Root fusion in molars: incidence and sex linkage

The morphology of permanent maxillary first molars evaluated by cone-beam computed tomography among a Yemeni population

BACKGROUND

The study's objective was to use CBCT to ascertain the root and root canal anatomy of the permanent maxillary first molars in a Yemeni population. It was considered how gender affected the prevalence of root canal morphology.

METHODS

A sample of 373 CBCT records of maxillary permanent first molars belonging to 373 Yemeni individuals (162 males and 211 females) aged between 12 and 65 years were included in this study. Using CBCT on the teeth, the root form and canal morphology for each root based on Vertucci's classification were evaluated. The distribution of MB2 occurrence was documented. The prevalence and resemblance of the men and females were investigated. The Chi-square test was performed to evaluate the findings.

RESULTS

Of the 373 maxillary first molars studied, the three separated root form was found in 94.9% of the studied MFMs while the two fused and one separate root form was found in 4.5%. The majority of the three-rooted MFMs (82.6%) had more than three root canals (four canals in 77.2% and five canals in 5.4%). The prevalence of MB2 was as high as 82.3% of the three-rooted MFMs. Vertucci type II configuration was the most frequent canal type (25%) followed by Vertucci type III (23.1%) and Vertucci type I (17.7%) in the mesiobuccal root. Vertucci type I was the most prevalent canal configuration in the distobuccal root and palatal root of the three-rooted MFMs (96% and 99.5%, respectively).

CONCLUSIONS

The maxillary first molars' root canal morphology indicated notable variations among a Yemeni population. The maxillary first molars of most of the Yemeni participants in this study had three roots and four canals. In light of the high occurrence of MB2 (82.3%) in permanent maxillary first molars, our findings emphasize the need of searching for and using cutting-edge techniques to locate the MB2 canals. Males outnumbered females in proportion.

Retreatment of a C-shaped maxillary second molar: case reports and literature review

The root canal systems of maxillary second molar (MSM) variations are complicated, especially the prevalence of fused roots and consequent merged and C-shaped canals, which represent a clinical challenge because canal configurations can be irregular and unpredictable. The purpose of this article was to present 2 cases with a C-shaped configuration diagnosed during root canal retreatment and perform a literature review of this MSM anatomy. Case 1 reports that two palatal root canals fused into a C-shaped configuration that finally formed an apical foramen, which was classified as Type D. Case 2 reflects the fusion of the distobuccal canal and palatal canal into a C-shaped configuration and the configuration was Type C, which was first reported in a case report. Nonsurgical retreatments were proposed and conducted. Evaluation at a 24-month recall revealed that the two patients were symptom-free, and radiographic examination revealed normal periapical tissue. This report serves to remind clinicians of the complexities of the root canal system and that possible anatomic variation should always be anticipated when formulating an effective root canal treatment plan. The use of CBCT imaging coupled with an operative dental microscope will be helpful in locating and identifying supernumerary canals when a preoperative periapical radiograph shows signs of a fused-rooted MSM.

Assessment of C-Shaped Canal Morphology in Mandibular and Maxillary Second Molars in an Iraqi Subpopulation Using Cone-Beam Computed Tomography

Endodontic treatment is basically dependent on knowledge of the root canal anatomy. The goal of this study was to use cone-beam computed tomography (CBCT) imaging to examine the C-shaped canal configuration of mandibular and maxillary second molars in an Iraqi subpopulation. The prevalence and configurations of C-shaped canals were evaluated in 368 mandibular second molars and 369 maxillary second molars using CBCT scans. The effects of gender, age, and unilateral/bilateral on the presence of C-shaped canals were investigated. Chi-square and Fisher's exact tests were used to determine the level of significance (p ≤ 0.05), and kappa value was used to check reliability of results of the research. In mandibular second molars, the prevalence of C-shaped canals was 17.4%. The prevalence was significantly higher in females (23%) than males (10.4%) using the chi-square test. There is no significant difference in the prevalence of C-shaped canal depending on age and tooth position. The C2 type was the most common (56.3%). This prevalence did not differ with gender, age, or tooth position. In maxillary second molars, C-shaped canals were present in 7.9%. Type I (subtype C) (fusion of 2 root canals MB-DB) was the most common type of fused root (65.5%). There is no significant difference in the prevalence of C-shaped canal depending on the type of fused root, age, and tooth position. The majority of C-shaped canals in mandibular second molars were bilateral in both genders, but unilateral presence was more common in maxillary second molars in both genders. Within the limits of this study, C-shaped canals were found to be more common in mandibular second molars than in maxillary second molars in an Iraqi subpopulation.

New classification for pulp chamber floor anatomy of human molars

Comprehensive knowledge of the entire root canal system is an essential prerequisite for successful routine endodontic treatments. The internal and external morphological configurations of roots and root canals are quite complex. Thus, several classifications have been put forth by researchers to appropriately understand the distinguishable features of root and root canal systems of multirooted teeth. Until now, the researchers have proposed new classification systems for a thorough understanding of the root canal systems, mainly concentrating on the root canal anatomy and anomalies. Moreover, with the advent of newer digital imaging systems, these classifications are more reproducible and relevant. They have further gained importance for the clinicians by acting as an aid in decision-making based on evidence-based dentistry. However, these classifications are primarily focused on the root canals, but none have assessed the anatomy of the pulp chamber floor. This review article delineates a novel Pawar and Singh molar pulp chamber floor classification© for the anatomy of maxillary and mandibular molars to ease the clinician's skills and further increase the prevailing literature for the benefit of researchers.

Application of a new system for classifying root and canal anatomy in studies involving micro-computed tomography and cone beam computed tomography: Explanation and elaboration

Adequate knowledge and accurate characterization of root and canal anatomy is an essential prerequisite for successful root canal treatment and endodontic surgery. Over the years, an ever-increasing body of knowledge related to root and canal anatomy of the human dentition has accumulated. To correct deficiencies in existing systems, a new coding system for classifying root and canal morphology, accessory canals and anomalies has been introduced. In recent years, micro-computed tomography (micro-CT) and cone beam computed tomography (CBCT) have been used extensively to study the details of root and canal anatomy in extracted teeth and within clinical settings. This review aims to discuss the application of the new coding system in studies using micro-CT and CBCT, provide a detailed guide for appropriate characterization of root and canal anatomy and to discuss several controversial issues that may appear as potential limitations for proper characterization of roots and canals.

Evaluation of root morphology of maxillary and mandibular second molars lost due to periodontitis

BACKGROUND AND OBJECTIVE

Little is known about the anatomical characteristics of root morphology in molars lost due to periodontal reason. The aim of this study was to study root morphology in maxillary and mandibular molars lost due to periodontitis by investigating the frequency of root fusion, classifying fusion types, and measuring radicular groove depth by micro-computed tomography.

MATERIAL AND METHODS

Ninety-eight posterior teeth were collected from 87 Japanese patients during the study period. Of these, maxillary (N = 36) and mandibular (N = 22) second molars lost most frequently were assessed for root fusion and morphology.

RESULTS

The 36 maxillary second molars included nine (25%) teeth with a single root, 14 (39%) with two roots, and 13 (36%) with three roots. Of the 23 maxillary second molars with fused (1 and 2) roots, there were 11 (48%), 2 (9%), 1 (4%), 1 (4%), 3 (13%), and 5 (22%) teeth with root types 1-6, respectively. The 22 mandibular second molars comprised 14 (64%) teeth with a single root, 7 (32%) with two roots, and one (4%) with three roots. Of the 14 mandibular second molars with a fused (1) root, 12 (86%) had a C-shaped root and two (14%) had a non-C-shaped root.

CONCLUSION

We observed a higher frequency of root fusion in the present study compared with that reported by previous studies using randomly selected second molars.

Analysis of root canal system of maxillary first and second molars and their correlations by cone beam computed tomography

BACKGROUND/PURPOSE

Understanding the root canal systems of molars and the association of root canal system in adjacent or contralateral molars is important for dental practice. This study aimed to use cone-beam computed tomography (CBCT) to analyze the morphology similarity of root canal systems in the maxillary first and second molars.

METHODS

CBCT images of 1741 maxillary molars in a total of 519 patients were blindly examined to analyze the correlation of root canal systems between maxillary first and second molars as well as the bilateral first and second molars.

RESULTS

The most common type in maxillary first molars is 3R4C (3 roots/4 canals), whereas in maxillary second molars is 3R3C.The symmetry in type of root canals in bilateral maxillary first and second molars were 87.36% and 79.85%, respectively. The similarities of root canal system in adjacent maxillary first and second molars were 53.07% (right side) and 52.58% (left side). The concurrence of MB2 canal in bilateral maxillary first molars is 77.8%, and 35.97% in maxillary second molars. In the 110 patients with MB2 canal in bilateral maxillary second molars, the chance of bilateral MB2 canals in their maxillary first molar is almost 100%.

CONCLUSION

Maxillary first molars have higher prevalence of 3R4C than second molars. The symmetry in bilateral maxillary molars is higher than the similarity in adjacent maxillary first and second molars. Application of CBCT analysis of root canal system can improve endodontic treatment outcomes. The correlation of root canal system between teeth is useful for genetic linkage.

Fused roots of maxillary molars: characterization and prevalence in a Latin American sub-population: a cone beam computed tomography study

Objectives

The upper molars generally have three roots; therefore, different combinations of fusion can occur, increasing the possibility of finding more complex root canal systems. The purpose of this study was to evaluate the prevalence and characterization of fused roots in first and second maxillary molars using cone-beam computed tomography (CBCT) in a Colombian population.

Materials and Methods

A total of 1274 teeth were evaluated, of which 534 were maxillary first molars and 740 were maxillary second molars. Axial sections were made at the cervical, middle, and apical levels to determine the prevalence of root fusion and the types of fusion.

Results

Overall, 43% of the molars (n = 551) presented some type of fused root. Root fusion was present in 23.4% of the maxillary first molars. The most frequent type of fused root was type 3 (distobuccal-palatal; DB-P) (58.9%). Root fusion was observed in 57.6% of the maxillary second molars, and the most prevalent type of fused root was type 6 (cone-shaped) (45.2%). Of the maxillary molars, 12.5% were classified as C-shaped.

Conclusion

Within the limitations of this study, there was a high prevalence of fused roots in maxillary molars in the Colombian population, mainly in the maxillary second molars. In first molars, the most common type of fused root was type 3 (DB-P) and in second molars, the most common type was type 6 (cone-shaped). Additionally, molars with root fusion presented variation at different levels of the radicular portion, with implications for treatment quality.

A radiographic study estimating age of mandibular third molars by periodontal ligament visibility

BACKGROUND

Visibility of the periodontal ligament of mandibular third molars (M3) has been suggested as a method to estimate age.

AIM

To assess the accuracy of this method and compare the visibility of the periodontal ligament in the left M3 with the right M3. The sample was archived panoramic dental radiographs of 163 individuals (75 males, 88 females, age 16-53 years) with mature M3's.

MATERIALS AND METHODS

Reliability was assessed using Kappa. Accuracy was assessed by subtracting chronological age from estimated age for males and females. Stages were cross-tabulated against age stages younger than and at least 18 and 21 years of age. Stages were compared in the left M3 and right M3.

RESULTS

Analysis showed excellent intra-observer reliability. Mean difference between estimated and chronological ages was 7.21 years (SD 5.16) for left M3 and 7.69 (SD 6.08) for right M3 in males and 6.87 (SD 5.83) for left M3 and 8.61 (SD 6.58) for right M3 in females. Minimum ages of stages 0 to 2 were younger than previously reported, despite a small sample of individuals younger than 18. The left and right M3 stage differed in 46% of the 85 individuals with readings from both side and estimated age differed from -10.5 to 12.2 years between left and right.

CONCLUSION

Accuracy of this method was between 6 and 8 years with an error of 5 to 6 years. The number of individuals with mature M3 apices younger than 18 years was small. The stage of visibility of the periodontal ligament differed between left and right in almost half of our sample with both teeth present. Our findings question the use of this method to estimate age or to discriminate between age younger and at least 18 years.

Root Canal Morphology of Permanent Mandibular Premolars in Iranian Population: A Systematic Review

INTRODUCTION

It is essential for clinicians to have knowledge about root canal configuration, although its morphology varies largely in different ethnicities and even in different individuals within the same ethnic group. The current study reviewed the root canal configuration of root canals in mandibular first and second premolars among Iranian population based on independent epidemiological studies.

METHODS AND MATERIALS

A comprehensive search was conducted on retrieved articles related to root canal configuration and prevalence of each types of root canal in mandibular premolars based on Vertucci's classification. An electronic search was conducted in Medline, Scopus and Google Scholar from January 1984 to September 2015.

RESULTS

In eleven studies conducted in eight provinces, 1644 mandibular first premolars and 1268 second premolars were investigated. Within mandibular first premolars, 70.9% were Vertucci's type I, followed by 10.4% type III, 7.18% type IV, 5.23% type II and 5.16% type V. In addition, among mandibular second premolars, 82.86% were type I, 6.25 type III, 5.32% type II, 4.27% type IV, and 0.69% type V.

CONCLUSION

These results highlight the necessity of searching for additional possible root canals by clinicians. Moreover, these results indicated the ethnical characteristics of Iranian population regarding the morphology of mandibular premolars compared to other populations.

Analysis of C-shaped root canal configuration in maxillary molars in a Korean population using cone-beam computed tomography

OBJECTIVES

The purpose of this study was to investigate the incidence of root fusion and C-shaped root canals in maxillary molars, and to classify the types of C-shaped canal by analyzing cone-beam computed tomography (CBCT) in a Korean population.

MATERIALS AND METHODS

Digitized CBCT images from 911 subjects were obtained in Chosun University Dental Hospital between February 2010 and July 2012 for orthodontic treatment. Among them, a total of selected 3,553 data of maxillary molars were analyzed retrospectively. Tomography sections in the axial, coronal, and sagittal planes were displayed by PiViewstar and Rapidia MPR software (Infinitt Co.). The incidence and types of root fusion and C-shaped root canals were evaluated and the incidence between the first and the second molar was compared using Chi-square test.

RESULTS

Root fusion was present in 3.2% of the first molars and 19.5% of the second molars, and fusion of mesiobuccal and palatal root was dominant. C-shaped root canals were present in 0.8% of the first molars and 2.7% of the second molars. The frequency of root fusion and C-shaped canal was significantly higher in the second molar than the first molar (p < 0.001).

CONCLUSIONS

In a Korean population, maxillary molars showed total 11.3% of root fusion and 1.8% of C-shaped root canals. Furthermore, root fusion and C-shaped root canals were seen more frequently in the maxillary second molars.

Evaluation of the Root and Canal Morphology of Maxillary Permanent Molars and the Incidence of the Second Mesiobuccal Root Canal in Greek Population Using Cone-beam Computed Tomography

Objectives: Cone-Beam Computed Tomography is an alternative imaging technique which has been recently introduced in the field of Oral &amp; Maxillofacial Radiology. It has rapidly gained great popularity among clinicians due to its ability to detect lesions and defects of the orofacial region and provide three-dimensional information about them. In the field of Endodontics, CBCT can be a useful tool to reveal tooth morphology irregularities, additional root canals and vertical root fractures. The objective of this study is to evaluate the root and root canal morphology of the maxillary permanent molars in Greek population using Cone-Beam Computed Tomography. Materials and Methods : 273 cone-beam computed tomography (CBCT) images were examined. The number of roots and root canals of the first and second maxillary molars were evaluated. Root canal configuration was classified according to Weine’s classification by two independent examiners and statistical analysis was performed. Results : A total of 812 molars (410 first and 402 second ones) were evaluated. The vast majority of both first and second molars had three roots (89.26% and 85.07%, respectively). Most first molars had four canals, while most second molars had three. In the mesiobuccal roots, one foramen was recorded in 80.91% of all teeth. Other rare morphologic variations were also found, such as fusion of a maxillary second molar with a supernumerary tooth. Conclusion : Within the limitations of this study, it can be concluded that more attention should be given to the detection of additional canals during root canal treatment in maxillary permanent molars. Towards this effort, CBCT can provide the clinician with supplemental information about the different root canal configurations for successful Root Canal Treatment.

Gender difference and root canal morphology in mandibular premolars: A cone-beam computed tomography study in an Iranian population

BACKGROUND

Mandibular premolars are of the most difficult teeth to treat endodontically.

AIMS

To compare the root canal morphology of mandibular premolars between two genders in an Iranian population.

SETTINGS AND DESIGN

Totally, 230 cone-beam computed tomography images of the mandibles belonged to 115 males and 115 females were evaluated in the three spatial planes.

MATERIALS AND METHODS

The total number of roots and canals in the mandibular premolars was counted, and the difference between males and females were analyzed.

STATISTICAL ANALYSIS

Data were analyzed using Chi-square test. The significance level was set as P < 0.05.

RESULTS

The majority of mandibular first and second premolars had one root (85.7% and 94.8%, respectively) and one canal (63.9% and 78.3%, respectively). The number of roots in the mandibular first premolars had statistically significant difference between two genders (P = 0.001). There was no significant difference between two genders in the number of roots (P = 0.208) and canals (P = 0.498) in the mandibular second premolars.

CONCLUSION

According to the results of this study, the root canal morphology in the mandibular first premolars had statistically significant difference between two genders.

Endodontic management of an unusual maxillary first molar with a single buccal root

AIM

The aim of this clinical article is to describe the unusual anatomy that was detected in a maxillary first molar during routine endodontic treatment.

BACKGROUND

Variation in Root and Root canal morphology especially in multirooted teeth presents a constant challenge for a clinician in their detection and management. The literature is replete with cases that have extra canal or Root but cases with fused Root and fewer numbers of canals are sparse.

CASE DESCRIPTION

This case report describes the endodontic management of one such unusual case of maxillary first molar presenting with a single fused buccal and a palatal Root. The confirmatory diagnosis of this morphologic aberration was done with the help of spiral computerized tomography, which revealed that the contralateral tooth also had a similar morphology.

CONCLUSION

Dental practitioners should always be aware of the fact that abnormalities need not be in form of extra Roots or Root canals; anomalies can also be in form of fewer number of Roots or Root canals.

CLINICAL SIGNIFICANCE

A thorough knowledge of the complexities and variations of the Root canal system would help in avoiding some of the common iatrogenic access opening errors like perforations and excessive tooth removal caused during the search for the missing or extracanal.

Analysis of periodontal attachment loss in relation to root form abnormalities

Purpose

The aim of this study was to explore root shape abnormalities, to investigate the influence of root form abnormalities on periodontal attachment loss, and to gather basic data to assist in the diagnosis and treatment of aggressive periodontitis.

Methods

From January 2010 to June 2012, a survey was conducted of all 3,284 periodontitis patients who visited the Department of Periodontology, Daejeon Dental Hospital, Wonkwang University School of Dentistry. Clinical parameters (probing depth, periodontal attachment loss, missing teeth) were measured and a radiographic examination was performed at the baseline. We classified the root shape abnormality of bicuspids and molars based on Meng classification.

Results

The periodontal attachment loss was the highest at the maxillary first molar (6.03 mm). The loss of the second molar was prominent. Type V deformity was shown to be the most common in the second maxillary and mandibular molars (P<0.05). Type V root shape was associated with the highest attachment loss (P=0.01).

Conclusions

Considering the small population and limited design of this study, definitive conclusions cannot be drawn. We suggest larger scale, methodologically more sophisticated studies that include normal controls and chronic periodontitis patients to clarify whether root form abnormalities are a potential risk factor for aggressive periodontitis.

Root and canal morphology of maxillary first and second permanent molar teeth in a Ugandan population

AIM

To investigate the root and canal morphology of permanent maxillary molar teeth from a Ugandan population.

METHODOLOGY

Maxillary first (n = 221) and second molar (n = 221) teeth were collected from patients attending dental clinics in Kampala. Teeth were prepared using a clearing technique: the pulp chambers were accessed and the teeth placed consecutively into 5% sodium hypochlorite, 10% nitric acid, then methyl salicylate. Indian ink was injected into the pulp chambers to demonstrate the canal system.

RESULTS

In the first molars, 95.9% of the teeth had separate roots. The mesiobuccal root was fused with the palatal root in 3% of specimens and with the distobuccal root in 0.5% of teeth. In the second molars, 86% of the teeth had separate roots. The mesiobuccal root was fused with the palatal root in 6.3% of specimens and with the distobuccal root in 6.8% of teeth. Apical deltas were more frequent in the mesiobuccal root when compared with distobuccal and palatal roots of both the first and second molars. A type I canal configuration (>75%) was the most frequent in all the roots of both the first and second molars. Canal intercommunications and lateral canals were more frequent in the mesiobuccal root when compared with other roots.

CONCLUSIONS

The mesiobuccal root tended to have more variations in the canal system followed by the distobuccal root, whereas the palatal root had the least. The findings in root and canal morphology of this Ugandan population were different from previous studies, which may partly be attributed to racial differences.

The Root and Root Canal Morphology of the Human Mandibular First Premolar: A Literature Review

The purpose of this study was to undertake a comprehensive literature review of the root and root canal morphology of the mandibular first premolar. Published studies citing the anatomy and morphology of mandibular premolars report data for over 6,700 teeth. These studies were divided into anatomical studies reporting number of roots, number of canals, and apical morphology. Variations because of sex and ethnic background have also been reported, along with case reports of anomalies. Approximately 98% of the teeth in these studies were single-rooted. The incidence of two roots was 1.8%. Three roots when reported were found in 0.2% of the teeth studied. Four roots were rare and were found in less than 0.1% of the teeth studied. Studies of the internal canal morphology revealed that a single canal was present in 75.8% of the teeth. Two or more canals were found in 24.2% of the teeth studied. A single apical foramen was found in 78.9% of the teeth, whereas 21.1% had two or more apical foramina. The role of genetics and racial variation may result in differences of incidence of root number and canal number in human populations. The dental literature is not unique in studying ethnicity and sex variations. Higher incidences of teeth with additional canals and roots have been reported in Chinese, Australian, and sub-Sahara African populations. Physical anthropology studies seem to show the lowest incidence in Western Eurasian, Japanese and American Arctic populations. The root and root canal morphology of this tooth can be complex and requires careful evaluation prior to root canal therapy.

Canal configuration in the mesio-buccal root of maxillary first molar teeth of a Jordanian population

The purpose of this study was to investigate the canal configuration in the mesio-buccal root of maxillary first molar teeth of a Jordanian population using a clearing technique. One hundred extracted maxillary first molars were collected from Jordanian patients. After a standard access preparation, canals were stained, decalcified, dehydrated, and then rendered clear. The prevalence of a second canal in the mesio-buccal root was 77.32%. Types IV and II canal systems were the most common types with prevalence of 35.05% and 27.83%, respectively. Additionally, 28.86% showed lateral canals mostly located in the apical third and 37.11% had intercanal communications, mainly in the middle third of the root. It was concluded that the prevalence of mesio-palatal canals was high and Types IV and II canal systems were the most prevalent.

Mesial Migration Effect on Root Morphology of Mandibular Third Molars

Objective: To test the hypothesis that there is a relationship between forward mandibular third molar migration and root curvature of the mandibular third molars.

Materials and Methods: The study is comprised of 64 patients who had a history of unilateral mandibular first molar extraction before 16 years of age with no other missing teeth or prosthetic restorations in the mandible. The extraction space was fully or partly closed. The mean remaining space was 1.1 ± 0.41 mm. The root angles for the mesial and distal roots of the mandibular third molars were measured on the panoramic radiographs by calculating the differences between the angle formed by the long axis drawn perpendicular to the occlusal plane of the crown of mandibular third molar and the central line of the lower one ninth of the root through the root apex. The differences between the extracted and nonextracted sides for mesial and distal roots were analyzed using a paired sample t-test.

Results: Both mesial and distal roots were approximately 8° more vertical on the extraction sides than on the nonextraction sides. The differences were statistically significant.

Conclusion: Mesial tooth migration of mandibular third molars reduces the amount of root curvature developing on this tooth.

Root and root canal morphology of the human permanent maxillary first molar: a literature review

The objective of this study was to review the literature with respect to the root and canal systems in the maxillary first molar. Root anatomy studies were divided into laboratory studies (in vitro), clinical root canal system anatomy studies (in vivo) and clinical case reports of anomalies. Over 95% (95.9%) of maxillary first molars had three roots and 3.9% had two roots. The incidence of fusion of any two or three roots was approximately 5.2%. Conical and C-shaped roots and canals were rarely found (0.12%). This review contained the most data on the canal morphology of the mesiobuccal root with a total of 8399 teeth from 34 studies. The incidence of two canals in the mesiobuccal root was 56.8% and of one canal was 43.1% in a weighted average of all reported studies. The incidence of two canals in the mesiobuccal root was higher in laboratory studies (60.5%) compared to clinical studies (54.7%). Less variation was found in the distobuccal and palatal roots and the results were reported from fourteen studies consisting of 2576 teeth. One canal was found in the distobuccal root in 98.3% of teeth whereas the palatal root had one canal in over 99% of the teeth studied.

Radiographic alveolar bone loss in untreated Taiwan Chinese subjects with adult periodontitis measured by the digital scanning radiographic image analysis method

OBJECTIVES

To determine differences in radiographic alveolar bone loss (RABL) by age group, gender and tooth type in subjects with adult periodontitis using the digital scanning radiographic image analysis (DSRIA) method.

METHODS

A total of 4262 teeth were examined for RABL in 178 individuals (96 males and 82 females). Mesial and distal sites were determined by the DSRIA method following scanning of periapical radiographs and using the Microstation 95 image software.

RESULTS

Linear assessment of RABL using DSRIA revealed the following results. Mean bone loss of maxillary and mandibular anterior teeth was significantly higher (P<0.001 and P<0.01, respectively) in males compared with females using a two-sample t-test. The highest values of mean RABL occurred most commonly in the maxillary first molars (53.8% and 51.4% for females and males, respectively) and the mandibular central incisors (50.4% and 41.5% for males and females, respectively). Mean RABL was greater in males than in females for both the mandibular and maxillary arches, with the exception of molar sites.

CONCLUSIONS

Maxillary first molars and mandibular incisors are the highest risk sites. Moreover, greater loss occurs at the molar site in females compared with males for untreated periodontitis in Taiwan Chinese people.

Root and canal morphology of Thai maxillary molars

AIM

To investigate the root and canal morphology of 268 maxillary permanent molars collected from an indigenous Thai population.

METHODOLOGY

The cleaned teeth were accessed, the pulp dissolved by sodium hypochlorite under ultrasonication, and the pulp system injected with Indian ink. The teeth were rendered clear by demineralization and immersion in methyl salicylate. The following observations were made: (i) number of roots and their morphology; (ii) number of root canals per root; (iii) root-canal configuration in each root using Vertucci's classification with additional modifications; and (iv) presence and location of lateral canals and intercanal communications.

RESULTS

All the maxillary first and second molars had three separate roots. Only, half (51%) of the maxillary third molars had three separate roots; the other half had fused or conical roots. The majority of the distobuccal (98.1-100%) and palatal (100%) roots had type I canals. Over half of the mesiobuccal roots of first (65%) and second (55%) molars had two canals. The most common (44.2%) canal configuration in mesiobuccal roots of first molars was type IV (two canals, two foramina). A variety of canal types were found in the mesiobuccal roots of second molars. Maxillary third molars showed the greatest diversity of canal morphology. There was an increase in the prevalence of lateral canals towards the apical part of the roots and intercanal communications were present in 16% of each of first, second and third Thai maxillary molars.

CONCLUSIONS

The mesiobuccal roots of Thai maxillary molars possessed a variety of canal system types. Over 50% of the first molars had a second mesiobuccal canal. The palatal and distobuccal canals mainly had type I canals. Only, a small proportion (7.3-13.3%) of the roots exhibited lateral canals which were the most common in the apical third

Root and canal morphology of Burmese maxillary molars

AIM

To investigate the root and canal morphology of Burmese maxillary molars using a canal staining and tooth clearing technique.

METHODOLOGY

Maxillary molars (239) were collected from indigenous Burmese patients and designated; first (90), second (77), third (72) molars. Following pulp tissue removal and canal system staining with Indian ink, the teeth were decalcified with 10% nitric acid, dehydrated and cleared with methyl salicylate. The following features were evaluated: (i) number of roots and morphology; (ii) number of canals per root: (iii) root canal configuration (Vertucci's classification); (iv) number of apical foramina per root; (v) number and location of lateral canals; and (vi) the presence of intercanal communications.

RESULTS

All first and second molars had three separate roots, whilst third molars had one of five different root forms, of which three separate (25%) or fused (31%) roots were most prevalent. The majority of palatal (100%) and disto-buccal (96%) roots possessed one canal (type I). The prevalence of mesio-buccal roots with two canals decreased from first to third molars (68%, 49%, 39%, respectively); type II (two orifices, one apical foramen) and IV (two orifices, two apical foramina) configurations were the most common. Single/fused rooted third molars had a range of number and type of canals. Most roots in all molars had one apical foramen, those with four apical foramina were confined to third molars. Intercanal communications were most prevalent in mesio-buccal roots and two/three fused rooted third molars. Lateral canals were most prevalent in the apical third of the roots of all molars.

CONCLUSIONS

The mesio-buccal roots of Burmese maxillary molars possessed a variety of canal system types. Over 50% of the first and second molars had a second mesio-buccal canal, of which over 20% had intercanal communications. The palatal and disto-buccal canals mainly had type I canals. Lateral canals were equally prevalent in all tooth types but were most common in the apical third.

Relationship of third molar development and root angulation

Angled roots are seen in mandibular third molars, which have a high frequency of incomplete impaction. We examined the relationship between incomplete impaction and angled roots. We enrolled orthopantomographs to determine the prevalence of angled roots in 239 men and 222 women aged 21--35 years with bilateral mandibular third molars. Angled roots were more frequent in subjects in whom the third molars had a different status on each side than in those with the same status on both sides (men: P<0.05; women: P<0.01). The incidence of women with angled roots in those with bilateral incomplete impactions was higher than that in those with bilateral eruption (P<0.01). Angled roots among mandibular third molars are related to environmental factors. Angled roots occur more frequently in women with incomplete impaction than in those with full eruption.

Relationship between molar root fusion and localized periodontitis

We investigated the relationship between molar root fusion and localized periodontitis in this study. A total of 143 individuals (1,109 molars) aged 23 to 68 years were examined for the presence of molar root fusion at diseased and healthy sites. Molar root fusions were diagnosed by periapical radiographs and clinical probing. Periodontal parameters measured included probing depth (PD), clinical attachment loss (CAL), gingival index (GI), and plaque index (PLI) around fused molars. Results indicated that the prevalence of molar root fusions in males and females was 15.2% (93/612) and 32.2% (160/497), respectively. The distribution of molars with root fusions occurs in the following order: maxillary second molars (51.8%), mandibular second molars (32.3%), maxillary first molars (5.7%), and mandibular first molars (0%). Statistically significant differences were observed between molar root fusions at healthy and diseased sites with respect to PLI, GI, PD, and CAL. The highest prevalence of molar root fusion was observed in females.

Types and dimensions of root trunk correlating with diagnosis of molar furcation involvements

The objective of the present study was to investigate the possible correlation of dimension, location, prevalence, and types of root trunk with molar furcation involvement (FI). The samples used in the study include 166 maxillary molars (70 1st and 96 2nd molars) and 200 mandibular molars (103 1st and 97 2nd molars). The dimensions of the root trunks and root lengths were measured with an electric caliper and their means and standard deviations calculated. The types of root trunks were identified by the ratio of root trunk dimension to root length and classified as types A, B, and C. The results may be summarized as follows. (1) Short-root trunks were more commonly found buccally, whereas long-root trunks were more commonly found mesially, in both maxillary molars. (2) Short-root trunks were most commonly found buccally, whereas long-root trunks were more commonly found lingually in both mandibular molars. (3) Long-root trunks were more commonly found on the 2nd molars than on the 1st molars. (4) Long-root trunks were associated with short root length. (5) There is a strong correlation between vertical length and type of root trunk and FI. The findings of the study indicated that an awareness of root trunk type together with horizontal and vertical attachment levels in molar FI may be helpful in the prognosis, diagnosis, and treatment of molar FI.

The maxillary second molar: variations in the number of roots and canals

A retrospective study was undertaken of 520 completed endodontic treatments of maxillary second molar teeth which were selected from a specialty endodontic practice. Radiographs were reviewed and studied, a classification of antomical root and canal variations was devised, and the frequency with which each variant occurred was recorded. There were six variants which occurred frequently enough to be considered as separate anatomic categories and their frequency of occurrence is illustrated. The six variants found in the study and their frequency of occurrence are as follows: (1) three separate roots and three separate canals (56.9%); (2) three separate roots and four canals (two in the mesiobuccal root) (22.7%); (3) three roots and canals whose mesiobuccal and distobuccal canals combine to form a common buccal with a separate palatal (9%); (4) two separate roots with a single canal in each (6.9%); (5) one main root and canal (3.1%); and (6) four separate roots and four separate canals including two palatal (1.4%). Clinical examples of these deviant variations are also presented.

Pyramidal molar roots and canine-like dental morphologic features in multiple family members: a case report

We report on three cases of unusual dental morphologic characteristics with pyramidal-shaped premolars and fused molar roots occurring in two generations. The dental abnormalities were hereditary in nature with morphologic features similar to those described by others. The features described in the literature were inherited in a pattern suggestive of a polygenic system with incomplete penetrance, although autosomal dominant inheritance with variable expression was possible. The present cases are found in a fashion suggestive of an autosomal dominant inheritance pattern, but insufficient evidence is available to state this for certain. In this case report, we describe a family with the previously stated anomalies and discuss potential causes for their condition as well as their clinical relevance.

The morphology of root fusion in Chinese adults (I). Grades, types, location and distribution

The purpose of the present study was to investigate the morphology, extent, and distribution of root fusions in 1st and 2nd permanent molars in a Chinese population. The sample consisted of 158 maxillary and 151 mandibular extracted 1st and 2nd molars. Root fusion in molars was assessed by direct viewing and measuring the length of the root and root trunk with stereoscopic microscopy. Root fusion was graded by the extent of fusion and the number of affected surfaces. The main results were as follows: (1) the majority of root fusions affected upper and lower 2nd molars (39.7% and 28.1%, respectively); (2) the prevalence of maxillary roots with 1, 2 and 3 fusions was 55.2%, 31.3% and 13.4% respectively, and most of the root fusions affected the maxillary 2nd molars (65.7%); (3) the majority of mandibular root fusions affected the 2nd molars (89.2%), and were of grade III (48.7%); (4) in order of decreased prevalence, the grades of root fusion in 2nd molars were grades III, II and I; whereas in 1st molars they were grades I, II and III; (5) there were 44 (41.5%) and 19 (51.4%) complete root fusions (grade III) among 106 fused roots in maxillary molars and 37 fused roots in mandibular molars, respectively.