Comparative evaluation of change in root canal shape and area in primary molars using ProTaper and K3 rotary systems In vitro study

Background: Rotary instrument techniques have shown evidence of simultaneously enlarging the root canal and maintaining the canal anatomy. Protocols for the use of rotary systems in primary molars are not well established. Aims: The aim of the study was to evaluate and compare root canal shape and area after ProTaper and K3 rotary instrumentation in primary molars. Settings and Design: Coronal access cavities with straight-line access into the root canals were prepared on primary mandibular molar teeth, extracted for therapeutic reasons. The teeth were aligned in a prefabricated template in individual self-cure acrylic blocks such that their respective positions could be reproduced later. Subject and Methods: Forty-two primary mandibular molar teeth selected were equally divided into three groups: instruments with stainless-steel (SS) hand K-files, ProTaper, and K3 Endo rotary system. Precomputed tomography (CT) slices were taken at predetermined levels (coronal, middle, and apical third) followed by instrumentation of canals using selected files and post-CT scan. Statistical Analysis Used: Data obtained were evaluated using independent t-test with a 0.05 level of significance and ANOVA. Results: SS hand K-files and rotary ProTaper and K3 Endo of 0.04 taper produced a predominantly round shape at coronal, middle, and apical levels. ProTaper system caused the greatest increase in round-shaped canals and canal area followed by K3 Endo of 0.04 taper. Conclusions: Shaping abilities of both manual and rotary instrumentation systems in primary molars were similar, whereas for enlarging and maintaining anatomy, rotary systems (ProTaper and K3) were better.

Prevalence of Middle Mesial Canal Based on Clinical and Radiological Evaluation in Permanent Mandibular First Molar: A Clinical and Cone-beam Computed Tomography Analysis

Background: The success of endodontic therapy depends on the complete debridement of the entire root canal system. Manystudies have investigated the morphology of mandibular molar, but the prevalence of the middle mesial canal in the mesialroot of the mandibular first molar is still the subject of controversy. Missed canal and consequently inadequate debridement ofthe root canal system can eventually lead to failure of therapy. Hence, it is imperative to meticulously look for extra canals toensure successful treatment.Materials and Methods: In this in vivo study, 100 patients who reported for root canal treatment were included in the study.Patients’ age and sex were recorded. After access cavity preparation, a standardized technique is performed between themesiobuccal canal and mesiolingual canal to search for a middle mesial canal using a dental operating microscope and confirmedradiologically by taking cone-beam computed tomographic image and results were analyzed.Results: In our study, out of 100 patients included that 50 patients were male and 50 patients were female. Based on gender,the prevalence of middle mesial canal in tooth number 36 and 46 is 18% (9 patients) and 19% (10 patients); for females andmales, it is 20% (10 patients) and 22% (11 patients). Based on age group, the prevalence of middle mesial canal in tooth number36 and 46 between the age of 15 and 30 is 23% (13 patients) and 24% (15 patients), between the age of 31 and 60 is 20%(5 patients) and 22% (6 patients), and age above 60 is 14% (1 patient) and 16% (2 patients), respectively.Conclusion: From this study, we concluded that the prevalence of the middle mesial canal in the permanent mandibular firstmolar can be as high as 24%, with the prevalence being higher in males than females and the age group between 15 and30 years had the highest prevalence.

A Cone-Beam Computed Tomography Study on the Morphometry of the Mandibular Molars and Their Relative Root Lengths to the Mandibular Height

@#The first, second and third mandibular molars (M1, M2, M3) show variations in the number of cusps and some distinction in size, occlusal design, and the relative lengths and number of roots. However, there are also genetic and racial related variations within them. This study determined the tooth length and related root-to-crown ratio (RCR), and root morphology variations in M1 and M2. We also determined the root length relative to the mandibular height of these teeth. Sixty-one conebeam computed tomography (CBCT) images of patients who had a good set of lower teeth with no sign of mandibular pathology or defect were included. Relevant measurements were made along the axes of the mesial and distal roots of these mandibular molars. The measurements obtained were used to calculate RCR and root-to-mandible (R/M) ratio. The crowns of 226 teeth and 465 roots were reviewed in 61 CBCTs of Malay patients. M1 and M2 were 19.41 mm and 18.15 mm long. The respective anatomical RCR and clinical RCR were 1.90 and 1.59 for M1, and 1.86 and 1.60 for M2. Thirteen molars (5.8%) presented with three roots, with twice the number affecting M1 than M2. More M1 (4.3%) had C-shaped morphology than M2 (1.8%). The R/M ratio at M1 was 42.32% and, at M2 this was 43.94 %. In summary, the morphometric measurements of M1 and M2 in Malay were established. These teeth did not have a high prevalence of supernumerary roots, but there is a high prevalence of C-shaped morphology in M1.

Radix entomolaris: reporte de caso / Radix entomolaris: report of a case

Una de las variaciones anatómicas que pueden presentar los molares inferiores es una tercera raíz que ha sido denominada radix entomolaris o paramolaris dependiendo de su localización, ya sea lingual o vestibular respectivamente. Conocer las variaciones morfológicas de las piezas dentarias es un requisito fundamental para el éxito del tratamiento endodóntico. El objetivo de este artículo es la presentación de un caso clínico de una paciente con ambos primeros molares inferiores con presencia de radix entomolaris; en la pieza dentaria 4.6 se realizó tratamiento endodóntico y en 3.6 con una lesión endoperiodontal combinada verdadera se decidió su exodoncia (AU)

Effects of continuous force application for extrusive tipping movement on periapical root resorption in the rat mandibular first molar / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to clarify the effects of continuous force application for extrusive tipping movement and occlusal interference on periapical root resorption in the rat mandibular first molar. METHODS: We constructed an appliance comprising a titanium screw implant with a cobalt-chromium post as the anchorage unit and a nickel-titanium closed coil spring (50 cN) as the active unit. Force was applied on the mandibular left first molar of rats for 8 (n = 10) and 15 days (n = 10; experimental groups), with the tooth in occlusion. Five rats were included as a non-treated control group to examine the body effect of the appliance. Active root resorption lacunae, identified using tartrate-resistant acid phosphatase, were evaluated in terms of the length, depth, and area. RESULTS: The rat mandibular first molars were mesially tipped and extruded in the occlusal direction. This mesio-occlusal tipping movement and occlusion resulted in the formation of a compression zone and active root resorption lacunae in the distoapical third of the distal roots. However, there was no significant difference in the amount of root resorption between the two experimental groups. The control group did not exhibit any active root resorption lacunae. CONCLUSIONS: Periapical root resorption was induced by continuous extrusive tipping force and occlusal interference in rat mandibular molars. These data suggest that we orthodontists had better take care not to induce occlusal interference during our orthodontic treatment.

Establishment of first mandibular molar development of the time sequence in ICR mice / 中国比较医学杂志

Objective This study aims to understand the characteristics of the time sequence of ICR mouse first mandibular molar tooth germ development through dynamic observation.Methods Tooth germ of Embryos (E11.5,E12.5,E13.5,E14.5,E15.5,E16.5,E17.5 and E18.5) and postnatal (PN1,PN2) mice were obtained.The heads (E11.5-E15.5) and mandibles (E16.5-PN2) of mice were dissected,fixed and embedded for serial sections and HE staining.All the results were assessed under light microscopy.Results The tooth germ underwent various development stages including the bud,cap and bell stages.Mouse odontogenesis was initiated at E11.5.Proliferation of oral epithelium formed the bud stage at E13.5.Then the cap stage was observed at E14.5-E15.5 and the bell stage was appeared beginning from E16.5.The pre-dentin was observed at PN1,as well as the dentin at PN2.Conclusions Establishing the regular development pattern of the first mandibular molar of ICR mice will provide a reliable basis for the future use in the specific tooth germ developmental research.

Prevalence of impacted permanent mandibular second molars in South Indian population: A cross-sectional study.

Aims: The aim of this study is to retrospectively determine the prevalence of impacted second molars and associated dental and radiographic findings in South Indian population. Settings and Design: Cross-sectional design. Materials and Methods: Dental records of 4976 patients depending on the selection criteria from various dental clinics in South India were retrospectively analyzed in this study. All selected radiographs and records were examined by the two authors. The angle of impacted second molars was also recorded on panoramic radiographs. Data were tabulated and analyzed. Results: The prevalence of impacted second mandibular molars was found to be 0.16%. In seven cases, the impaction was unilateral with three on the left and four on the right, and in one case, it was bilateral. The prevalence was found to be more in females than males. The angle of impaction was found to range from 19° to 80°. Conclusions: Although the prevalence of impacted second molars is low, it is crucial to diagnose early for optimal treatment.

Proximity of the mandibular molar root apex from the buccal bone surface: a cone-beam computed tomographic study

OBJECTIVES: The purpose of this study was to evaluate the proximity of the mandibular molar apex to the buccal bone surface in order to provide anatomic information for apical surgery. MATERIALS AND METHODS: Cone-beam computed tomography (CBCT) images of 127 mandibular first molars and 153 mandibular second molars were analyzed from 160 patients' records. The distance was measured from the buccal bone surface to the root apex and the apical 3.0 mm on the cross-sectional view of CBCT. RESULTS: The second molar apex and apical 3 mm were located significantly deeper relative to the buccal bone surface compared with the first molar (p < 0.01). For the mandibular second molars, the distance from the buccal bone surface to the root apex was significantly shorter in patients over 70 years of age (p < 0.05). Furthermore, this distance was significantly shorter when the first molar was missing compared to nonmissing cases (p < 0.05). For the mandibular first molars, the distance to the distal root apex of one distal-rooted tooth was significantly greater than the distance to the disto-buccal root apex (p < 0.01). In mandibular second molar, the distance to the apex of C-shaped roots was significantly greater than the distance to the mesial root apex of non-C-shaped roots (p < 0.01). CONCLUSIONS: For apical surgery in mandibular molars, the distance from the buccal bone surface to the apex and apical 3 mm is significantly affected by the location, patient age, an adjacent missing anterior tooth, and root configuration.

Hemisection: Split To Benefit - A Case Report.

Infections of periodontal or endodontic origin may result in increased periodontal probing depths with attachment loss adjacent to the root surface, bleeding on probing, suppuration, swelling, tooth mobility, angular bone loss, and pain on percussion. These signs and symptoms may be caused by plaque-associated periodontitis which begins at the margin of the gingiva and proceeds apically or by endodontic infections that enter the periodontal ligament at the apical foramen or through lateral or accessory canals and proceed coronally. The loss of posterior molars as a result of periodontal or endodontic infection leads to migration of teeth, supra-eruption of opposing teeth, loss of supporting alveolar bone and a decrease in masticatory efficiency. The unrestorable teeth can be replaced by removable partial dentures or fixed partial dentures or the recent treatment modality, dental implants. This case report presents one treatment option available to save the molars affected by extensive periodontal lesions, and thereby prevent the undesirable consequences of tooth loss. Hemisection refers to the sectioning of a molar tooth with the removal of an unrestorable root which may be affected by periodontal or endodontic infection or carious lesion. Careful case selection is necessary for long-term success.

Rare Patterns of Impacted Mandibular Teeth: A Case Series.

Tooth eruption is the axial movement of the tooth from its developmental position within the jaws to the functional position in the occlusion plane. Any interference in the complex sequential events or pathology of the surrounding bone may cause diffi culty in eruption. Th is may cause an ectopic eruption and aberrant eruption pattern. Th is process might be altered by genetic, molecular, cellular or tissue causes too. Impacted teeth may therefore, be non-functional, abnormal or pathological. Moreover, ectopic eruption of second molars is rarely seen and infrequent. Here we report a case series of ectopic eruption of permanent mandibular molars with some rarest presentation.

Mandibular Molar Protraction with Orthodontic Temporary Anchorage Devices: A Case Report.

Management of patients with congenitally missing mandibular second premolars continues to challenge clinicians to find the best treatment options. The Orthodontist must make the proper decision at the appropriate time regarding management of the edentulous space. If space is left for an eventual prosthetic replacement, the clinician should try to create the exact amount of space required and leave the alveolar ridge in an ideal condition for the future restoration. If the space is to be closed orthodontically, detrimental changes to the occlusion and facial profile must be prevented. Therefore, the correct decision must be made at the appropriate time. This paper presents a case report of a congenitally missing lower left second premolar where molar protraction with orthodontic temporary anchorage device has been done.

The Radix Entomolaris : A Rare Entity In Endodontics.

Mandibular molars can have an additional root located lingually (the radix entomolaris) or buccally (the radix paramolaris). If present, an awareness and understanding of this unusual root and its root canal morphology can contribute to the successful outcome of root canal treatment. This report discusses endodontic treatment of one Mandibular molar with a radix entomolaris or paramolaris, both of which are rare macrostructures in the Caucasian population. The prevalence, the external morphological variations and internal anatomy of the radix entomolaris and paramolaris are described. Avoiding procedural errors during endodontic therapy demand an adapted clinical approach to diagnosis and root canal treatment.

Variations in the Cusps of Mandibular Molars in Koreans / 체질인류학회지

This study aimed to investigate the cusp size and morphological characteristics of permanent mandibular molars in Koreans with reference to the hypoconulid, and to analyze the differences and correlations between both sexes as well as between first and second mandibular molars. We obtained data from dental casts of 110 adults (78 males and 32 females). Mesiodistal and buccolingual diameters of first and second mandibular molars, the area of five cusps (protoconid, metaconid, hypoconid, entoconid, and hypoconulid), as well as the total cusp area and occlusal table area were measured. Paired t-test was performed to analyze the morphological differences between first and second mandibular molars and the sex differences between both sexes using SPSS program. Crown diameters and cusp areas of mandibular first molars were larger than those of mandibular second molars in both sexes. The hypoconulid was the most variable in size and morphological pattern among the five cusps, and the first molars showed a higher incidence of hypoconulid than the second molars. Except for the entoconid area of the first molar (p=0.06) and the hypoconulid area of the second molar (p=0.24), all other mean values were larger in males than in females, demonstrating a significant sexual dimorphism. These data suggest that the teeth which develop late in ontogeny tend to be smaller in size and more variable in morphological characteristics.

Bicuspidised Molar as a Potential Prosthetic Abutment- A Case Report

Conservative management of periodontally compromised teeth with advanced furcation defects has proved to be challenging to the periodontists since ages. With the evolution of implant-based oral rehabilitation of edentulism, the ideology of preservation of the natural dentition is slowly fading. This case report aims at highlighting the conservative management of a grade III furcation-involved molar by bicuspidisation procedure and use of the treated tooth as an abutment for fixed prosthesis. Bicuspidisation is a surgical procedure performed on the mandibular molars for the separation of the mesial and distal roots with their respective crown portions; this separation eliminates the existence of a furcation and facilitates effective oral hygiene practice. The use of bicuspidisation still remains to be one of the most viable traditional options for the management of a Glickman's classification grade III furcation defect in the mandibular molar teeth to facilitate reduction in periodontal infection, oral hygiene maintenance, preservation of natural tooth structure and having the potential to serve as abutments for a fixed partial denture. A bicuspidised multirooted tooth can successfully serve as a potential abutment.

Hemisection for the management of periodontically compromised mandibular molar (advanced grade-III furcation involvement).

Advances in dentistry, as well as the increased desire of patients to maintain their dentition, have lead to treatment of teeth that once would have been removed. The treatment, management and long-term retention of mandibular molar teeth exhibiting furcation involvement always have been a challenge, especially when the furcation involvement has progressed to a class III furcation. Hemi-section of the affected tooth helps preserve the tooth structure. This case report describes a simple procedure for hemisection in mandibular molar having advance grade III furcation involvement by vertical cut method and its subsequent restoration.

The study on success rate of single implant replacing the mandibular first and second molars / 대한치과보철학회지

PURPOSE: After the introduction of concept of osteointegration, dental implantology have been successful procedure in the dental field. Recently, it has shown successful results when used to restore single tooth missing. Considering the difference in bone quality of the mandible and maxilla, and the increased occlusal force in the posterior region, the success rates in each region may be different. In this study, success rates of single implants placed in the mandibular first and second molar areas were analyzed. MATERIALS AND METHODS: The subjects were patients (284 patients, 308 implants) who had been operated with single implant installation from 2002 to 2009 in seven dental clinics in Daegu city. One hundred sixty eight implants were placed in the mandibular 1st molar and 140 implants were placed in the mandibular 2nd molar. They were analyzed according to implant site, age, sex, length and diameter. RESULTS: The survival rates of single implant of this study were 97.6% in the mandibular 1st molar and 92.9% in the mandibular 2nd molar. In the mandibular 1st molar, 4 implants were failed. In the mandibular, 2nd molar, 10 implants were failed. CONCLUSION: The restoration of the mandibular 1st molar using single implant was found to be clinically acceptable treatment and showed higher survival rate than mandibular 2nd molar single implant. Single implant in mandibular 2nd molar needs careful consideration of poor bone quality, risk of overloading and anatomical structure of the mandible.

Bilateral three-rooted primary lower molars.

The dental literature contains a small number of reports of primary multi-rooted anomalies. Among these reports the majority are regarding three-rooted primary mandibular second molar anomalies. The presence of bilateral three-rooted primary mandibular first and second molars is uncommon. There have been no reports of three-rooted primary molars from India. Here, we present a case of an 8-year-old boy with bilateral three-rooted primary mandibular first and second molars.

Clinical Management Of Radix Entomolaris And Radix Paramolaris In Endodontics- Case Reports.

Treatment of mandibular molars have always kept the endodontist sharp and alert as it is one of the teeth that show variations in its external and internal morphology to the extreme. This reaches its epitome in the presence of an additional root located lingually (the radix entomolaris) or buccally (the radix paramolaris). When present an awareness and understanding of this unusual root and its root canal morphology contributes to the successful outcome of root canal treatment. This report discusses endodontic treatment of two mandibular molars with a radix entomolaris or paramolaris. The prevalence, the external morphological variations and internal anatomy of the radix entomolaris and paramolaris are described.

The Radix Entomolaris – An Endodontic Challenge : Case Reports.

Mandibular molars can have an additional root located lingually (the radix entomolaris) or buccally (the radix paramolaris). If present, an awareness and understanding of this unusual root and its root canal morphology can contribute to the successful outcome of root canal treatment. This report discusses endodontic treatment of three mandibular molars with a radix entomolaris. The prevalence, the external morphological variations and internal anatomy of the radix entomolaris and paramolaris are described.

Endodontic Management Of Radix Entomolaris - Two Case Reports.

A mandibular first molar with two distal roots is an interesting example of anatomic variation. This paper describes 2 case reports of mandibular first molar with three roots (one mesial and two distal) and four canals (two in mesial and one in each distobuccal and distolingual root). The canals were shaped with protaper rotary files and irrigated with 2.5% sodium hyochlorite and 0.2 %w/v of chlorhexidine gluconate and normal saline as the final irrigant. The prevalence, the external morphological variations and internal anatomy of the radix entomolaris and paramolaris are described.