Factors Associated With Successful Surgical Exposure of Impacted Maxillary Canines.

PURPOSE: Impacted maxillary canines occur in up to 3% of the population and their eruption is of great importance in establishing, maintaining the shape, aesthetics, and function of the dental arch. Hence, surgical exposure of canines for the purpose of aligning them is a common surgical procedure. This study identifies the frequency and the statistically significant factors associated with successful surgical exposure of impacted maxillary canines and the relative risk factors for repeat surgery. METHODS: This is a retrospective cohort study of 182 patients who underwent surgical exposure of impacted maxillary canines and orthodontic alignment, over a 5-year period between 2014 and 2018. The variables recorded and analyzed included demographics (age and gender), type of surgery (closed or open exposure), grade of surgeon, and radiographic features on orthopantomogram (canine overlap of adjacent tooth root, vertical canine crown height, canine angulation to midline, position of canine root apex). Outcome data recorded were successful surgical exposure and orthodontic alignment and the need for repeat operation or surgical removal due to ankylosis. The data were analyzed to identify the statistically significant correlates of successful surgical exposure and the relative risk factors associated with repeat surgery. RESULTS: A total of 182 patients and 232 bone-impacted maxillary surgical canine exposures were analyzed, as 50 patients had bilateral impaction. Mean age was 15 years (range = 10-38 years), with 122 (67%) female to 60 (33%) male ratio. Total of 222/232 (96%) impacted maxillary canine teeth were successfully surgically exposed and 10/232 (4%) required re-exposure surgery. Correlates of successful surgical exposures were open exposure technique (P < .002) and reduced distance of vertical canine crown height from alveolar bone margin (P < .033). Relative risk factors for repeat surgery were increased age, male, closed surgical exposure, grade of surgeon, central impaction, increased overlap of adjacent root, increased vertical height, increased angulation to midline, canine apex position above second premolar and procedure done under local anesthetics. CONCLUSIONS: This is the largest impacted maxillary canine study to date which has identified the factors that result in successful surgical exposure, hence allow selection of the patients most suitable for this treatment. Secondly, patients with relative risk factors for repeat surgical intervention may be consented appropriately, triaged for a closer orthodontic follow-up and prioritized for surgery to reduce overall treatment time.

Temporomandibular joint prosthesis as treatment option for mandibular condyle fractures: a systematic review and meta-analysis.

The aim of this study was to perform a systematic review of the literature on the temporomandibular joint (TMJ) prosthesis as a treatment option after mandibular condyle fracture. Three databases were searched (PubMed, Embase, Cochrane Library) and 2670 unique papers were identified. A total of 337 studies were included (121 case reports, 89 case series, and 127 cohort/clinical studies). In total 14,396 patients and 21,560 prostheses were described. Of the 127 cohort or clinical studies, 100 (79%) reported inclusion criteria, 54 (43%) reported exclusion criteria, and 96 (76%) reported the inclusion period. The base population from which patients were recruited was reported in 57 studies (45%). The reason for TMJ prosthesis implantation was reported for 4177 patients (29.0%). A history of condylar fracture was present in 83 patients (2.0%); a history of mandibular trauma was present in 580 patients (13.9%). The meta-analysis showed a pooled prevalence of condylar fracture of 1.6% (95% confidence interval 0.9-2.4%) and a pooled prevalence of trauma or condylar fracture of 11.3% (95% confidence interval 7.1-16.0%). Heterogeneity was highly significant (P < 0.001). The TMJ prosthesis appears to be reserved for patients with persistent pain, bony or fibrous ankylosis, or osteomyelitis after primary closed or open treatment of fractures of the mandibular condyle.

Outcome of intentional replantation of endodontically treated teeth with periapical pathosis: A systematic review and meta-analysis.

The purpose of the present review was to examine success, survival and failure following intentional replantation of endodontically treated teeth with existing periapical pathosis and to determine the factors that might affect the outcome of replantation. Clinical trials, longitudinal studies, case series with >10 cases and at least 1-year follow-up were included. The average rate of success following intentional replantation was 77.23%. Meta-analysis revealed the mean weighted survival to be 85.9% (95% CI: 79.6-91.2) Common complications include inflammatory root resorption (0%-27%) and ankylosis (0%-25%). Variables influencing successful outcome include extra alveolar dry time <15 min; root-end resection (2-3 mm) and cavity preparation (3 mm); manipulation of the tooth using the crown only; and use of an appropriate storage media. The review concludes that intentional replantation is a viable treatment option with acceptable survival rates for endodontically treated teeth with periapical pathosis.

Tooth transplantation and replantation: Biological insights towards therapeutic improvements.

Transplantation and replantation of teeth are effective therapeutic approaches for tooth repositioning and avulsion, respectively. Transplantation involves transplanting an extracted tooth from the original site into another site, regenerating tissue including the periodontal ligament (PDL) and alveolar bone, around the transplanted tooth. Replantation places the avulsed tooth back to its original site, regenerating functional periodontal tissue. In clinical settings, transplantation and replantation result in favorable outcomes with regenerated PDL tissue in many cases. However, they often result in poor outcomes with two major complications: tooth ankylosis and root resorption. In tooth ankylosis, the root surface and alveolar bone are fused, reducing the PDL tissue between them. The root is subjected to remodeling processes and is partially replaced by bone. In severe cases, the resorbed root is completely replaced by bone tissue, which is called as "replacement resorption." Resorption is sometimes accompanied by infection-mediated inflammation. The molecular mechanisms of ankylosis and root resorption remain unclear, although some signaling mechanisms have been proposed. In this mini-review, we summarized the biological basis of repair mechanisms of tissues in transplantation and replantation and the pathogenesis of their healing failure. We also discussed possible therapeutic interventions to improve treatment success rates.

Prospective study of the long-term outcomes and complications after total temporomandibular joint replacement: analysis at 10 years.

This prospective analysis was performed to assess the long-term benefits of the TMJ Concepts joint replacement system in the UK. All patients who had replacement temporomandibular joints (TMJ) with at least 10 years of follow-up were included. The most common primary diagnoses were trauma, multiple previous operations, psoriatic arthritis, rheumatoid arthritis, degenerative disease, and ankylosis. A total of 43 patients (62 joints) were followed up for 10 years (mean age 45, range 22-70 years); 39 were female and four were male. The mean number of previous TMJ procedures was 2.5 (range 0-10). Over the 10 years of follow-up, there were significant improvements in pain score (10-point scale; decreased from 7.4 to 1.7), maximum mouth opening (increased from 21.0 mm to 34.7 mm), and dietary score (10-point scale; increased from 4.1 to 9.5). Joints in two patients failed, one secondary to a local dental infection and one due to reankylosis. None failed due to wear of the prosthesis, whether the prosthesis was standard cobalt-chrome or all-titanium. Total TMJ replacement gives good long-term improvements, both lessening pain and improving function, and is an effective form of management for irreparably damaged joints.

Miniscrew-assisted single-tooth distraction osteogenesis to align an ankylosed infraoccluded maxillary central incisor: A case report.

The ankylosis of permanent incisors is usually caused by trauma. In a growing patient, the ankylosed tooth fails to move along with the vertical growth of the remaining alveolar process, which results in an infraoccluded tooth, gingival margin disharmony and unaesthetic smile.This case report presents an 23-year-old female patient whose maxillary right central incisor (tooth number 11) had been traumatised eight years earlier. A vertical discrepancy of about 4 mm was exhibited between teeth 11 and 12. To reposition the crown and gingival margins of the ankylosed tooth to an ideal level, single-tooth dento-osseous osteotomy and distraction of the block of bone containing the tooth was planned. In order to separate the roots of adjacent teeth for opening a space for osteotomy incision, fixed orthodontic treatment with multibracket appliances was initiated on her maxilla. After five weeks, a single-tooth dento-osseous osteotomy was performed using a piezoelectric device. To move the tooth in occlusal and buccal directions, two temporary anchorage devices (miniscrews) on her mandible and interarch elastics were applied. Approximately three weeks later, the ankylosed tooth successfully had an ideal position-relative to the adjacent teeth-and a harmonious gingival margin was achieved by minor gingivoplasty on all incisors.

Decoronation followed by dental implants placement: fundamentals, applications and explanations.

Dental arches areas with teeth presenting dentoalveolar ankylosis and replacement root resorption can be considered as presenting normal bone, in full physiological remodeling process; and osseointegrated implants can be successfully placed. Bone remodeling will promote osseointegration, regardless of presenting ankylosis and/or replacement root resorption. After 1 to 10 years, all dental tissues will have been replaced by bone. The site, angulation and ideal positioning in the space to place the implant should be dictated exclusively by the clinical convenience, associated with previous planning. One of the advantages of decoronation followed by dental implants placement in ankylosed teeth with replacement resorption is the maintenance of bone volume in the region, both vertical and horizontal. If possible, the buccal part of the root, even if thin, should be preserved in the preparation of the cavity for the implant, as this will maintain gingival tissues looking fully normal for long periods. In the selection of cases for decoronation, the absence of microbial contamination in the region - represented by chronic periapical lesions, presence of fistula, old unconsolidated root fractures and active advanced periodontal disease - is important. Such situations are contraindications to decoronation. However, the occurrence of dentoalveolar ankylosis and replacement resorption without contamination should neither change the planning for implant installation, nor the criteria for choosing the type and brand of dental implant to be used. Failure to decoronate and use dental implants has never been reported.

Primary failure of eruption (PFE): a systematic review.

BACKGROUND: Primary failure of eruption (PFE) is a rare disease defined as incomplete tooth eruption despite the presence of a clear eruption pathway. Orthodontic extrusion is not feasible in this case because it results in ankylosis of teeth. To the best of our knowledge, besides the study of Ahmad et al. (Eur J Orthod 28:535-540, 2006), no study has systematically analysed the clinical features of and factors associated with PFE. Therefore, the aim of this study was to systematically evaluate the current literature (from 2006 to 2017) for new insights and developments on the aetiology, diagnosis, genetics, and treatment options of PFE. METHODS: Following the PRISMA guidelines, a systematic search was performed using the PubMed/Medline database for studies reporting on PFE. The following terms were used: "primary failure of tooth eruption", "primary failure of eruption", "tooth eruption failure", and "PFE". RESULTS: Overall, 17 articles reporting clinical data of 314 patients were identified. In all patients, the molars were affected. In 81 reported cases, both the molars and the premolars were affected by PFE. Further, 38 patients' primary teeth were also affected. In 27 patients, no family members were affected. Additional dental anomalies were observed in 39 patients. A total of 51 different variants of the PTH1R gene associated with PFE were recorded. CONCLUSIONS: Infraocclusion of the posterior teeth, especially if both sides are affected, is the hallmark of PFE. If a patient is affected by PFE, all teeth distal to the most mesial tooth are also affected by PFE. Primary teeth can also be impacted; however, this may not necessarily occur. If a patient is suspected of having PFE, a genetic test for mutation in the PTH1R gene should be recommended prior to any orthodontic treatment to avoid ankylosis. Treatment options depend on the patient's age and the clinical situation, and they must be evaluated individually.

Decoronation followed by dental implants placement: fundamentals, applications and explanations

ABSTRACT Dental arches areas with teeth presenting dentoalveolar ankylosis and replacement root resorption can be considered as presenting normal bone, in full physiological remodeling process; and osseointegrated implants can be successfully placed. Bone remodeling will promote osseointegration, regardless of presenting ankylosis and/or replacement root resorption. After 1 to 10 years, all dental tissues will have been replaced by bone. The site, angulation and ideal positioning in the space to place the implant should be dictated exclusively by the clinical convenience, associated with previous planning. One of the advantages of decoronation followed by dental implants placement in ankylosed teeth with replacement resorption is the maintenance of bone volume in the region, both vertical and horizontal. If possible, the buccal part of the root, even if thin, should be preserved in the preparation of the cavity for the implant, as this will maintain gingival tissues looking fully normal for long periods. In the selection of cases for decoronation, the absence of microbial contamination in the region - represented by chronic periapical lesions, presence of fistula, old unconsolidated root fractures and active advanced periodontal disease - is important. Such situations are contraindications to decoronation. However, the occurrence of dentoalveolar ankylosis and replacement resorption without contamination should neither change the planning for implant installation, nor the criteria for choosing the type and brand of dental implant to be used. Failure to decoronate and use dental implants has never been reported.

RESUMO Áreas dos maxilares com dentes em anquilose alveolodentária e reabsorção dentária por substituição podem ser consideradas como portadoras de osso normal, em pleno processo fisiológico contínuo de remodelação; e os implantes osseointegráveis podem ser aplicados com sucesso. A remodelação óssea promoverá sua osseointegração, independentemente de haver raízes em anquilose e/ou em reabsorção por substituição. Após 1 a 10 anos, todos os tecidos dentários terão sido substituídos por osso. O local, a angulação e o posicionamento ideal no espaço para se colocar o implante devem ser ditados pela conveniência clínica associada, exclusivamente, ao planejamento prévio. Uma das vantagens da decoronação com colocação imediata de implantes em dentes anquilosados e com reabsorção por substituição é a manutenção do volume ósseo na região, tanto vertical quanto horizontalmente. Se possível, deve-se preservar, na preparação da cavidade para o implante, a parte vestibular da raiz, mesmo que fina; isso deixará os tecidos gengivais com aspecto de plena normalidade por longos períodos. O importante na seleção de casos para a decoronação é a ausência de contaminação microbiana na região, representada por lesões periapicais crônicas, presença de fístula, fraturas radiculares antigas não consolidadas e doença periodontal avançada ativa. Essas situações são contraindicações para a decoronação. A ocorrência de anquilose alveolodentária e reabsorção por substituição sem contaminação não deve mudar o planejamento para instalação de implantes, nem mesmo os critérios de escolha do tipo e marca de implante dentário a ser utilizado. Nunca foi relatado fracasso na decoronação e uso de implantes dentários.

Minimally Invasive Treatment of an Ankylosed, Severely Discolored, and Intruded Central Incisor with a Masking Ceramic Veneer: A Clinical Report.

Dental therapy of traumatically ankylosed maxillary anterior teeth with an additional slight root resorption represents a great challenge for the restorative team and requires intensive planning and communication between patient, dentist, orthodontist, periodontist, and dental technician. The inhibition of vertical growth often makes dental intervention indispensable. Porcelain laminate veneers have been successfully used for more than two decades, mainly on anterior teeth, and was the minimally invasive treatment option for the present case report. Preprosthetic planning with a digital approach of the width-length ratio and the red-white esthetics were important prerequisites for a satisfactory treatment result. The treatment goal was clarified using a wax-up and a corresponding template for intraoral verification with a mock-up. The template also served as a preparation guide. Despite all risk factors, including the endodontic treatment, the 3-mm intruded position, and the slight root resorption, the patient and the restorative team decided to restore the situation with two feldspathic-ceramic veneers to provide an esthetic, time-saving, nonsurgical process for the patient.

Ankylosis of Permanent First Molar: Diagnosis by Cone Beam Computed Tomography / Anquilosis del Primer Molar Permanente: Diagnóstico por Tomografía Computarizada con Haz Cónico

ABSTRACT: Ankylosis is an anomaly of tooth eruption characterized by the fusion of cementum and alveolar bone, and may affect from small regions to the entire root surface. Clinical assessment combined with imaging exams can aid diagnosis. Radiographic testing enables assessing only proximal regions of possibly affected roots. Whereas cone beam computed tomography (CBCT) allows a three-dimensional assessment of axial, coronal, and sagittal planes of all dental extension, eliminating thus overlapping images and helping to confirm the correct diagnosis. The present study contains a case report of a male patient with ankylosis in tooth 16 diagnosed by CBCT, aiming at providing information for dentists about this anomaly, its characteristics and situations in which CBCT should be indicated.

RESUMEN: La anquilosis es una anomalía de la erupción del diente caracterizada por la fusión de cemento y hueso alveolar, y puede afectar desde pequeñas regiones hasta toda la superficie de la raíz. La evaluación clínica combinada con los exámenes de imagen puede ayudar a diagnosticar esta anomalía. Las pruebas radiográficas permiten evaluar sólo las regiones proximales de las raíces posiblemente afectadas. La tomografía computarizada de haz de cono (CBCT) permite una evaluación tridimensional de los planos axial, coronal y sagital de toda la extensión dental, eliminando así las imágenes superpuestas y ayudando a confirmar el diagnóstico correcto. En el presente estudio se presenta un reporte de caso de un paciente con anquilosis en el diente 16 diagnosticado por CBCT, con el objetivo de proporcionar información para los dentistas sobre esta anomalía, sus características y situaciones en las que debe indicarse la CBCT.

Spontaneous Alveolar Bone Growth in Ankylosed, Infraoccluded Teeth in Adolescents after Elective Decoronation--A Clinical Case Series.

This article considers a possible solution to prevent or manage spontaneous alveolar bone growth in ankylosed, infraoccluded teeth in adolescents after elective decoronation, allowing replacement resorption to take place, preserving the surrounding alveolar bone and enabling vertical bone development coronal to the decoronated segment. CPD/Clinical Relevance: To illustrate the advantages of decoronation allowing subsequent replacement of infraoccluded ankylosed teeth with implant-retained restorations and minimal aesthetic compromise.

Restorative management of severely ankylosed primary molars.

Severe dentoalveolar ankylosis is an etiological factor for malocclusion. When infraocclusion occurs early, it progresses with time, leading to severe consequences in young children because of compensatory supra-eruption of the antagonist tooth and mesialization of adjacent teeth. Early diagnosis allows for interception of the problem and may prevent orthodontic treatment. The purpose of this manuscript is to report two cases of infraocclusion of primary mandibular second molars that were diagnosed early and were treated with composite resin crowns. The use of indirect composite restorations for ankylosed teeth is a good option for primary teeth with a moderate/ severe degree of ankylosis.

Orthodontic treatment of severe anterior open bite and alveolar bone defect complicated by an ankylosed maxillary central incisor: a case report.

Incisor trauma is common in children, and can cause severe complications during adolescent growth and development. This report describes the treatment of a 16-year-old patient with severe anterior open bite due to ankylosis of the maxillary left incisor after dental trauma as an 8-year-old. No examination or active treatment was undertaken until he was 16 years old. Clinical examination revealed that the maxillary left incisor was severely intruded accompanied by a vertical alveolar bone defect. Orthodontic treatment combined with surgical luxation took 3 years and 7 months. During treatment, the intruded incisor was moved to the occlusal level and the alveolar bone defect was restored, achieving normal occlusion. After two years of retention, the maxillary left incisor was retained in a stable normal position with a slightly reduced overbite. This case demonstrates that surgical luxation with orthodontic traction can be an effective approach, especially when the ankylosed tooth has a single root. Long-term monitoring of orthodontic stability and the maintenance of periodontal health are crucial in the post-treatment period.

Anquilose alveolodentária e subsequente reabsorção por substituição: a colocação de implantes osseointegráveis no mesmo local pode ser feita? / Alveolodental ankylosis and subsequent replacement resorption:can osseointegrated implants be placed in the same location?

os dentes com anquilose alveolodentária naturalmente evoluirão para reabsorção por substituição e, desde que sem contaminação microbiana, devem ser considerados no contexto ósseo como mais uma das estruturas a serem remodeladas continuadamente. A remodelação constante representa uma das características mais marcantes da biologia óssea, haja vista que serve para manter estável o nível sanguíneo de cálcio e outros minerais essenciais à vida. Outra consequência da anquilose alveolodentária é a gradativa infraoclusão do dente envolvido. As áreas ósseas com raízes ou fragmentos radiculares em reabsorção por substituição, desde que livres de contaminação microbiana, podem ser incluídas nas áreas onde se farão alvéolos cirúrgicos para receber implantes osseointegráveis que não atrapalharão o processo de reparo ósseo peri-implantar mais conhecido como osseointegração. Quando contaminada por bactérias e seus produtos, a estrutura radicular deve ser eliminada para depois se avaliar o local para se indicar futuras correções de volume e forma.

Teeth with alveolodental ankylosis naturally evolve to replacement resorption. Provided that they remain free of microbial contamination, these teeth should be considered in the bone context as one more structure that should undergo continuous remodeling. Continuous remodeling is one of the most remarkable characteristics of bone biology, given that it is responsible for keeping blood calcium, as well as other minerals essential to life, levels stable. Another consequence of alveolodental ankylosis is the gradual infraocclusion of the affected tooth. Provided that free of microbial contamination, the areas of bone with root or root fragments under going replacement resorption can remain in the sites where surgical sockets are prepared to receive osseointegrated implants which shall not hinder the process of peri-implant bone repair also known as osseointegration. In the event of being contaminated by bacteria and their byproducts, the root structure should be eliminated. The remaining site should be further assessed to indicate potential corrections of volume and shape.

Treatment of infra-occluded primary molars in patients with dental ageneses.

When dental agenesis is encountered, several treatment solutions can be considered: extraction of the primary tooth and closure of the space or, alternatively, conservation of the space with the primary tooth still on the arch until a prosthesis can be placed. In the presence of premolar agenesis, the corresponding primary molar may be infra-occluded relative to the occlusal plane. This situation complicates the treatment plan. Depending on the clinical setting, it can be useful to restore occlusal contacts using composite overlays. We will demonstrate this treatment option via two clinical cases. Tooth conservation helps maintain the bone volume that will later facilitate placement of an implant and limit extrusion of the antagonists as well as tipping of the neighboring teeth.

Deep submersion: severe phenotype of deciduous-molar infraocclusion with biological associations.

OBJECTIVE: To evaluate the clinical manifestation of and treatment modalities for this severe phenotype of infraocclusion and to examine relationships between deep submersion and the occurrence of other dental anomalies. MATERIALS AND METHODS: The experimental sample consisted of 25 orthodontic patients with at least one deciduous molar in infraocclusion greater than 5 mm. Dental records were used to assess severity of infraocclusion, treatment modality, and presence of other dental anomalies (tooth agenesis, small maxillary lateral incisors, palatally displaced canines, and distal angulation of mandibular second premolars). RESULTS: The sample included 14 females and 11 males, age 7 to 14 years (mean age 10.1 years). The mean infraocclusion depth was 9 mm, with a range of 5-18 mm. The crowns of the adjacent teeth were severely tilted toward the infraoccluded tooth, space was lost in the dental arch, and the successor premolars were impacted in all cases. Treatment consisted of space regaining, surgical extraction of the deciduous molar, and space maintenance. The impacted premolar erupted spontaneously in 95% of the cases. There was a significant increase in prevalence of dental anomalies in the deep-submersion sample compared with that of reference values (P < .001). CONCLUSIONS: The treatment modality used in this sample resulted in spontaneous eruption of the impacted premolar in most cases. Markers for early diagnosis of deep submersion include other dental anomalies, severe tilt of adjacent teeth, and local space loss. The increased prevalence of other dental anomalies supports a shared genetic etiology.

Inter-relations between infraocclusion of primary mandibular molars, tipping of adjacent teeth, and alveolar bone height.

PURPOSE: The purpose of this study was to examine inter-relations between infraocclusion of primary mandibular molars, tipping of adjacent teeth, and alveolar bone height of infraoccluded teeth. METHODS: A total of 402 periapical radiographs of infraoccluded primary mandibular molars were reviewed. Infraocclusion, alveolar bone height, and tipping of adjacent teeth were measured. RESULTS: Infraocclusion was most prevalent among primary mandibular first molars. The amount of infraocclusion was most profound among primary mandibular second molars (2.79±1.25). The shortest distal alveolar crest (reflected by the highest distance between the cementoenamel junction and bone crest) was observed among infraoccluded primary mandibular first molars (0.9±0.92). The permanent mandibular first molar and the primary mandibular first molar demonstrated the maximum tipping mesially and distally. CONCLUSIONS: Infraocclusion of primary mandibular molars, tipping of adjacent teeth, and alveolar bone height of the infraoccluded teeth are inter-related.

Management of ankylosed primary molars with premolar successors: a systematic review.

BACKGROUND: The authors conducted a systematic review to determine the clinical prognosis of and methods of managing ankylosed primary molars with permanent successors. METHODS: The authors searched electronic databases (PubMed, Scopus, MEDLINE, Cumulative Index to Nursing and Allied Health Literature, Web of Science, Cochrane Database of Systematic Reviews and Google Scholar) up to April 2012 with the assistance of a librarian specializing in health sciences databases. They also searched the gray literature. They selected clinical studies in which investigators assessed the prognosis of ankylosed primary molars with permanent successors; they also hand searched references of the selected articles to identify any additional studies that the electronic search may have missed. RESULTS: The authors identified 3,529 original articles from the electronic database search and none from the hand search. Once selection criteria were applied, only four articles met all inclusion criteria and were included. The number of patients studied ranged from 15 to 107. The number of ankylosed primary molars investigated ranged from 26 to 263. CONCLUSIONS: Ankylosed primary molars often manifest with mild to moderate progressive infraocclusion. Conservative monitoring of ankylosed primary molars is recommended. The clinician should consider extraction if the permanent successor has an altered path of eruption, if the ankylosed primary molar is severely infraoccluded with the adjacent teeth tipping to prevent the successor from erupting, or both. The ankylosed molar often exfoliates spontaneously within six months; however, when exfoliation is more delayed, arch-length loss, occlusal disturbance, hooked roots or impaction of permanent successors may occur. Practical Implications. Ankylosed primary molars initially should be monitored closely for up to six months. If they do not exfoliate spontaneously, they should be removed, because arch-length loss, alveolar bone defects, impacted permanent successors and occlusal disturbances often occur when the removal is delayed.