Local factors relating to mandibular canine impaction: A retrospective study.

INTRODUCTION: This study aimed to investigate the characteristics of impacted and transmigrated mandibular canines and the association existing between them and some local factors, such as degrees of axial inclination of mandibular incisors, skeletal Class, and mandibular symphysis width. METHODS: A retrospective observational study was performed on the medical records and radiographic examination (panoramic radiographs and lateral cephalograms) of 102 orthodontic patients divided into a study group, with at least 1 impacted mandibular canine (51 subjects) and a control group, without mandibular impaction (51 subjects). A chi-square test, t test, and analysis of variance test analysis were used to analyze the data. RESULTS: Unilateral and buccal impaction and the presence of the deciduous canine were the more prevalent characteristics of impacted canines, whereas 39.2% presented transmigration. Furthermore, the persistence of the deciduous canine on the impaction side (P <0.0001) and the mesial axial inclination of the impacted canine (P <0.0001) were found to be statistically significant characteristics. A statistically significant association was found between the impaction of the mandibular canine and mandibular incisor to the mandibular plane angle (IMPA) (IMPA, 95.8°; P = 0.009). An additional statistically significant association was found with transmigrated canines (IMPA, 96.8°; P = 0.024). CONCLUSIONS: The mesialization of the canine cusp and the persistence of the mandibular deciduous canine are characteristics frequently found in the impaction of the mandibular canine. An accentuated vestibular inclination of the mandibular incisors is significantly associated with mandibular canine impaction.

Chronic sinusitis of odontogenic origin due to an undiagnosed displaced root fragment in the maxillary sinus and the role of cone beam computed tomography in successful management.

Radiographic imaging is an important criteria in diagnosis, treatment planning, and follow-up of an endodontic treatment. When clinicians encounter with diagnostic difficulties and persistent symptoms, the need for advanced diagnostic aids, especially imaging methods, become imperative and essential. This paper reports a case, in which primary endodontic therapy having failed, the patient had persisting symptoms such as pain, swelling, and draining sinus along with signs and symptoms of maxillary sinusitis. Advanced diagnostic aids such as Cone Beam Computed Tomography was useful in accurate identification of the etiology, which was a fractured mesiobuccal root tip of maxillary molar. This is the first reported case, in which the fractured root tip has migrated to the maxillary sinus, during primary endodontic treatment, through the perforated antral floor causing odontogenic sinusitis. The operating microscope helped in the successful completion of endodontic retreatment along with fractured root fragment retrieval.

Desplazamiento accidental del tercer molar al seno maxilar: protocolo de actuación / Accidental displacement of the third molar into the maxillary sinus: action protoco

Introducción: El desplazamiento accidental del tercer molar hacia el seno maxilar es una complicación de la cirugía bucal. La extracción de estos dientes generalmente es compleja debido a la escasa visibilidad, el espacio limitado y la ubicación espacial del diente, por lo que se requiere tener un cuidado meticuloso durante el tratamiento. Objetivo: El objetivo de este artículo ha sido el de establecer un protocolo de actuación basado tanto en el tratamiento quirúrgico como farmacológico, y el seguimiento que este tipo de complicaciones necesita según la literatura. Caso clínico: Se presenta el caso clínico de un varón de 17 años de edad, sin antecedentes médicos de interés, que fue remitido por su odontólogo para proceder a la valoración y extracción quirúrgica del tercer molar superior izquierdo que había sido desplazado al interior del seno maxilar tras el intento de exodoncia, y que producía sintomatología compatible con sinusitis aguda. La exploración radiológica descartó la afectación del resto de senos paranasales y confirmó la obstrucción casi completa del seno maxilar izquierdo. La extracción del cordal se realizó mediante ostectomía de la pared anterior del seno, pautándose tratamiento farmacológico postoperatorio y controles periódicos durante el primer año. Discusión: La terapéutica recomendada para esta complicación incluye la recuperación inmediata del diente, o la extracción posterior mientras la fibrosis se desarrolla en torno al diente desplazado, según sea necesario, tomando en cuenta la infección, el rango limitado del movimiento de la mandíbula, o malestar psicológico del paciente. El tratamiento médico y farmacológico que debe prescribirse según la literatura revisada, para facilitar el drenaje sinusal y el control de la infección. Conclusión: Para evitar este tipo de complicaciones, conviene realizar un estudio radiológico completo en los casos de cercanía del tercer molar superior en las inmediaciones del seno maxilar, y valorar la disposición e inclinación del mismo

Introduction: Accidental displacement of the third molar into the maxillary sinus is one of the complications of oral surgery. These extractions are usually complex due to some factors such as low visibility, limited space and the location of the tooth; so special care on these treatments is required. Objective: To establish an action protocol based on a surgical as well as a pharmacological treatment, and the monitoring that this kind of complications need according to the literature. Clinical case: A 17-year old man, with a noncontributory medical history, was referred to our clinic by a colleague to evaluate and perform a surgical extraction of his upper left third molar, which had been displaced into the maxillary sinus after a failed extraction, and was generating symptoms of acute sinusitis. The radiographic examination dismissed the affectation of the rest of the paranasal sinuses and confirmed the almost totally blockage of the left maxillary sinus. The extraction of this third molar took place by means of an anterior-wall ostectomy of the sinus; afterwards a pharmacological treatment was prescribed and regular control visits along the first year were planned. Discusion:The suggested treatment for this kind of complications involves the immediate recuperation of the tooth or its later extraction meanwhile the fibrosis forms around the displaced tooth, as needed. We have to take into account the infection, the limited mandibular range of movement as well as the patient's psychological discomfort. The medical and pharmacological treatment should be prescribed following the reviewed literature, in order to obtain the sinusal drainage and the infection control. Conclusion: It is convenient to carry out an exhaustive radiological examination in case of close relation between the maxillary third molar and the maxillary sinus as well as evaluate its position and inclination to avoid this kind of complications

Three-dimensional radiographic evaluation of root migration patterns 4-8.5 years after lower third molar coronectomy: a cone beam computed tomography study.

This prospective study in patients with a follow-up of 4-8.5years aimed to describe the long-term, three-dimensional changes of coronectomized lower third molar roots. Pre- and postoperative cone beam computed tomography (CBCT) scans were compared. The distance of root migration, the direction of root translation and rotation, and the amount of bone regeneration at the adjacent second molar and superficially to the third molar root were recorded. Age, gender, time elapsed following surgery, the status of the retained root including, impaction pattern and depth of impaction were tested to check if they were influencing factors for the above outcomes. A total of 57 coronectomized third molars from 44 patients were included. The distance of the mean root migration was 2.82mm, and they predominantly translated mesially (76.8%). Age negatively correlated with the distance of migration. Root remnants with a soft tissue coverage had less bone regenerated at the adjacent second molar (1.27mm vs. 2.95mm) in comparison to their impacted counterparts. Based on the present radiographic results and the absence of any pathological findings, coronectomy can be recommended for selected cases of third molar removal as a safe procedure with favourable long-term outcomes.

Orthodontic treatment in patients with aggressive periodontitis.

INTRODUCTION: Aggressive periodontitis (AP) is a condition that promotes breakdown of the periodontal tissues in a short time. In severe cases, pathologic migration of teeth and tooth loss can occur, producing esthetic and functional problems for the patient. Orthodontic treatment may be recommended to restore esthetics and masticatory function. We assessed the effects of orthodontic movement in the periodontal tissues of treated patients with AP. METHODS: Ten subjects (ages 25.0 ± 5.22 years) with AP received periodontal treatment followed by orthodontic treatment. Maintenance sessions were performed monthly under a strict dental biofilm control. They were compared with 10 periodontally healthy subjects (ages 22.9 ± 5.23 years) who received orthodontic treatment. Probing pocket depth, clinical attachment level, bleeding on probing, and dental plaque index were measured at baseline, after orthodontic treatment, and after 4 months. RESULTS: Statistical analysis showed improvement in all clinical parameters between baseline and 4 months after orthodontic treatment: probing pocket depth (0.29 mm), clinical attachment level (0.38 mm), bleeding on probing (4.0%), and dental plaque index (11%). CONCLUSIONS: The periodontal parameters of the AP patients remained stable during orthodontic treatment under strict biofilm control.

Impacted and transmigrated mandibular canines: an analysis of 3D radiographic imaging data.

OBJECTIVES: Impacted and transmigrated mandibular canines differ greatly in incidence, etiopathology, associated anomalies, and treatment prospects, when compared to their maxillary counterparts. The aim of this study was to provide a detailed analysis of 3D radiographic imaging data of impacted mandibular canines. MATERIALS AND METHODS: In a retrospective cross-sectional study, CT/CBCT data of 88 patients with a total of 94 impacted mandibular canines were analysed. Evaluated parameters included location, morphology, neighbouring structures, associated anomalies, the influence of those factors on mandibular canine transmigration, as well as applied treatment. RESULTS: Transmigration was found to occur in 40.4% of impacted mandibular canines. Transmigrated canines were located significantly more basally and horizontally angulated. Further, transmigration was significantly associated with a lack of contact to adjacent teeth and the canine's apex not contacting the mandibular cortical bone. The overall incidence of root resorptions of adjacent teeth related to impacted mandibular canines was 7.3% and was more likely, if the canine was lingually impacted. While about half of the non-transmigrated impacted canines were orthodontically aligned, half of the transmigrated canines were surgically removed. Monitoring was the second most applied treatment strategy for both groups, and no canines were autotransplantated. CONCLUSIONS: Root resorption of adjacent teeth and transmigration are commonly occurring phenomena related to impacted mandibular canines. CLINICAL RELEVANCE: Treatment often entails the surgical removal of the canine-especially in cases of transmigration. The findings emphasise the importance of early diagnosis and CT/CBCT imaging for further diagnostics and future research of impacted mandibular canines.

Radiographic prognostic factors determining spontaneous space closure after loss of the permanent first molar.

INTRODUCTION: Permanent first molars (PFM) with a poor prognosis are routinely extracted in children throughout the United Kingdom. National guidelines suggest that to achieve spontaneous closure for the mandibular arch, the PFM should be extracted at 8 to 10 years of age, during bifurcation formation of the second molar. The literature is of limited quality and has suggested alternative variables that may be associated with successful space closure. Our aim was to investigate the radiographic prognostic factors associated with space closure after extraction of PFM. Two objectives of the research are reported in this article: to determine factors that might predict space closure of the second molar after extraction of the PFM, and to develop a tool kit to aid clinical decision making. METHODS: We assessed 148 maxillary and 153 mandibular PFM extracted from 81 participants retrospectively. Dental age, second molar developmental stage, second premolar and second molar angulations, and presence or absence of the third molar were assessed on the preextraction orthopantomograms. Outcome was assessed via visual examination, study models, or radiographs. RESULTS: Closure occurred in 89.9% of the maxillary and 49.0% of the mandibular quadrants. Dental age was statistically, but not clinically, significant in the maxillary arch (P <0.05). For the mandibular arch, presence or absence of the third molar and second molar angulation were statistically and clinically significant (P <0.01 and P <0.05, respectively). A tool kit was developed in relation to the mandibular arch variables. CONCLUSIONS: These findings are contradictory to the Royal College of Surgeons guidelines and suggest that the presence of the third molar and a mesially angulated second molar are favorable for space closure. The developed tool kit requires further validity testing.

Quantified diagnostic work-up casts: applications for interdisciplinary treatment planning.

Diagnostic casts that accurately replicate a patient's occlusion are essential for planning comprehensive care and interdisciplinary treatment. These casts can reveal the actual problem in the spatial relationship between the maxilla and the mandible, which may not be apparent on intraoral examination. Duplicate casts can be altered and measured to quantify the extent of the correction necessary for a predictable result. Treatment planning for interdisciplinary cases requires thorough evaluation of the entire problem and solution set as well as coordination of all procedures. Severe problems and invasive treatments require precise treatment planning. This case report illustrates these principles through multiple applications of quantified diagnostic work-up casts for a patient requiring orthognathic surgery, orthodontics, and occlusal adjustment after a mandibular subcondylar fracture.

Open contacts adjacent to dental implant restorations: Etiology, incidence, consequences, and correction.

BACKGROUND: The aim of this investigation was to evaluate the potential causes, clinical significance, and treatment of open contacts between dental implant restorations and adjacent natural teeth. TYPES OF STUDIES REVIEWED: The authors searched the dental literature for clinical trials in humans that addressed the incidence of open contacts that develop after implant restorations are placed next to teeth. RESULTS: The authors found 5 studies in which the investigators addressed the incidence of open contacts after implant restorations are inserted next to teeth. Results from these studies indicated that an interproximal gap developed 34% to 66% of the time after an implant restoration was inserted next to a natural tooth. This event occurred as early as 3 months after prosthetic rehabilitation, usually on the mesial aspect of a restoration. CONCLUSIONS: The occurrence of an interproximal separation next to an implant restoration was greater than anticipated. It appears that force vectors cause tooth movement and an implant functions like an ankylosed tooth. PRACTICAL IMPLICATIONS: Clinicians should inform patients of the potential to develop interproximal gaps adjacent to implant restorations, which may require repair or replacement of implant crowns or rehabilitation of adjacent teeth. Furthermore, steps should be taken to check the continuity of the arch periodically. If the clinician detects an open contact, it is prudent to monitor for signs or symptoms of pathosis so that prosthetic repair of the gap can be initiated, if needed. These problems could add to treatment costs and decrease overall patient satisfaction related to implant treatment.

Lower first permanent molars: developing better predictors of spontaneous space closure.

BACKGROUND: First, first permanent molars (FPMs) of poor prognosis are often planned for extraction at an 'ideal time' so that second permanent molars (SPMs) erupt favourably to replace them. However for lower FPM extractions, timing is not an accurate predictor of success. OBJECTIVE: The aim of this study was to identify additional radiographic factors that could better predict the degree of spontaneous space closure of the lower SPM following FPM extraction. METHODS: Data from a previous study of 127 lower SPMs from 66 patients was re-analysed by incorporating additional radiographic factors. These included calcification stage of the bifurcation of the SPM, position of the second premolar, mesial angulation of SPM in relation to the FPM, and presence of the third permanent molar. Results were analysed using ordered logistic regression. RESULTS: Only 58 per cent of FPMs extracted at the 'ideal time' (SPM development at Demirjian stage E) had complete space closure. The best outcomes resulted from a combination of SPMs not at Demirjian development stage G, together with the presence of mesial angulation of the SPM and presence of the third permanent molar, where 85 per cent of those cases had complete space closure. CONCLUSIONS: Apart from extraction timing of the FPM, consideration must also be given to the presence of the third permanent molar and angulation of the SPM in order to ensure a reliable degree of spontaneous space closure of the lower SPM.

The effect of simvastatin on relapse of tooth movement and bone mineral density in rats measured by a new method using microtomography.

PURPOSE: To evaluate the effect of simvastatin on relapse of tooth movement in rats using microtomography (micro CT), as well as the correlation of bone density with the orthodontic relapse. METHODS: Twenty-five adult male Wistar rats, divided into two groups, had stainless steel springs installed on left maxillary first molar. The molars were moved for 18 days, and after removing the springs, were applied by oral gavage, 5mg/kg of simvastatin in the experimental group for 20 days. Tooth relapse was assessed with a micro CT scanner, and the images chosen through the Data Viewer software 1.5.0.0 had their measurement guides made and checked by the software Image ProR plus 5.1, and compared by Mann-Whitney test. After rats were sacrificed, bone mineral density was evaluated by micro CT through the software CT Analyzer 1.13 and compared by independent T-test, as well as by Spearman correlation test. RESULTS: Relapse and bone mineral density (BMD) was lower in the experimental group than in the control group, however without a statistically significant difference. CONCLUSION: Simvastatin did not inhibit the relapse of tooth movement in rats, and there was no correlation between bone density and orthodontic relapse.

Unusual cases of transmigrated mandibular canines.

Transmigration, an extremely rare anomaly that happens almost exclusively with mandibular canines, is defined as a pre-eruptive migration across the midline. It can lead to various restorative, surgical, orthodontic, and interceptive problems. This condition usually is not related to any painful symptoms and cannot be detected on clinical examination. This article presents 3 cases of transmigration. In 1 case, the right canine was involved, which is considered to be especially rare. This case series also highlights the importance of early diagnosis for the interceptive treatment of transmigration.

Coronectomy of the mandibular third molar: a retrospective study of 185 procedures and the decision to repeat the coronectomy in cases of failure.

PURPOSE: A prevalent complication associated with mandibular third molar extraction is inferior alveolar nerve (IAN) injury. This study evaluated the success rate of coronectomy and, in the event of failure of the procedure, retreatment. PATIENTS AND METHODS: One hundred seventy-three patients underwent 185 coronectomy procedures of the mandibular third molar to prevent IAN injury. The coronectomy was performed along the cementoenamel junction. Residual roots were trimmed 3 to 4 mm below the crest margin. No pulp treatment was performed and the roots were left vital. A postoperative orthopantogram was recorded immediately after the procedure or at follow-up 1 month later. Two additional orthopantographic views were taken at 6- and 12-month follow-up appointments. Statistical analyses were performed to assess differences in root migration, pain, wound healing and failure by age, gender, and time elapsed from coronectomy. Statistical data were considered significant at a P value less than .05. RESULTS: Statistical differences in the migration of residual roots from 6 to 12 months were found. Migration of the roots was found in younger patients. In a total of 10 cases of failure, 4 were treated with repeat coronectomy. The other 6 cases were treated with reoperation (ie, removal of residual roots). CONCLUSION: Immediate postoperative radiographic imaging is recommended, as well as, follow-up evaluation 12 months after surgery. In addition, repeat coronectomy is recommended for cases in which enamel retention is diagnosed to prevent residual roots from becoming infected.

Sequential imaging of an impacted mandibular second premolar migrated from angle to condyle.

Extreme distal migration of impacted teeth to the subcondylar area and condyle is very rare. Using an interesting sequence of radiographs showing the path of the tooth in the mandible, we describe the intrabony migration of a mandibular second premolar from angle to condyle in a young woman. Cone-beam computed tomography was used to establish the precise location of the tooth.

Analysis of spontaneous repositioning of pathologically migrated teeth: a clinical and radiographic study.

OBJECTIVE: Pathologic migration is defined as a change in tooth position, resulting from a disruption of forces that maintain the teeth in the normal position with reference to the skull. Clinical evidence is limited that pathologically migrated teeth may reposition themselves after periodontal therapy. The current study was carried out to determine the frequency of spontaneous repositioning of pathologically migrated teeth after periodontal therapy, and to study the relation between the severity of migration and the degree of repositioning following treatment. METHOD AND MATERIALS: Twenty-five patients aged 20 to 45 years with moderate to severe form of periodontitis presenting 52 diastema sites secondary to pathologic migration involving maxillary anterior teeth participated in the study. After conventional periodontal treatment had been performed, reactive repositioning was assessed by measuring the space between pathologically migrated teeth and adjacent teeth on study models and radiographs obtained at baseline, reevaluation at 4 weeks after scaling and root planing (SRP), 3 months after periodontal surgery, and 6 months from baseline. RESULTS: No changes were noted after SRP. On study models, 88.46% of all sites (46 of 52 sites) demonstrated various degrees of repositioning (both partial closure and complete closure) after periodontal therapy 6 months after baseline. Of these 46 sites, all exhibited improvement after surgical therapy. Labiopalatal repositioning was seen in 32 out of 51 teeth (62.74%). On radiographs, 77.27% of all sites (34 of 44 sites) demonstrated various degrees of repositioning (both partial closure and complete closure) after periodontal therapy 6 months after baseline. Of these 34 sites, all exhibited improvement after surgical therapy. Complete repositioning occurred in 34.61% and partial closure was seen in 53.80%. CONCLUSION: The findings suggest that spontaneous repositioning after periodontal therapy is likely, particularly when light to moderate degrees of pathologic migration are considered.

Lower dental arch changes after bilateral third molar removal.

OBJECTIVE: To evaluate the changes in lower dental arch after bilateral lower third molars removal. MATERIAL AND METHODS: The study group consisted of 30 non-orthodontic patients (mean age 25,5 years, refered for bilateral lower third molars removal. Orthopantomograms and dental casts were made before and 6-8 months after surgical removal of lower third molars. Transversal lower arch widths between lower canines and second premolars and lower arch total tooth size-arch lenght discrepancy were evaluated on dental casts. The angulation of lower second premolars, first and second molars was measured in horizontal and mandibular planes on orthopantomograms. RESULTS: No significant difference of inter-canine and inter-premolar transversal width was noticed. No significant changes were observed in total tooth-size lenght discrepancy, except in S1 segment consisted of first and second premolar and the canine on the right quadrant of the lower dental arch. The angulation of second premolars and first molars did not show any significant changes, however there were statistically significant changes between angulation of lower second molars on both sides. CONCLUSIONS: After bilateral removal of lower third molars, lower second molars awhile showed a tendency to move backwards, but no obvious relationship between the third molar and anterior crowding was observed. Whereas the observation time is short and the patient's age is young and it can not be concluded that lower third molars cause the changes in the dental arch.

Changes in the vertical position of interdental papillae and interseptal bone following the approximation of anterior teeth.

Orthodontic approximation has been proposed as a tool for restoring the lost papilla. A prospective analysis was performed to evaluate the changes in the levels of interdental papilla and alveolar crest following an orthodontic approximation. The levels of interdental papilla and alveolar crest increased; however, the interradicular distance did not influence the level of the interdental papilla or papilla score. Interestingly, the shape of the teeth had a significant impact on the interdental papilla score. In conclusion, orthodontic approximation significantly enhanced the level of the interdental papilla and interproximal alveolar crest, producing an improved esthetic outcome.

Migración de caninos inferiores: reporte de un caso y reseña de la literatura / Transmigrant impacted mandibular canines: report of a case and review of the literature

Objetivo: el objetivo de este trabajo es presentar la exodoncia de un canino inferior izquierdo transpuesto y evaluar las alternativas terapéuticas frente a casos similares. Caso clínico: se desarrolla el caso de una mujer de 30 años de edad con migración del canino inferior izquierdo. Conclusión: se destaca la importancia de otener un diagnóstico clínico y radiográfico temprano para poder realizar tratamientos precoces, a fin de evitar la migración y sus posibles complicaciones. Se enfatiza también la necesidad del estudio anatomopatológico de los tejidos blandos obtenidos con la pieza quirúrgica.(AU)

Clinical and dental computed tomographic evaluation 1 year after coronectomy.

PURPOSE: Coronectomy is performed when contact between the mandibular third molar apex and the inferior alveolar nerve is suspected. The efficacy of coronectomy compared with conventional tooth extraction has been recognized in recent years. However, few studies have reported the postoperative prognosis of roots remaining in the bone or surrounding tissue. Therefore, a clinical evaluation was performed with dental computed tomographic imaging of the coronectomy sites 1 year after the procedure. PATIENTS AND METHODS: This study investigated 101 patients (116 teeth) who underwent a coronectomy from March 2006 through December 2009. They were recalled 1 year later for a clinical evaluation and dental computed tomographic imaging of the coronectomy sites. The clinical evaluation was based on palpation and macroscopic findings. RESULTS: In 99.2% (115 teeth) of the studied cases, the soft tissue distal to the mandibular second molar was healthy and the retained roots were covered by bone. In 1 case (0.8%), an eruption of roots into the oral cavity was observed; however, no inflammation was observed in the nearby soft tissue. In all 116 teeth, no transmission images indicative of periapical lesions, which usually result from necrosis of the pulp, were observed in the apical area of the retained roots. CONCLUSIONS: The absence of transmission images indicative of periapical lesions and the presence of bone covering more than 99.2% (115 teeth) of the retained roots showed a safe postoperative course at the 1-year follow-up after coronectomy.

Changes in molar position associated with missing opposed and/or adjacent tooth: a 12-year study in women.

The aim of this study was to radiographically analyse long-term changes in (i) overeruption of unopposed molars and (ii) tipping of molars with a mesial edentulous space, and whether there is an interaction between the two events. A further aim was to analyse if loss of alveolar bone height might influence overeruption and tipping. The sample consisted of panoramic radiographs taken at an interval of 12 years of 292 subjects from a prospective population study of women. The panoramic radiographs were scanned and analysed. Changes in tipping, overeruption and alveolar bone height of molars and control teeth were measured. The results showed that unopposed molars were more commonly found in the upper jaw and that unopposed molars showed 4·9 times higher risk of overeruption of ≥2 mm (95% CI 1·5-15·3) than opposed molars during the 12-year observation period. The average overeruption for the unopposed molars was 4·5% (s.d. 7·6), which corresponds to approximately 0·9 mm. The degree of overeruption increased with decreased bone support. Molars with a mesial edentulous space were most prevalent in the lower jaw, but neither an edentulous space nor alveolar bone level/bone level change were found to have a significant effect on tipping of the molars. The average mesial tipping was 0·8° (s.d. 5·6). In conclusion, unopposed molars showed a significantly increased risk for overeruption. Molars facing a mesial edentulous space showed a low risk for mesial tipping, but a significant interaction between overeruption and tipping was identified.