Radiographic identification of symptomless mandibular third molars without clinical pericoronitis.

OBJECTIVES: The aim was to identify radiographic characteristics of mandibular third molars in young adults without symptoms or clinical signs of pericoronal infection. MATERIALS AND METHODS: An existing cross-sectional material, including records from clinical oral examination and panoramic radiographs (PANs) of university students, was submitted to retrospective analysis. The outcome variable was a symptomless and clinically pericoronitis-free mandibular third molar. Predictor variables for the third molar were clinical eruption level, pathological signs in the follicle, marginal bone level, radiographic depth in bone, inclination, stage of root development, and available space for eruption. Statistics included χ2 and Mann-Whitney U tests. RESULTS: Analysis included 345 mandibular third molars in 189 participants (20% men, 80% women; mean age 20.7 years; SD ± 0.6). Symptomless and clinically pericoronitis-free mandibular third molars were characterized as follows: clinically unerupted in 78% of teeth, associated with reduced marginal bone level in 70%, located deeper in the bone in 87%, mesially inclined in 73%, and stage of root development incomplete in 68% (p ≤ 0.001 for all). CONCLUSIONS: Radiographic characteristics of symptomless mandibular third molars without clinical pericoronitis in young adults can be assessed from a PAN with 68-87% certainty. CLINICAL RELEVANCE: These findings may prove useful when trying to exclude non-pathological mandibular third molars from diseased teeth.

Etiological Mechanisms and Genetic/Biological Modulation Related to PTH1R in Primary Failure of Tooth Eruption.

Primary failure of eruption (PFE) is a rare disorder that is characterized by the inability of a molar tooth/teeth to erupt to the occlusal plane or to normally react to orthodontic force. This condition is related to hereditary factors and has been extensively researched over many years. However, the etiological mechanisms of pathogenesis are still not fully understood. Evidence from studies on PFE cases has shown that PFE patients may carry parathyroid hormone 1 receptor (PTH1R) gene mutations, and genetic detection can be used to diagnose PFE at an early stage. PTH1R variants can lead to altered protein structure, impaired protein function, and abnormal biological activities of the cells, which may ultimately impact the behavior of teeth, as observed in PFE. Dental follicle cells play a critical role in tooth eruption and root development and are regulated by parathyroid hormone-related peptide (PTHrP)-PTH1R signaling in their differentiation and other activities. PTHrP-PTH1R signaling also regulates the activity of osteoblasts, osteoclasts and odontoclasts during tooth development and eruption. When interference occurs in the PTHrP-PTH1R signaling pathway, the normal function of dental follicles and bone remodeling are impaired. This review provides an overview of PTH1R variants and their correlation with PFE, and highlights that a disruption of PTHrP-PTH1R signaling impairs the normal process of tooth development and eruption, thus providing insight into the underlying mechanisms related to PTH1R and its role in driving PFE.

Pulp stones in unerupted teeth: a retrospective analysis using cone-beam computed tomography.

BACKGROUND: A pulp stone is a calcified mass that develops in the dental pulp of any tooth. Despite many studies examining the relationship between pulp stone formation and non-oral factors, the methods used in these studies have been unable to explain the exact role of these factors alone as distinct from probable effects within the oral cavity environment. Considering that totally unerupted (impacted or developing) teeth are unexposed to the oral cavity's environmental and functional conditions, they provide a more suitable material for studying the effects of these non-oral factors on pulp stone formation. This research study aimed to investigate pulp stones in unerupted teeth and the associated factors in a Saudi subpopulation. METHODS: The study included 644 cone-beam computed tomography images, with 496 (50.9%) maxillary and 479 (49.1%) mandibular teeth. Of the investigated patients, 293 (45.5%) were men, and 351 (54.5%) were women. The age range was 15-76 years. A chi-square test was used to investigate the associations between pulp stones and age, gender, and history of systemic disease and chronic medication use. RESULTS: Pulp stones in unerupted teeth were present in 24.2% of the examined dental jaws and 18.6% of the examined teeth. There was no statistically significant relationship between pulp stones and gender (p > 0.05). A significantly greater percentage of pulp stones were found with increasing age (p = 0.000). Additionally, a significantly increased number of pulp stones was observed in patients with systemic diseases and chronic medications (p < 0.05). CONCLUSIONS: The results support the idea that pulp stones can be present in any type of unerupted tooth. This study provides additional evidence of the increased incidence of pulp stones with age, systemic disease, and chronic medications.

Imaging characteristics of gubernaculum tracts in patients with cleidocranial dysplasia: a computed tomography study.

OBJECTIVES: To elucidate the imaging characteristics of the gubernaculum tract (GT) in patients with cleidocranial dysplasia (CCD) as visualized with computed tomography (CT). STUDY DESIGN: This was a retrospective analysis of the presence and shape of GTs of unerupted permanent teeth and supernumerary teeth on CT in 9 patients with CCD. RESULTS: The overall GT detection rate for unerupted permanent teeth was 83.5% (81/97), with no significant difference between permanent teeth without and with adjacent supernumerary teeth (P = .414). The overall GT detection rate for unerupted supernumerary teeth was 83.1% (49/59). Of the 156 total unerupted teeth analyzed, 83.3% (130/156) were judged to have GTs. No significant difference in detection rate of GTs was found between permanent and supernumerary teeth (P > 0.999). A composite morphology consisted of a single GT for a permanent unerupted tooth with 1 or 2 supernumerary teeth in which the dental follicles of the permanent and supernumerary teeth were confluent. In total, 44 groups consisted of 1 permanent and 1 or 2 supernumerary teeth; 79.5% (35/44) had GTs. CONCLUSIONS: A specific composite structure of GTs and dental follicles may signify that 2 or 3 teeth are derived from a single dental lamina in patients with CCD. In such cases, tooth eruption may fail due to the presence of only 1 GT for multiple teeth.

Pre-eruptive intramural resorption in unerupted teeth: a cone-beam computed tomography evaluation of prevalence and related factors.

OBJECTIVE: Pre-eruptive intramural resorption (PEIR) is defined as an abnormal, well-circumscribed radiolucency within the coronal dentin of the tooth, which is often overlooked in plain radiographs. This study aimed to investigate the prevalence of PEIR and its related factors using cone-beam computed tomography (CBCT). METHODS: CBCT images of 590 unerupted teeth were evaluated for the presence of PEIR, location of PEIR, number of lesions in the affected tooth, PEIR score, tooth angulation, tooth position, and pericoronal space. Binary logistic tests were used to analyze the association between the characteristics of PEIR and the patient's demographic data and related factors. RESULTS: The tooth prevalence of PEIR was 13.6% among unerupted teeth. However, it was noteworthy that 19.2% of the unerupted teeth with PEIR were planned to be kept. PEIR was significantly associated with transverse (p = 0.020), inverted-angulated (p = 0.035), and centrally-positioned teeth (p = 0.043). The severity of PEIR was more pronounced in teeth with distal (p = 0.019), lingual (p = 0.023), or inverted-angulated (p = 0.040) positions, and in the absence of pericoronal space (p = 0.036). CONCLUSION: PEIR should be suspected in transverse, inverted-angulated, centrally positioned unerupted teeth, particularly in molars, with no pericoronal space. Further monitoring through CBCT is recommended in such cases. CLINICAL RELEVANCE: The management of unerupted teeth does not always involve surgical removal. Instead, they could be utilized for artificial eruption or tooth transplantation. The present study emphasizes the significance of early detection of PEIR. Clinical recommendations for screening PEIR in unerupted teeth are also proposed, which can be applied to routine plain radiographs.

Management of preeruptive intracoronal radiolucency (PEIR): a case series with up to 8 years follow-up.

Preeruptive intracoronal radiolucency (PEIR) is a rare dental anomaly often incidentally detected during routine radiographic examinations. This condition manifests as a radiolucent lesion beneath the enamel-dentin junction of unerupted teeth, particularly in mandibular molars, posing diagnostic and management challenges due to its asymptomatic nature. The treatment of PEIR depends on the extent of the lesion and the degree of pulp involvement. Case series: This case series reports on four patients with progressive PEIR. In Cases 1 and 2, lesions were incidentally discovered in panoramic radiographs during orthodontic planning (mandibular permanent second molars), and additional surgical exposure to access the lesion was required as teeth were only partially erupted. Interestingly, in Case 3, the PEIR was not visible in earlier radiographs though the crown of the tooth was already mineralized (mandibular permanent second molar). For Case 4, the tooth presented with symptoms of reversible pulpitis (mandibular permanent first molar). All lesions were treated with indirect pulp capping using biocompat-ible material. The patients were followed up for a period of up to 8 years to evaluate treatment success. Indirect pulp capping and restorations were found to be successful in all four cases in the last follow-up: 1 year (Case 2), 1.4 years (Case 4), 1.5 years (Case 1), and 8 years (Case 3). Conclusion: This case series demonstrates the effectiveness of early intervention via surgical exposure and indirect pulp capping and restoration for managing severe cases of PEIR. However, further research with larger samples and long follow-up is necessary.

Comparison of the different methods of width estimation in unerupted canine and premolars.

BACKGROUND: There are different methods for determining the required space for unerupted teeth. However, the accuracy of these techniques varies depending on ethnic differences. Therefore, the current study was performed to compare the accuracy of four methods for estimating the mesiodistal width of unerupted canines and premolars in a population of northern Iran. METHODS: The present cross-sectional study was conducted on 50 pairs of dental casts of patients aged 12-24 years old. The mesiodistal width of the teeth was measured with a digital caliper by two observers (ICC < 0.9), and the mean value was recorded. The space required for eruption of canines and premolars was obtained by the Tanaka-Johnson formula and the Moyers tables and compared with the actual value by paired t test. RESULTS: The Tanaka-Johnson formula had overestimation in the maxilla and mandible, which was statistically significant (p < 0.001). The values obtained from the Moyers tables in different confidence levels were not accurate. However, the 65% level for the mandible had almost no difference from the actual value (P = 0.996 and r2 = 0.503). Furthermore, linear regression was obtained based on the total mesiodistal width of the maxillary first molar and mandibular central incisor (maxilla: Yx= 0.613X + 2.23 and mandible: Ym= 0.618X + 1.6) and the total mesiodistal width of the mandibular first molar and maxillary central incisor in each jaw (maxilla: Yx = 0.424X + 5.021 and mandible: Ym = 0.447X + 3.631). CONCLUSION: The Tanaka-Johnson method was overestimated in the population of northern Iran. The 85% and 75% confidence levels of the Moyers table have the best clinical results for the maxilla and mandible, respectively. Regression based on maxillary first molars and mandibular central incisors has better results.

Life threatening hemorrhage associated with a dentigerous cyst in a dog: Case report.

Dentigerous cysts are the most common type of odontogenic cysts and arise from an unerupted tooth. These cysts have stereotypical radiographic and clinical findings. They can be extremely invasive but rarely present as a life-threatening emergency. This case report describes the stabilization and treatment of a 6-year-old mixed breed dog with a dentigerous cyst with concurrent life-threatening hemorrhage. The dog presented with severe oral hemorrhage from the mandibular artery and required multiple blood transfusions. It was ultimately diagnosed with a dentigerous cyst. Complications from dental issues and potential life-threatening complications, such as this case, can be prevented by routine annual oral examination and full mouth dental radiographs if an unerupted tooth is suspected.

Forced eruption in impacted teeth: analysis of failed cases and outcome of re-operation.

BACKGROUND: Forced eruption of an impacted tooth usually requires surgical and orthodontic interventions to successfully bring the tooth into the dental arch. The clinical time required for a forced eruption is difficult to predict before treatment begins and success rates are affected by several factors before and after an eruption. This study was conducted to identify factors that affect the success of forced eruption, the duration of orthodontic treatment of impacted teeth, and the reasons for re-operation and forced eruption failure in a various teeth and cases. METHODS: In this retrospective study, the records regarding the forced eruption of 468 teeth in 371 patients from June 2006 to May 2020 at the Advanced General Dentistry Department of Yonsei University Dental Hospital were initially examined. The records of 214 teeth in 178 patients who completed orthodontic treatment were included in the analysis. Data on patient demographics, tooth characteristics, orthodontic treatment duration, re-operations, and failures were collected from electronic medical records. RESULTS: There was a significant difference in age between the success and failure forced eruption. Factors significantly affecting treatment duration were apex formation, position, rotation, and re-operation. Re-operation had a 96% success rate. The average orthodontic treatment duration was 29.99 ± 16.93 months, but the average orthodontic treatment duration for teeth that undergone re-operation was 20.36 ± 11.05 months, which was approximately 9 months shorter. Additionally, there was an interaction effect between rotation and re-operation on the duration of orthodontic treatment. The causes for failure of forced eruption in 6 cases were ankyloses (3 cases), incomplete alignment with the normal dental arch (2 cases), and a significant deviation in the impacted tooth's location (1 case). CONCLUSIONS: To increase the success rate of forced eruption, age should be considered as a priority, and in order to predict the treatment period, the apex formation status, position in the arch, and rotation should be considered in addition to age. When determining re-operation, considering factors such as ankylosis, root curvature, and apex formation can help in the success of orthodontic treatment.

Dentigerous cysts suspected the other odontogenic lesions on panoramic radiography and CT.

Dentigerous cysts are known as the second most common type of cyst in the jaws. The cyst is one of the lesions occurred frequently in the posterior body of the mandible and is often related to the unerupted third molar and forms around the crown of the unerupted tooth attaching at the cementoenamel junction. Such characteristic appearances are the diagnostic points differentiating from ameloblastoma or odontogenic keratocyst. However, it would be hard for us to diagnose it as a dentigerous cyst if the lesion does not show its typical appearance. We experienced two cases of dentigerous cysts which did not form around the crown of the unerupted tooth on radiologically. Both cysts were relatively large and resorbed adjacent teeth roots. Therefore, an ameloblastoma or an odontogenic keratocyst was suspected rather than a dentigerous cyst as the imaging diagnosis. The biopsy revealed that the lesion was a "dentigerous cyst" in one of the cases and "developmental cyst with inflammation" in another case. After the excision, the histopathological diagnosis was a dentigerous cyst with inflammation in both cases. This report shows the two cases of dentigerous cysts focusing on panoramic radiography and CT images. Also, we discuss the differential diagnosis by reconsidering those diagnostic points.