ODM) with no additions of cytokines or testosterone; b. ODM with the addition of testosterone, 0.01 µM; c. ODM with the addition of INF-γ (2.5ng/ml), TNF-α (1ng/ml), and IL-22 (0.5ng/ml); d.ODM with the addition of both three cytokines above and testosterone. Real-time PCR for ALPL, RUNX2, SPP1, BMP2, and Col1A1 was performed and analyzed by the ThermoFisher cloud data analysis program (https://thermofisher.com/il/en/home/digital-science/thermo-fisher-connect/all-analysis-modules.html). ΔΔCt and RQ (2-ΔΔCT) were calculated, with the results presented in a histogram graph as fold-change (Figure 1). Results CML induced significant upregulation of SSP1, or osteopontin (OPN), by MSc. However, this effect was almost completely abolished in the presence of INF-γ/TNF-α/IL-22. Conclusion Increased OPN production by MSc can link mechanical load and new bone formation after the resolution of the inflammatory phase in AxSpA. Reference [1]El-Zayadi AA, Jones EA, Churchman SM, et al. Interleukin-22 drives the proliferation, migration and osteogenic differentiation of mesenchymal stem cells: a novel cytokine that could contribute to new bone formation in spondyloarthropathies. Rheumatology (Oxford). 2017;56:488-493. Acknowledgements Genomics Center of Technion, Haifa, Israel, for performing real-time PCR tests for the study. Disclosure of Interests Aniela Shouval: None declared, Marina Brant-Roznavi: None declared, Tal Tamari: None declared, Hagai Hazan-Molina: None declared, Dror Aizenbud: None declared, Shiri Keret: None declared, Leonard Saiegh: None declared, Gleb Slobodin Speakers bureau: Novartis, Abbvie, Pfizer, Eli Lilly, Sanofi, Grant/research support from: Novartis.Figure 1RQ (2-ΔΔCT) for mechanical load effect. Samples without mechanical load were used as a reference.ODM – osteogenic differentiation medium; IFN – interferon-γ; TNF – tumor necrosis factor-α; IL-22 – interleukin-22

Aim of the study: The aim of the study the aim of the study was to analyze the effectiveness of orthodontic space closure treatment in patients with congenitally missing of upper lateral incisors (CMULI). Materials and methods. The study was carried out on a group of 25 patients with CMULI aged between 7-25 years (average age 14.6 years), who presented themselves for CMULI treatment. Fixed orthodontic appliance, protraction facial mask and class III elastics were applied to all patients. The cephalometric radiographs before and after treatment were analyzed to observe if the application of the orthodontic appliance produces dento-alveolar retrusion and the statistical correlations between the studied parameters were analysed. Results. The statistical analysis of the studied variables showed that there are no statistically significant correlations between the initial and final cephalometric values, obtained after the orthodontic treatment. Conclusions The association of fixed orthodontic appliances together with protraction facemask and class III elastics represents an effective method of treatment of congenitally missing of upper lateral incisor.

Introduction: Human teeth are composed mainly of dentin, formed by the odontoblasts. Dentin matrix protein 1 (DMP1) is one of odontoblast differentiation's most important growth fac-tors. Human DMP1 has yet to be completely identified or studied. This study aimed to clone and characterize human DMP1. Materials and methods: The DMP1 gene sequence was prepared and cloned by transfection of human 293 cells. Results: The recombinant DMP1 was purified and characterized. Conclusion: The results suggested its future use in dental tissue regeneration and tissue engineer-ing. & COPY; 2023 The Authors. Production and hosting by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Supernumerary teeth and odontomas are obstacles for spontaneous tooth eruption and may result in impaction. The aim of the study is to present a conservative treatment approach for impacted teeth following surgical obstruction removal by reviewing three treatment modalities: surgery only, which involves the surgical removal of the obstruction and the spontaneous eruption; surgery with immediate traction, which includes surgery combined with immediate active orthodontic brace cementation and traction; and surgery with delayed traction, which combines a surgical procedure of obstacle removal and orthodontic brace cementation with follow-up for the spontaneous eruption. The first two modalities require orthodontic traction either by an additional surgical procedure for orthodontic brace cementation, or combined with the surgical obstacle removal. With the third approach, clinical follow-up is performed via connected ligature wire elongation applied during the surgical procedure for the spontaneous emergence of the impacted tooth. Active orthodontic traction is only employed if the tooth fails to erupt. The visual follow-up via wire elongation serves as a reference during the emergence of the impacted teeth and reduces the need for radiographic examination. The surgical-orthodontic approach saves both further surgery and orthodontics (spontaneous eruption) or further surgery (in failure to erupt).

Background The effect of improvement in prenatal identification of cleft lip or palate (CL/P) on termination of pregnancy (TOP) worldwide is scarcely reported. Our aim was to assess changes in the prevalence of cleft palate attributed to the high access and availability of prenatal advanced screening and pregnancy termination in Israel. Methods A retrospective study was conducted on CL/P patients which were treated in our institute and born between January 2000 and December 2018. Clinical and demographic data were extracted from medical records. Data on TOP were collected based on accessible information from the Ministry of Health. Cleft palate severity was evaluated using the Veau Classification. Results The study was conducted on 258 patients. Higher incidence of Veau II and III was evident throughout the examined period (2000-2018). However, when evaluating the incidence per year, we found that the incidence of severe cases (Veau III and IV) decreased every year showing a major decline of 60% in the last decade, whereas mild cases (Veau type I and II) demonstrated a marked increase of 90%. Regarding the incidence of abortions in Israel, a decrease of 30% was observed in the last two decades, meanwhile a substantial increase was detected in the rate of abortions related to physical malformations of the fetus. Additionally, the number of late terminations due to physical malformations significantly increased in the last decade. Conclusions Significant decrease was observed in the incidence of severe cleft palate cases in the last decade. Concurrently, we found a substantial increase in percentage of abortions performed due to physical malformations. We suggest that these changes might be attributed to the accessibility of advanced prenatal screening and pregnancy termination in Israel under the social healthcare system.

Tooth gemination is often presented clinically and radiologically as merged crowns or “megadonts” with or without a longitudinal fissure, single root, and a single pulp chamber. The increased mesiodistal width of these teeth results in poor anterior aesthetics, anterior crowding, and incisor rotation. Our aim is to present a conservative non-extraction orthodontic approach that provides both good aesthetics and long-term stability. It aims to achieve extra space to incorporate the megadonts into the dental arch and to exceed “super” class I dental relationships. Accordingly, this study shows that geminated teeth were successfully retained by means of conservative non-extraction orthodontic mechanotherapy and without premolar extractions or enamel reduction. It demonstrated stability during a long-term 15-year follow-up, in addition to high patient satisfaction, good aesthetics, and periodontal health. The solution protocol is definitive and achieved the aesthetic, psychological, and functional objectives at a feasible cost. Thus, this treatment has proven to be preferable to other alternative surgical prosthodontic and endodontic approaches in terms of its long-term stability, and by providing a solution that does not necessitate further multidisciplinary interventions. Dental practitioners in the fields of pediatric dentistry, endodontics and prosthodontics should be well aware of this option.

Chapter 17 Clear Aligners in the Treatment of Impacted Teeth Dror Aizenbud, Dror AizenbudSearch for more papers by this authorTarek El-Bialy, Tarek El-BialySearch for more papers by this authorHagai Hazan Molina, Hagai Hazan MolinaSearch for more papers by this author Dror Aizenbud, Dror AizenbudSearch for more papers by this authorTarek El-Bialy, Tarek El-BialySearch for more papers by this authorHagai Hazan Molina, Hagai Hazan MolinaSearch for more papers by this author Adrian Becker BDS, LDS RCS, DDO RCPS, Adrian Becker BDS, LDS RCS, DDO RCPS Clinical Associate Professor Emeritus Department of Orthodontics, Hebrew University–Hadassah School of Dental Medicine, Jerusalem, IsraelSearch for more papers by this author Book Author(s):Adrian Becker BDS, LDS RCS, DDO RCPS, Adrian Becker BDS, LDS RCS, DDO RCPS Clinical Associate Professor Emeritus Department of Orthodontics, Hebrew University–Hadassah School of Dental Medicine, Jerusalem, IsraelSearch for more papers by this author First published: 07 January 2022 https://doi.org/10.1002/9781119565406.ch17 AboutPDFPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShareShare a linkShare onFacebookTwitterLinked InRedditWechat Summary A clear aligner system was introduced into the orthodontic armamentarium in 1997 by two graduate students at Stanford University. This chapter aims to illustrate the advances made in the treatment of impacted teeth with clear aligners, and their efficacy and suitability for use in the field of digital orthodontics. In clear aligner therapy, a software program is used that simulates the sequence of orthodontic tooth movement from an existing malocclusion towards the final planned occlusion. Impacted teeth are usually presented with space loss in thearea of the impaction due to a missing permanent tooth and/or an over-retained primary tooth. By using digital planning software, the clinician may design and plan the arch preparation solely with clear aligners. Space regaining using clear aligners may be performed inthe sagittal direction by sequential distalization, sequential mesialization or proclination, and in the transverse direction by dental arch expansion. Orthodontic Treatment of Impacted Teeth, Fourth Edition RelatedInformation

OBJECTIVE:The objective was to investigate the effect of extracorporeal shock wave therapy (ESWT) on the magnitude of orthodontic tooth movement, in a rat model, based on a previously established treatment protocol.DESIGN:In conjunction with orthodontic force commencement, rats underwent ESWT. The amount of tooth movement along with different microarchitectural parameters were measured after three weeks by means of microcomputed tomography. In addition, the percentage of cells expressing vascular endothelial growth factor, the number of tartrate-resistant acid phosphatase (TRAP) positive cells/area and blood vessel density were evaluated both for the pressure and tension sides.RESULTS:The addition of ESWT to the orthodontic force after three weeks more than doubled the average tooth movement. The addition of ESWT on the pressure side induced a significant decrease in volumetric bone mineral density. Blood vessel density and the number of TRAP positive cells were higher after the application of ESWT.CONCLUSION:The induction of ESWT during orthodontic tooth movement in a rat model increases the rate of tooth movement by accelerating bone resorption on the pressure side and possibly enhances bone formation on the tension side.

Objectives: Successful aesthetic repair of the bilateral cleft lip and palate (BCLP) is one of the most challenging cases encountered by a surgeon. This challenge is heightened when the premaxilla is anteriorly protruded in relation lateral maxillary segments. Our aim is to demonstrate a useful technique for reducing the cleft size before secondary lip repair. We use a premaxillary osteotomy to posteriorly reposition the premaxilla between the lateral segments Methods: Six patients with BCLP underwent repositioning of the protruded premaxilla. Five patients had previous primary lip closure procedures with unsatisfactory results. The cleft size was reduced by premaxillary osteotomy from nasal septum and partial removal of the vertical vomer. The osteotomized premaxilla was then repositioned, fixed with a custom-made orthodontic appliance. Following this procedure, the lip was closed in a traditional fashion. Results: All patients demonstrated satisfying lip closure without tension. In each case, the premaxilla was vital and exhibited partial stabilization during follow-up Conclusions: In this study the authors demonstrate the usefulness of a premaxillary segment setback as an adjunct to improved function and aesthetics in bilateral lip repair. This method serves as useful technique for previously unsuccessful closure of BCLP

Tooth root resorption is an unwanted result of orthodontic tooth movement, and it can be expressed by a reduction in cementum thickness. The aim of this experimental study was to evaluate the effect of intraligamentary injection of osteogenic-induced gingival fibroblasts (OIGF) on cellular and acellular tooth root cementum thickness in modeled orthodontic tooth movement. Six beagle dogs were used in the study. All the upper and lower third and fourth premolars were subjected to mechanical loading for 4 weeks, which induced orthodontic tooth movement. Fifteen premolars were assigned to the OIGF group, which received a single OIGF injection through the periodontal ligament near the root apex (n = 7 teeth), and to the control group, which received a single injection of Dulbecco's modified eagle's medium in the periapical area (n = 8 teeth). The evaluation of histomorphometry was performed to assess the thicknesses of cellular and acellular cementum at the root apex and four bilateral sites distal to the apex. We found no statistically significant enhancing effects of gingival fibroblasts on either cellular or acellular cementum thicknesses when compared with the control group. We conclude that a single intraligamentary injection of OIGF does not stimulate the formation of tooth root cementum in the dog model of orthodontic tooth movement. Thus, OIGF is unlikely to prevent orthodontic-induced tooth root resorption.

OBJECTIVES To screen a sample of Moldavian schoolchildren to establish their periodontal condition using the Pathfinder study design of the World Health Organization (WHO). METHODS Two cohorts - 12- and 15-year schoolchildren - were screened in 12 schools around the country: four schools in the capital city; four more schools in two other larger cities (two schools in each city); and four village schools (one school in each village). In addition to demographic data, the periodontal parameters dental plaque, calculus and bleeding on probing (BOP) were collected. Periodontal pocket depth (PPD) was also measured but only in the cohort of 15-year-old schoolchildren. Measurements were recorded for the six Ramfjord index teeth. RESULTS In total, 720 children were surveyed: 365 (50.7%) were 12 years of age and 355 (49.3%) were 15 years of age; 351 (48.8%) were girls and 369 (51.2%) were boys; 490 (68%) lived in an urban area and 230 (32%) lived in a rural area. Only 4.5% of 15-year-old children presented with a pocket depth of ≥3.5 mm. Children who lived in rural areas had higher plaque scores than children who lived in urban areas (64.8% vs. 54.1%, P = 0.007). In addition, children who lived in urban areas had significantly less calculus (P = 0.047) and shallower PPDs (P = 0.019). Deeper PPD was associated with higher PI and calculus scores. CONCLUSIONS Moderate-to-deep periodontal pockets were not uncommon in children in the 15-year-old cohort. Periodontal status was worse in children from rural areas than in children from urban areas. It is therefore suggested that an educational programme, together with preventive and interceptive protocols, should be adopted in early adolescence and especially in rural regions.

INTRODUCTION:Basic research in orthodontics is commonly conducted in rodents. However, experimental studies on orthodontic tooth movement (OTM) lack a standard method to examine OTM and periodontal changes. This study describes a unifying protocol for the analysis of OTM and associated bone microarchitectural changes in mice using microcomputed tomography (µCT).METHODS:Mice (10 animals/group) were divided into control and OTM groups. OTM was generated by anchoring a nickel-titanium closed-coil spring to the upper incisors to pull the upper left first molar. A third group of TNFα -/- mice was added since these are known to have slower OTM. Using µCT, we implemented and tested a number of methods to measure OTM distance and examine 3D bone morphometric parameters associated with OTM in mice.RESULTS:In total, we tested five methods to measure the OTM distance in mice. The results indicated that measuring the intermolar diastema, and assessing tooth movement relative to the anterior root of the zygomatic arch, displayed the lowest standard deviation and enabled optimal detection of intergroup differences. We also developed two protocols for µCT analysis of the periradicular bone that yielded no false-positive results. Our results revealed that including the width of the periodontal ligament rather than excluding it from the region of interest in mice detected more statistically significant differences in the morphometric parameters between the OTM and control sides and between WT and TNFα -/- mice despite more subtle differences.CONCLUSIONS:We, therefore, propose new guidelines for a standardized μCT-based method to analyse OTM and the extent of the periradicular bone structural changes in mice.

Objective: An esthetic facial soft tissue profile is an important objective of contemporary orthodontics. The extent to which clinicians and the public agree on profiles that are esthetically acceptable versus profiles recommended for treatment is unclear. Thus, this work examined the profile considered esthetic by laypeople and general dental practitioners compared to orthodontists. Method and materials: An Israeli balanced male-female group comprising 284 participants (orthodontists [n = 86], general dental practitioners [n = 64], laypeople [n = 134]) rated the attractiveness of five standardized masculine and feminine profiles presented in standardized silhouettes ranging from concave to convex. Results: Laypeople see no esthetic difference between masculine and feminine profiles, and prefer moderately concave over moderately convex and severely concave over severely convex profiles. While all raters preferred the straight silhouettes, orthodontists rated them significantly higher than general dental practitioners (P < .0001) or laypeople (P < .020). Similar to the general population, orthodontists gave higher ratings to concave profiles for masculine profiles, but significantly lower ratings for feminine profiles.The severely convex male profile was the least attractive to clinicians and laypeople. There was a significant difference in the attractiveness of the female profile between practitioners (P < .001 and P < .02 for general dental practitioners and orthodontists, respectively) and laypeople. Conclusions:The findings suggest that orthodontic training and clinical adherence to strict beauty norms results in more critical judgment of female attractiveness, which may affect orthodontic treatment. They indicate trends that reflect changes in recent decades in the public perception of facial beauty, which may affect patient expectations of treatment outcomes.

Sustained mechanical forces applied to tissue are known to shape local immunity. In the oral mucosa, mechanical stress, either naturally induced by masticatory forces or externally via mechanical loading during orthodontic tooth movement (OTM), is translated, in part, by T cells to alveolar bone resorption. Nevertheless, despite being considered critical for OTM, depletion of CD4+ and CD8+ T cells is reported to have no impact on tooth movement, thus questioning the function of αβT cells in OTM-associated bone resorption. To further address the role of T cells in OTM, we first characterized the leukocytes residing in the periodontal ligament (PDL), the tissue of interest during OTM, and compared it to the neighboring gingiva. Unlike the gingiva, monocytes and neutrophils represent the major leukocytes of the PDL. These myeloid cells were also the main leukocytes in the PDL of germ-free mice, although at lower levels than SPF mice. T lymphocytes were more enriched in the gingiva than the PDL, yet in both tissues, the relative fraction of the γδT cells was higher than the αβ T cells. We thus sought to examine the role of γδT cells in OTM. γδT cells residing in the PDL were mainly Vγ6+ and produced interleukin (IL)–17A but not interferon-γ. Using Tcrd-GDL mice allowing conditional ablation of γδT cells in vivo, we demonstrate that OTM was greatly diminished in the absence of γδT cells. Further analysis revealed that ablation of γδT cells decreased early IL-17A expression, monocyte and neutrophil recruitment, and the expression of the osteoclastogenic molecule receptor activator of nuclear factor–κβ ligand. This, eventually, resulted in reduced numbers of osteoclasts in the pressure site during OTM. Collectively, our data suggest that γδT cells are essential in OTM for translating orthodontic mechanical forces to bone resorption, required for relocating the tooth in the alveolar bone.