Prevalence and characteristics of and risk factors for impacted teeth with ankylosis and replacement resorption - a retrospective, 3D-radiographic assessment.

BACKGROUND: Large variation in the prevalence of ankylosis and replacement resorption (ARR) is reported in the literature and most studies have relatively small patient numbers. The present retrospective study aimed to provide an overview on prevalence, location of, and associated risk factors with ARR based on a large sample of computed tomography (CT) / cone beam computed tomography (CBCT) scans of impacted teeth. The results should allow clinicians to better estimate the risk of ARR at impacted teeth. METHODS: The CT/CBCT scans of 5764 patients of a single center in Central Europe were screened with predefined eligibility criteria. The following parameters were recorded for the finally included population: gender, age, tooth type/position, number of impacted teeth per patient, and presence/absence of ARR. For teeth with ARR the tooth location in reference to the dental arch, tooth angulation, and part of the tooth affected by ARR were additionally registered. RESULTS: Altogether, 4142 patients with 7170 impacted teeth were included. ARR was diagnosed at 187 impacted teeth (2.6%) of 157 patients (3.7%); 58% of these patients were female and the number of teeth with ARR per patient ranged from 1 to 10. Depending on the tooth type the prevalence ranged from 0 (upper first premolars, lower central and lateral incisors) to 41.2% (upper first molars). ARR was detected at the crown (57.2%), root (32.1%), or at both (10.7%). After correcting for confounders, the odds for ARR significantly increased with higher age; further, incisors and first/second molars had the highest odds for ARR, while wisdom teeth had the lowest. More specifically, for 20-year-old patients the risk for ARR at impacted incisors and first/second molars ranged from 7.7 to 10.8%, but it approximately tripled to 27.3-35.5% for 40-year-old patients. In addition, female patients had significantly less often ARR at the root, while with increasing age the root was significantly more often affected by ARR than the crown. CONCLUSION: ARR at impacted teeth is indeed a rare event, i.e., only 2.6% of 7170 impacted teeth were ankylosed with signs of replacement resorption. On the patient level, higher age significantly increased the odds for ARR and on the tooth level, incisors and first/second molars had the highest odds for ARR, while wisdom teeth had the lowest.

Three-dimensional position of impacted maxillary canines: Prevalence, associated pathology and introduction to a new classification system.

Classification of impacted maxillary canines facilitates interdisciplinary communication. Cone beam computed tomography (CBCT) has proven to be superior for the localization of impacted maxillary canines compared with 2D imaging. The purpose of this study was to retrospectively classify a cohort of impacted maxillary canines, using a new developed 3D classification for impacted maxillary canines that is easy to use and does not require complex analysis of the 3D images. A retrospective cohort study was designed, containing CBCT data of 130 patients (male/female: 48/82; median age 16) with a total of 162 impacted maxillary canines. The proposed classification was based on four criteria: vertical crown position, mesiodistal tooth postion, bucco-lingual crown position, and associated pathology. For all included patients, classification criteria were identified and correlated to treatment selection using a newly developed 3D classification. The most common positions were vertical crown position at apical one third of neighboring teeth, mesiodistal tooth angulation, and palatal crown position. The most frequent associated pathologies were dilaceration of the root and resorption of a neighboring tooth. Significant associations among classification variables and treatment options were observed. Limitations of this study are the retrospective design. CBCT enabled 3D assessment of impacted maxillary canines allowing a classification system that may have an impact on further treatment strategies.

Incidence and distribution of deciduous molar ankylosis, a longitudinal study.

AIM: To study incidence and distribution of deciduous molar ankylosis. MATERIALS AND METHODS: study design: longitudinal retrospective study. A total of 512 consecutive subjects (aged 5 to 15 years) were examined at the Orthodontics and Paediatric Dentistry Department of the Genoa University School of Dentistry; for each subject an ortopantomography x-ray was taken. RESULTS: Thirty-four children were affected by deciduous molars ankylosis (6.6%). A statistically significant difference was revealed between the distributions: the lower deciduous molars were ankylosed more frequently than the upper ones (P < 0.001); the second deciduous molars were ankylosed more frequently than the first molars (P < 0.001). No statistical significance was found between sex and number of infraoccluded teeth (P = 0.74). CONCLUSION: This study found an incidence of deciduous molar ankylosis of about 6.6%; the lower deciduous molars and second deciduous molars were ankylosed more frequently (P < 0.001).

A retrospective study of 889 injured permanent teeth.

The aim of this study was to investigate pre-injury factors, causes of dental injuries and healing complications after traumatic injuries to permanent teeth. The analysed sample comprised 889 permanent teeth of 384 patients, who were treated in the Dentistry Department in Faculty Hospital in Pilsen. Enamel-dentin fractures [233 teeth (26.2%)] and lateral luxations [207 teeth (23.3%)] were the most frequent injuries. The age of the patients at the time of injury varied between 7 and 65 years. Predominantly, children were affected [587 injured teeth (66.0%)]. The most frequent causes of injuries in patients older than 11 years were various sport activities, predominantly bicycling. Pulp necrosis was observed in 239 teeth (26.9%). It was the most frequent post-traumatic complication in all types of dental traumas. Teeth with a completed root formation demonstrated a higher prevalence of pulp necrosis than teeth with an incomplete root formation in all types of luxation injuries. External root resorption was observed in 144 teeth. The rate of inflammatory resorption differed between the various types of luxation injuries (extrusive luxation 5.6%, lateral luxation 11.6%, intrusive luxation 33.3%). Following avulsion and replantation, active inflammatory resorptions were diagnosed in 13 (26.5%) of 49 replanted teeth and ankylosis/replacement resorptions were observed in 21 (42.9%) of 49 replanted teeth. After avulsion, primarily, immature teeth were affected by these complications. Within the observation period of 5 years, 39 teeth (4.4%) had to be removed (16 teeth with root fractures, 19 avulsed and replanted teeth, 3 luxated teeth, 1 tooth with crown-root fracture).

Tooth ankylosis in deciduous teeth of children with cleft lip and/or palate

Este estudo avaliou a prevalência de anquilose dentária em molares decíduos de portadores de fissura de lábio e/ou palato, brancos, de ambos os sexos, com idade entre 5 e 12 anos. Um total de 330 pacientes atendidos no Hospital de Reabilitação de Anomalias Craniofaciais da Universidade de São Paulo para tratamento de rotina foi clinicamente avaliado. A prevalência de anquilose foi analisada em relação a gênero, idade (5-7; 8-10; 11-12 anos), tipo de fissura, dente e arco afetados. O grupo total demonstrou prevalência de 18%, sem diferença estatística entre gêneros e tipos de fissura, sendo mais acometido o arco mandibular, o primeiro molar inferior e as faixas etárias de 8 a 10 e de 11 a 12 anos. Os resultados estão de acordo com aqueles observados na literatura para pacientes sem fissuras, destacando a ausência da influência das fissuras na prevalência de anquilose. Isso reforça a importância do diagnóstico precoce dessa anomalia e do tratamento de escolha, que são similares aos de pacientes sem fissuras.

Tooth ankylosis in deciduous teeth of children with cleft lip and/or palate.

The present study aimed at evaluating the prevalence of tooth ankylosis in deciduous molars of Caucasian children with cleft lip and/or palate aged 5 to 12 years, of both genders. A total of 330 patients seen at the Hospital for Rehabilitation of Craniofacial Anomalies of the University of São Paulo for routine treatment were clinically evaluated. The prevalence of ankylosis was analyzed in relation to gender, age range (5-7, 8-10, 11-12 years), type of cleft, affected tooth and arch. The total group showed a prevalence of 18%, with no statistical difference between genders and among types of cleft; ankylosis was more often in the mandibular arch, lower first molars and among children in the age ranges 8-10 and 11-12 years. The results agreed with those observed in the related literature for patients without clefts, pointing out the absence of influence of the cleft on the prevalence of ankylosis. This reinforces the importance of early diagnosis of this anomaly and of the treatment of choice, which are similar in patients with or without clefts.