Factors influencing root resorption in retained mandibular second deciduous molars with congenital absence of second premolars: a cross-sectional study.

BACKGROUND: There are currently no studies that quantitatively compare the relationship of root resorption to the patient's systemic history or craniofacial and intraoral morphology, especially in relation to possible host factors. Thus, this study aimed to clarify the factors associated with root resorption in retained mandibular second deciduous molars with the congenital absence of second premolars and predict the prognosis of retained mandibular second deciduous molars. METHODS: A cohort of 5547 patients who visited the orthodontic clinic at Tokyo Medical and Dental University Dental Hospital between 2013 and 2022 was screened. Lateral cephalometric radiographs, panoramic radiographs, upper and lower dental models, and orthodontic treatment questionnaires were used as reference materials to apply the inclusion and exclusion criteria. Ultimately, 111 patients were included in the analyses. The patients were divided into two groups based on the root resorption levels of the retained mandibular second deciduous molars. Those with less root resorption were classified under the good condition (GC) group, whereas those with more root resorption were classified under the poor condition (PC) group. Demographic, clinical, and cephalometric parameters were compared between the groups. A multivariate logistic regression model was used to predict the probability of root resorption. RESULTS: The prevalence of congenitally missing mandibular second premolars with persistent mandibular second deciduous molars was 2.0%. In a total of 111 patients, eighty-three teeth (53.2%) were classified into the GC group, whereas 73 teeth (46.8%) were classified into the PC group. The Frankfort-mandibular plane angle (FMA) [odds ratio (OR): 0.87], Frankfort-mandibular incisor angle (FMIA) (OR: 0.93), overbite (OR: 1.38), adjacent interdental space (OR: 1.46), distance from occlusal plane (OR: 0.80), and caries treatment (OR: 7.05) were significantly associated with the root resorption of the retained mandibular second deciduous molars. CONCLUSIONS: Our findings suggest that skeletal morphology, oral morphological patterns, and history contribute to root resorption in retained mandibular second deciduous teeth with congenital absence of subsequent permanent teeth.

Clinical analysis of nonsyndromic oligodontia phenotypes.

OBJECTIVES: To provide references, this study investigated the clinical characteristics of patients with nonsyndromic oligodontia. METHODS: The information of 178 patients with oligodontia was collected, including histories, oral examinations, and panoramic radiographs. Tooth agenesis characteristics were calculated and evaluated. All the data were statistically analyzed with SPSS 24.0 software. RESULTS: No significant difference in the number of missing teeth was found between sexes nor between the right and left sides, and congenitally missing teeth affected the maxillary arch (P<0.05). The highest prevalence of tooth agenesis was observed in the mandibular second premolars. In the maxillary arch, the most common pattern of tooth agenesis was agenesis of the bilateral first and second premolars. The agenesis of the bilateral second premolars was observed in the mandibular arch. The prevalence of a symmetric pattern between the right and left quadrants was significantly higher than that of matched patterns between the maxillary and mandibular antagonistic quadrants. Approximately 16.85% of patients with nonsyndromic oligodontia were affected by other tooth-related anomalies. CONCLUSIONS: The common patterns of tooth agenesis were successfully identified in patients with nonsyndromic oligodontia. Dentists need to provide multidisciplinary treatments for patients with nonsyndromic oligodontia because of variations in occluding and full-mouth tooth agenesis patterns.

The ectopic mandibular canines can start tooth formation in three different locations: a case series study based on single orthopantomograms from 47 individuals.

INTRODUCTION: A former study on orthopantomograms from young children with abnormal dental development (not canine ectopia) demonstrated that the tooth bud of the mandibular canine, compared to a stable longitudinal canine axis, could be located normally, anteriorly or posteriorly, with close relation to the first premolar. AIM: The aim of the present study is to analyse on orthopantomograms if the canine axis can demonstrate where the ectopic mandibular canine started tooth formation. MATERIALS: The material consists of orthopantomograms with ectopic mandibular canines and presence of primary mandibular canines from 47 cases (29 cases 9-21 years old and 18 cases with unknown ages). The primary canines demonstrated from minor apical resorption to more severe apical resorption. METHODS: Based on canine maturity, location of the canine axes and the interrelationships between the roots of the permanent canine and first premolar, the location from where the canine started tooth formation was determined. Canine maturity. Maturity stage below half root length and maturity stage above half root length revealed that 11 ectopic canines had less than half root length and 36 cases more than half root length. Canine axes. The canine axis, through the length of the primary canines Ax, is inserted on drawings of the orthopantomograms using the tracing programme Inkscape®. Interrelationship between roots. By visual inspection, the distance between the canine and first premolar was designated close distance, normal distance and extended distance. RESULTS: The results are divided into 3 groups. Group 1: The initial site of the permanent ectopic canine is located within the canine axis (6 cases). Group 2: The initial site of the permanent ectopic canine is located posterior to the canine axis (36 cases). Group 3: The initial site of the permanent ectopic canine is located anterior to the canine axis (5 cases). CONCLUSION: The study explained that the canine axis could divide cases of ectopic canines into three groups according to the location from where tooth formation starts. For getting closer to the pattern of the ectopic canine eruption, it is necessary to analyse series of orthopantomograms taken from the same individual over several years.

Patterns and sexual dimorphism of non-syndromic hypodontia among a French orthodontic population.

OBJECTIVES: This retrospective study aimed to estimate the prevalence of non-syndromic congenitally missing teeth (CMT) and to explore the frequency of CMT patterns in a French orthodontic population. In addition, the study sought to assess sex-based differences in CMT patterns. DESIGN: Panoramic radiographs of 4569 orthodontic patients between 9 and 21 years-old performed over a 16-year period (2006-2022) were examined to identify non-syndromic tooth agenesis, excluding third molars. A chi-square test or a Fisher exact test were used to determine the difference in the prevalence of tooth agenesis between sex and between arches. RESULTS: Tooth agenesis was observed in 7.3% of the sample (7.9% for females and 6.6% for males). Approximately 86% of the included subjects presented 1 or 2 missing teeth. Single tooth agenesis was significantly more frequent in females than males (p = 0.002, χ2). In total, 23 of the 67 different patterns of CMT observed, were present more than once. 75.5% of male patients and 79.5% of female patients presented one or both missing lateral incisors or second premolars, rarely affected at the same time. This study showed no sex difference in the patterns of tooth agenesis. LIMITATIONS: This study has limitations due to its retrospective nature and our findings apply solely to an orthodontic population from a white ethnic background. CONCLUSIONS: Clinicians should be aware of this particular incisor/premolar phenotype regardless of biological sex. Issues associated with congenitally missing teeth can be managed more effectively with early teenage diagnosis.

Status of retained deciduous second molars in subjects with agenesis of second premolars in relation to age.

AIM: To evaluate the presence and status of retained DM2 without permanent successors in relation to age. BACKGROUND: Preservation of retained deciduous second molars (DM2) can be applied to treat congenital absence of second premolars (PM2). However, the consequences of caries and progressing root resorption or infraocclusion may affect their survival. METHODS: Panoramic radiographs of individuals >10 years of age with agenesis of at least one PM2 were evaluated and divided into three groups according to age. The presence and location of retained DM2, caries/restorations, infraocclusion and root resorption were investigated. RESULTS: A total of 131 subjects with PM2 agenesis were included (mean age: 13 years 11 months). The majority were missing one or two PM2. In total, 174 retained DM2 were present (33%), and their incidence was higher in the younger age groups. Caries/restorations were found in 88 (50.6%) and infraocclusion in 21 (12%) retained DM2. The roots were resorbed mostly for ½ of the root length (35%). CONCLUSION: Long-term prognosis of retained DM2 without permanent successors seems uncertain, especially within the younger age group. In individuals older than 17 years, the prognosis for a healthy DM2 is favorable, if no distinct infraocclusion or extensive root resorption is present.

Current Management of Dens Evaginatus Teeth Based on Pulpal Diagnosis.

INTRODUCTION: Dens evaginatus (DE) is a dental anomaly with a supernumerary tubercle projection that typically contains dentin and pulp tissue. However, the tubercle projection can fracture, exposing the dentin and potentially the dental pulp, which induces pulpal diseases. Managing DE should be primarily based on the clinical diagnosis of the pulp. METHODS: The literature search in prevalence, prophylaxis, and management of dens evaginatus was performed in PubMed database as well as by manual search, in which the related contents were collected and descriptively analyzed. RESULTS: Of the 264 searched literatures, 62 articles were included for this scoping review. The prophylactic management of the tubercle of DE teeth with a normal pulp should be performed as early as possible by the prep-and-fill technique or the reinforcement technique to preserve tooth vitality and continued root development, with the former reported to be superior compared with the latter. Furthermore, DE teeth with reversible pulpitis should be managed with the prep-and-fill technique. For DE teeth with irreversible pulpitis, vital pulp therapy, ie, partial or full/coronal pulpotomy, should be considered when the pulpal inflammation is limited to the coronal pulp to preserve the vitality of the radicular pulp that induces apexogenesis. A pulpectomy should be performed if the pulpal inflammation has progressed into the radicular pulp. For DE teeth with pulpal necrosis (or after pulpectomy) and immature roots, mineral trioxide aggregate apexification or regenerative endodontic procedures are the treatment options. For DE teeth with pulpal necrosis and complete root formation, nonsurgical root canal treatment is the treatment of choice. A flow chart of the decision-making for managing DE teeth based on pulpal diagnosis is proposed. CONCLUSION: DE teeth should be properly managed, by prophylaxis or treatment, depending on pulpal diagnosis and related factors.

Mesiodistal angulation and developmental stages of unerupted mandibular second premolars in nonsyndromic oligodontia.

INTRODUCTION: Oligodontia is a serious developmental dental anomaly that requires long-term multidisciplinary treatment, but its clinical characteristics are not well understood because it is rare. This study evaluated the mesiodistal angulation and developmental stages of unerupted mandibular second premolars (MnP2s) in orthodontic patients with nonsyndromic oligodontia. METHODS: Thirty-seven patients with oligodontia with at least 1 unerupted MnP2 in Demirjian's developmental stages between D and G were selected. Age- and sex-matched patients without tooth agenesis, excluding third molars, were selected as the control group. Mesiodistal angulation between the long axis of the available MnP2 and the mandibular plane was measured on panoramic radiographs. RESULTS: The MnP2 was significantly more distally angulated in the oligodontia group than in the control group. The developmental stage of the MnP2 in the oligodontia group was significantly delayed (1.04 ± 0.26 years; 95% confidence interval, 0.53-1.55 years). No correlation between the mesiodistal angulation and the developmental stage of the MnP2 was found in both groups. CONCLUSIONS: Significant distal angulation and delayed developmental stages of MnP2s were found in patients with nonsyndromic oligodontia compared with age- and sex-matched patients without agenesis of permanent teeth, excluding third molars. However, no significant correlation was found between them. Regardless of the severity of the distal angulation of MnP2, observing delayed dental development in each patient is important.

How Does Hypodontia Compare in Nonsyndromic Pierre Robin Sequence Versus Isolated Cleft Palate and Isolated Cleft Lip?

OBJECTIVE: To assess the prevalence and patterns of hypodontia in nonsyndromic Pierre Robin sequence (PRS) and compare it with hypodontia in nonsyndromic isolated cleft palates and isolated cleft lips. DESIGN: Retrospective cohort study. SETTING: Alder Hey Children's Hospital, United Kingdom. PATIENTS: Patients with nonsyndromic PRS (group 1), isolated cleft palate (group 2), and isolated cleft lip (group 3). MAIN OUTCOME MEASURES: Hypodontia in the permanent dentition assessed from orthopantomographs. RESULTS: A total of 154 patients were included. Group 1 had the highest incidence of hypodontia with 47% having at least one tooth congenitally absent. Groups 2 and 3 had reduced rates of hypodontia with 27% and 19% of the groups missing teeth, respectively; 93% of cases of hypodontia in group 1 involved the absence of at least one second premolar. Of these patients, there was found to be bilateral agenesis of second premolars in 50% of cases. CONCLUSIONS: Patients with PRS and cleft palates are more likely to have hypodontia than those with isolated cleft palates or unilateral cleft lips. Patients with PRS have more severe hypodontia than those with isolated cleft palates or unilateral cleft lips. Bilateral agenesis of lower second premolars is a commonly seen pattern among patients with PRS. In this large UK study, a similar prevalence and pattern of hypodontia to other nonsyndromic PRS populations worldwide has been demonstrated.

Regeneración ósea guiada con dentina autógena tras la exodoncia de un premolar retenido en posición invertida: evaluación a 4 meses de un caso clínico / Guided bone regeneration with autogenous dentin after extraction of an impacted bicuspidin inverse position: 4-month evaluation of a clinical case

Introducción: el empleo de técnicas regenerativas tras la extracción de dientes retenidos ha mostrado su eficacia con diversos materiales de regeneración, al asociarse al empleo de membranas, pero en los últimos años se ha descrito el empleo de dentina autógena en procedimientos de regeneración ósea, mostrando unos resultados favorables. Caso clínico: se presenta un caso clínico de una mujer de 20 años, sin antecedentes médico-quirúrgicos de interés, que acudió a consulta remitida por su ortodoncista, para la extracción de un premolar maxilar retenido, en posición invertida. Tras la extracción del premolar y del tercer molar inferior retenidos, se obtuvo dentina procedente de ambos, para la regeneración ósea guiada del defecto resultante de la extracción del premolar, realizando revisiones a la semana y a los 4 meses de la intervención. Conclusiones: la dentina autógena demuestra ser un biomaterial biocompatible, adecuado para procedimientos de regeneración ósea guiada, tras la extracción de dientes retenidos, como alternativa a otros biomateriales. (AU)

Introduction: regenerative bone techniques after impacted teeth extraction have shown to be effective with different materials, when used in conjunction with membranes, but in the last few years, autogenous dentin has been used in bone regeneration procedures, having promising results. Clinical case: a clinical case of a 20-year-old woman is presented, with no interesting medical record, who went to dental clinic for removal of an inverse maxillary bicuspid retained. After maxillary bicuspid and lower third molar extractions, autogenous dentin was obtained from both teeth, to perform a guided bone regeneration of the bicuspid defect. A week and 4-month check-up were carried out. Conclusion: autogenous dentin has shown to be a biocompatible material, adequate for guided bone regeneration procedures, after extraction of impacted teeth, as an alternative to other biomaterials. (AU)

Tooth agenesis patterns in Japanese orthodontic patients with nonsyndromic oligodontia.

INTRODUCTION: Tooth agenesis is the most common dental anomaly in humans and is often found in orthodontic patients. However, severe tooth agenesis (oligodontia) is rare and its characteristics are poorly understood. This study aimed to investigate tooth agenesis patterns of Japanese orthodontic patients with nonsyndromic oligodontia. METHODS: Panoramic radiographs of 228 orthodontic patients (141 females, 87 males) with nonsyndromic oligodontia were selected and permanent tooth agenesis excluding third molars was evaluated. Influence of cutoff age was tested, tooth agenesis patterns for each quadrant were calculated, and antagonistic maxillary and mandibular quadrants were merged as the occluding tooth agenesis pattern. Full-mouth tooth agenesis patterns were also evaluated. RESULTS: The highest prevalence of tooth agenesis was observed in maxillary and mandibular second premolars, followed by maxillary first premolars. Prevalence of a symmetric pattern between right and left quadrants was significantly higher than matched patterns between maxillary and mandibular antagonistic quadrants. Among 456 possible tooth agenesis patterns, 51 and 49 patterns were observed for the maxillary and mandibular quadrants, respectively, but 215 patterns for the occluding patterns were observed. In addition, 180 full-mouth tooth agenesis patterns were observed in the 228 patients. CONCLUSIONS: Distinct characteristics in highly ranked patterns were observed compared with studies from other geographic areas, especially in the maxillary arch. Occluding and full-mouth tooth agenesis patterns showed wide variation, suggesting difficulty in orthodontic diagnosis.

Autotransplantation of premolars and space closure in a patient with inflamed sinuses.

Congenital absence of permanent teeth can be treated by means of dental implants and prosthetics. Tooth autotransplantation is an alternative in growing patients because continued eruption of the transplanted tooth and associated alveolar bone growth can be expected. This clinical report presents tooth autotransplantation in a 10-year-old boy with chronic maxillary rhinosinusitis, diagnosed by the department of otorhinolaryngology. The patient's mandibular second premolars were transplanted to a congenitally edentulous maxillary premolar region. There was insufficient alveolar bone during transplantation because of pneumatization, but normal root development with vertical alveolar bone growth was observed during a 3-year follow-up. Healing of the transplant in the right side without closing of the apex and without signs of obliteration after 4 years is exceptional.

[Study of skeletal features in congenital hypodontia]. / Veleszületett csírahiánnyal társuló skeletalis eltérések vizsgálata.

INTRODUCTION: The incidence of congenital hypodontia is increasing in daily practice. Early diagnosis of this dental disorder and the associated skeletal malocclusions is crucial for successful and stable final rehabilitation. AIM: Comparison of cephalometric findings of patients with hypodontia of 1-4 teeth with the measurement results of the control group without teeth agenesis. MATERIAL AND METHOD: We evaluated the lateral X-ray of 41 patients with 1-4 teeth agenesis selected from patients referred for orthodontic treatment to the Orthodontic Department of the University of Medicine and Pharmacy from Târgu Mures within a two-year period. The results were compared with the values of the age and sex matched control group. RESULTS: Bilateral upper incisor and lower bicuspid were missing in most of the hypodontia cases. When looking at the NSGn angle predicting the growth direction of the mandible, statistically significant differences were found between the male (p = 0.012), the front (p = 0.010) and the hypodontia group (p = 0.024) and the control group. Regarding the ANB angle, which shows the sagittal position of the maxilla to the mandible, statistically significant differences were found between the subgroups (women, men, anterior or posterior hypodontia) and the control group. CONCLUSION: Larger number of skeletal class 3 and vertical hypodivergent tendency were observed in the hypodontia group. Orv Hetil. 2019; 160(6): 214-219.

Patterns of congenitally missing teeth of non-syndromic and syndromic patients treated at a single-center over the past thirty years.

OBJECTIVES: Literature regarding congenitally-missing-teeth (CMT) is lacking especially on CMT-patterns. Thus, the aim of this study was to present an in-depth analysis of 843 patients with CMT treated at a single-center over the past thirty years. DESIGN: Age, date-of-birth-year, gender, medical- and family-history, CMT-types, -numbers, -severity, -region, -symmetry, -patterns using the tooth agenesis code (TAC), and -growth types of all clinically and radiographically diagnosed CMT-patients were collected. Age and occurrence of syndromes were used to divide CMT-patients into non-syndromic patients older than nine years (group1) and syndromic CMT-patients (group2). Groups were compared especially regarding gender and CMT-severity. RESULTS: The average CMT-number per patient was 5.5 (group1, n = 816, 59.9% female) and 15.1 (group2, n = 27, 29.6% female). There were significant less male (40.1% vs. 70.4%, respectively; P = 0.002) as well as significantly less male-oligodontia (44.8% vs. 73.9%, respectively; P = 0.009) in group1 than in group2. Group1 resulted in decreased prevalence of similar CMT-patterns with severity; the most prevalent CMT was the 2nd premolar; there were no significant differences between the right and left side, whereas more CMT affected the maxilla; the majority of patients presented with bilateral-CMT (82.8%); females were more affected by CMT but more males had severer forms; certain single CMT differed by gender, and CMT was related to first-grade-relatives. CONCLUSION: The majority of CMT-patients presented with hypodontia. Furthermore, same CMT-patterns seem more like to be present in patients with milder forms of tooth agenesis. Gender-specific association regarding CMT-number, severity groups, and single CMT were detected.

A novel deletion mutation, c.1296delT in the BCOR gene, is associated with oculo-facio-cardio-dental syndrome.

The purpose of the present study was to analyze the clinical phenotypes of a girl with oculo-facio-cardio-dental (OFCD) syndrome and to identify the potential pathogenic mutation responsible for her disease. The patient underwent detailed clinical examinations and phenotype data were collected over a follow-up period of 9 years. Mutation analysis of the candidate gene BCOR was performed with polymerase chain reaction and Sanger sequencing. BCOR of 60 unrelated normal individuals were also sequenced as a control group. Clinical phenotyping and follow-up study results indicate that this patient had multiple system anomalies including ocular, facial, cardiac, dental, and limb malformations. In addition, papilloma of the choroid plexus was identified, which represents the first report of this phenotype in an OFCD patient. A novel deletion mutation, c.1296delT in exon 4 of the BCOR gene, was identified in this patient and was not found in her parents or in 60 normal unrelated individuals. This deletion was a frameshift mutation and is proposed to encode a premature stop codon, thus producing a truncated protein. Our patient fitted the diagnostic criteria for OFCD syndrome and we report the first papilloma of the choroid plexus in an OFCD patient, expanding the recognized phenotypic spectrum of this disease. Meanwhile, we identified a novel deletion mutation that may cause OFCD syndrome.

Contemporary endodontic treatment choices for adult patients with dens evaginatus and apical periodontitis: a case report with a 2-year follow-up.

Dens evaginatus (DE) frequently leads to pulp exposure and subsequent pulpal inflammation, pulpal necrosis, and periapical inflammation. This case report describes the application of regenerative endodontic therapy and mineral trioxide aggregate (MTA) apexification in a 22-year-old man with mandibular second premolars affected by DE and apical periodontitis. Regenerative endodontic therapy was performed after thorough debridement and placement of calcium hydroxide in the root canal of the left premolar. In contrast, an apical plug of MTA was placed prior to gutta percha compaction in the root canal of the right premolar. Both teeth were restored with adhesive composite resin. A 2-year follow-up examination revealed complete periapical healing.

Quality of occlusal outcome following space closure in cases of lower second premolar aplasia using lingual orthodontic molar mesialization without maxillary counterbalancing extraction.

BACKGROUND: Controlled space closure in cases of isolated lower second premolar aplasia (ILSPA) without maxillary counterbalancing extraction is challenging. Anterior anchorage loss may occur during space closure resulting in compromised occlusal results in terms of an absence of proper canine guidance during laterotrusive mandible movements. In order to evaluate the effectiveness of Herbst telescope anchorage in combination with double-cable, pull mechanics and a completely customized lingual appliance for orthodontic space management in cases of ILSPA, we tested the null hypothesis that there is a significant deterioration in the sagittal canine relationship towards an Angle-Class-II occlusion expressed as a loss of anterior anchorage following space closure with molar mesialization. METHODS: Twenty-five consecutively de-bonded subjects (female / male 17 / 8; aged at T0 (start of MB Tx) 12.3 to 20.6 years; mean age 15.0 / SD 1.7 years) were included in this retrospective analysis using the inclusion criteria of least of one lower second premolar aplasia; completed treatment with a totally customized lingual appliance (CCLA) in combination with Herbst telescopes. Exclusion criteria were the absence of counterbalancing maxillary extractions, as well as additional tooth aplasia other than lower second premolars. A total of 33 single, lower premolar aplasia space closures (right / left sided 17 / 16) were assessed using plaster casts and intra-oral photographs scaled to the plaster casts, at bonding (T0), Herbst insertion (T1), following gap closure (T2) and de-bonding (T3). Parallelism of roots was controlled by panoramic x-rays at T3. RESULTS: The mean aplasia space at T0 was 7.5 mm (SD 2.6). Complete space closure was achieved in all 33 situations. The null hypothesis was rejected. There was a significant improvement in the initial canine relationships (mean 3.5 mm distal occlusion at T0) to a mean 0.1 mm at T3. When evaluated against the individual treatment plan, the following amounts of planned improvements were achieved: space closure 100%, canine relationship 97.5%, overjet 93.9%, overbite 96.4%, parallel roots in space closure site 93.9%. CONCLUSION: Herbst telescope anchorage in combination with double-cable pull mechanics and a CCLA for orthodontic space closure can deliver predictable, high-quality treatment results.

Frequency of missing teeth and reduction of mesiodistal tooth width in Japanese patients with tooth agenesis.

BACKGROUND: Tooth agenesis can involve one or more congenitally missing teeth (CMT) and is the most common congenital dental anomalies in humans. Tooth agenesis and reduction of mesiodistal tooth width are reportedly associated, suggesting that the pathogenesis of the two conditions is related. The current study analyzed the frequency of tooth agenesis and mesiodistal tooth width in cases of hypodontia (1-5 CMT) and oligodontia (≥ 6 CMT) in Japanese patients based on the hypothesis that reductions in mesiodistal tooth width are more frequently associated with oligodontia than hypodontia. METHODS: Japanese patients with tooth agenesis were divided into hypodontia cases (60 female and 25 male, mean age 19.6 years, mean CMT number 1.31 ± 1.65) and oligodontia cases (26 female and 25 male, mean age 14.6 years, mean CMT number 8.07 ± 2.39). Controls included patients with a skeletal class I relationship and no CMT (female and 60 male, mean age 20.8 years). Dental casts and orthopantomograms were used to analyze the CMT frequency and mesiodistal tooth width for each group. The Kruskal-Wallis test, the Mann-Whitney U test, and Spearman's rank correlation were used for statistical analysis. RESULTS: In the hypodontia group, mandibular second premolars were the most frequently missing tooth type (25.9%), followed by mandibular and maxillary lateral incisors (19.4 and 17.1%, respectively). In the oligodontia group, mandibular second premolars were the most frequently missing tooth type (88.2%), followed by maxillary second premolars (87.3%) and first premolars (63.7%). In female subjects in the hypodontia group, only maxillary lateral incisors and mandibular first molars were significantly smaller than those of the female control subjects. In contrast, in the oligodontia group, more tooth types were significantly smaller than those of the control, for both sexes. Except for maxillary second premolars in female subjects, correlations were apparent for all tooth types in both sexes. CONCLUSIONS: Compared to hypodontia, more tooth types exhibited reduced mesiodistal tooth width in oligodontia. Correlations between CMT number and mesiodistal tooth width support the hypothesis that reduction of mesiodistal tooth width are more frequently observed in Japanese oligodontia patients than in Japanese hypodontia patients.

[Maxillary first premolar with four canals: a case report].

This article presented a case of discovering and diagnosing three roots with four canals of the maxillary first premolar. We found and located the extra root canal by clinical diagnosis, careful observation during the operation, and multiangle X-ray. We further confirmed the existence of the three roots with four canals with the help of cone-beam computed tomography. Finally, we verified the success of the high-quality root-canal therapy through root optical microscopy.

Root canal preparation in 3-rooted maxillary premolars through hand, rotary, and reciprocating techniques: a microcomputed tomography evaluation.

Endodontic management of 3-rooted maxillary premolars is a challenge due to their complex anatomy and narrow root canal walls. This study aimed to evaluate, by microcomputed tomography (µCT), the apical enlargement and centering ability promoted by hand, rotary, and reciprocating instrumentation in 3-rooted maxillary premolars. Eighteen teeth were divided into 3 groups (n = 6) according to the preparation technique: crown-down hand, rotary, and reciprocating instrumentation. Instruments with similar apical diameters were used (25 and 40 mm for buccal and palatal canals, respectively). Centering ability and canal enlargement were evaluated through the comparison of µCT images obtained before and after instrumentation. Distances of 0, 2, 4, and 6 mm from the apical stop were considered. Differences between canal areas before and after instrumentation were calculated. In addition, distances between the original canal center and the prepared canal center at the apical stop were measured in both the mesiodistal and buccopalatal directions. Significant differences in enlargement areas and centering ability among the techniques were determined using 2-way analysis of variance and Tukey post hoc test (P > 0.05). Root canal enlargement was similar for all techniques. Excessive enlargement was observed in only a few specimens, and root perforation did not occur. Some specimens presented untreated canal areas. In mesiobuccal and distobuccal roots, reciprocating instrumentation promoted more centered preparations than hand instrumentation when measured in the mesiodistal direction (P > 0.05). There were no other statistically significant differences. The results established that hand, rotary, and reciprocating techniques presented similar safety margins for instrumentation of the apical third of 3-rooted maxillary premolars. Reciprocating instrumentation presented some advantages over hand preparation regarding centering ability.

Regenerative Endodontic Treatment with Orthodontic Treatment in a Tooth with Dens Evaginatus: A Case Report with a 4-year Follow-up.

Dens evaginatus is a developmental tooth anomaly in which an extra cusp or tubercle protrudes on the occlusal surface of the tooth along with some pulpal tissue. Because of the fragile nature of the protrusion, these teeth are often at risk of pulpal exposure. When this occurs in an immature tooth, regenerative endodontic treatment may be a good treatment approach to promote root formation. There is limited literature that documents the occurrence of orthodontic treatment in teeth that have undergone regenerative endodontic therapy using triple antibiotic paste. Here we present a case of an immature premolar tooth with dens evaginatus that was diagnosed with pulp necrosis and chronic apical abscess. The tooth was treated with regenerative endodontic treatment; after which, the patient received orthodontic treatment with fixed appliances for 2 years. The tooth responded favorably to the regenerative endodontic treatment and orthodontic tooth movement. Clinically and radiographically, all the follow-up examinations revealed an asymptomatic tooth with evidence of periapical healing with stunted root development. The tooth remained asymptomatic even after 4 years. The regenerative endodontic procedure (REP) was successful in treating an immature permanent premolar with pulp necrosis and apical periodontitis with dens evaginatus. In this case, the tooth treated with an REP responded to orthodontic treatment similar to the nonendodontically treated teeth. Further studies are recommended to clarify the precise effects of orthodontic treatment on teeth treated with an REP.