Study of the incidence of radicular grooves in maxillary incisors.

The purpose of this investigation was to determine the incidence of radicular grooves in the upper incisors of 642 patients from the region of Ribeir?o Preto, SP, Brazil. Radicular grooves, present in 3.9% of the patients, were found mainly on the lingual surface of the maxillary lateral incisor (3.0%). The maxillary central incisors showed radicular grooves on both the buccal and lingual surfaces with an incidence of 0.9%. It was not possible to relate the incidence of these grooves with race (white and negro) or with sex.     

Bilateral maxillary fused primary incisors accompanied by succedaneous supernumerary teeth: report of a case

Summary. A rare case of fusion between maxillary primary central incisors and supplemental teeth occurring bilaterally, accompanied by succedaneous supernumerary teeth, is presented. The patient was an 8·5-year-old Japanese boy. Intraoral examination revealed fusion of left and right maxillary primary central incisors to supplemental teeth, which had labial and lingual grooves. The maxillary primary lateral incisors were present. Radiographs showed that the fused teeth had separate roots, pulp chambers and root canals. There were two impacted supernumerary teeth and eruption of the permanent maxillary central incisors was delayed. Treatment was performed and the fused primary teeth and the impacted supernumerary teeth were extracted. After 6 months observation, surgical exposure of the two crowns of the permanent maxillary central incisors was performed. The teeth began to erupt and have since been kept under observation.     

A study on the thickness of radicular dentine and cementum in anterior and premolar teeth

AIM: This study aimed to measure the thickness of radicular dentine and cementum in incisors, canines and premolars, and to develop geometric average models. METHODOLOGY: The roots of 220 extracted human teeth were sectioned in three horizontal parallel planes and measured using an optical microscope. For each cut surface buccal, lingual, mesial, and distal thickness of the root wall was measured. Mean values of the thickness at each location of each cut surface were calculated. The observed differences in thickness by tooth type, location, and section were compared by ANOVA and Student's t-test. RESULTS: Maxillary central incisors and maxillary canines had the greatest widths. In all teeth with a single root, the wall thickness were greater on the lingual side than the buccal side. Although differences between mesial and distal thicknesses were not statistically significant. CONCLUSIONS: Wall thickness varied greatly. The lingual surfaces of roots were larger. All roots had thin walls in the apical third.     

Morphometric study of length and grooves of maxillary lateral incisor roots

OBJECTIVE: Root grooves are considered a risk factor for periodontal disease. The purpose of this study was to measure the length of the root of maxillary lateral incisors (MLI), as well as the width and depth of the concavities of their proximal surfaces, and also to determine the prevalence of palato-gingival grooves. METHODS: the width and depth of root concavities, as well as root length were evaluated in 73 MLI. All teeth were measured using a digital contour measuring instrument for the root grooves and a caliper for evaluating root length. RESULTS: After statistical analysis (p<0.05) it was possible to confirm: the mean root length on its mesial surface was (15.47+/-1.72 mm), on its distal surface (14.99+/-1.70 mm), on its buccal surface (13.10+/-1.69 mm) and on its lingual surface (12.71+/-1.53 mm); concavities were present in 100% of the samples; concavities were found 2mm, coronally from the CEJ, at the CEJ, and apically up to 8mm; the concavities were wider than deeper; on the mesial surface, the greatest width was (1.05 mm) and the greatest depth was (0.06 mm) both at the CEJ; 5) on the distal surface the greatest width was (0.73 mm) at 6mm apically from the CEJ and the greatest depth was (0.003 mm); the palato-gingival groove was observed in 9.58% of the samples. CONCLUSIONS: The mesial surface of the maxillary lateral incisor is the longest. The root concavities on the proximal surfaces are present in 100%. One must get acquainted to the morphological variations of roots to enhance diagnosis and treatment.     

Distribution of developmental defects of tooth enamel by tooth-type in 11–12-year-old children in South Wales

The distribution of enamel developmental defects in 759 11-12-yr-old children from South Wales is described. Overall, 8% of maxillary teeth were affected compared to 3.6% of mandibular teeth. Most teeth were affected equally on right and left sides of the mouth except for maxillary lateral incisors, which had significantly more defects on the right (P less than 0.05) and maxillary first molars, which had significantly more defects on the left (P less than 0.025). Maxillary central incisors (18.7%) were affected by enamel defects most often followed by maxillary first molars (8.1%) and maxillary lateral incisors (7.2%). The ranking order of the teeth varied when the prevalence of the different types of defects was assessed. White demarcated opacities were seen most often in maxillary central incisors (10.8%), yellow demarcated opacities in maxillary first molars (1.8%), diffuse opacities in maxillary central incisors (6.6%) and hypoplasias in mandibular first premolars (1.5%). Defects of all types occurred most frequently on the buccal surfaces of the teeth. In premolar and molar teeth more defects occurred on the occlusal surface than on the lingual.     

上颌阻生尖牙牵引治疗后邻近切牙牙根吸收情况的研究

目的 分析上颌阻生尖牙正畸牵引治疗后邻近切牙的牙根吸收情况及可能的相关因素。方法 选取上颌尖牙阻生且符合标准的43例患者,年龄10～23岁,共60颗上颌埋伏阻生尖牙。上颌阻生尖牙正畸牵引治疗前后分别拍摄锥形束CT,分析阻生尖牙邻近切牙的牙根吸收程度,并对可能存在的相关因素进行分析。结果 上颌阻生尖牙正畸牵引治疗后,上颌中切牙发生轻、中、重度牙根吸收的概率分别为71.7%、15.0%、13.3%,上颌侧切牙发生轻、中、重度牙根吸收的概率分别为48.3%、36.7%、15.0%,上颌中切牙与侧切牙牙根吸收严重程度存在差异(P<0.05)。位于腭侧及颌骨内、低位且靠近面中线的阻生尖牙,在正畸牵引治疗后,侧切牙牙根吸收程度较重(P<0.05)。低位阻生尖牙牵引治疗后,中切牙牙根吸收较重(P<0.05)。牵引时间较长时,中切牙牙根吸收程度较重(P<0.05)。治疗前已发生牙根吸收的切牙,在阻生尖牙牵引治疗后发生的牙根吸收程度较重(P<0.05)。结论 上颌侧切牙在阻生尖牙正畸牵引治疗后,发生的牙根吸收程度较重。上颌阻生尖牙正畸牵引治疗后,邻近切牙牙根吸收情况与阻生尖...     

Endodontic-periodontal management of a maxillary lateral incisor with an associated radicular lingual groove and severe periapical osseous destruction--a case report

Radicular lingual grooves are morphological defects, which are found most frequently in maxillary anterior teeth and are a predisposing factor for periodontal disease. They are easily overlooked as aetiologic factors, as these grooves are covered by periodontal tissues. This case report presents a successful management of a case of a maxillary lateral incisor with an associated radicular lingual groove and severe periapical osseous destruction in a 30-year-old female patient. A combination of endodontic treatment, radiculoplasty to eliminate the radicular lingual groove, and periapical surgery to eliminate the periapical osseous defect was used. At two-year follow-up, the patient was comfortable and complete resolution of the periapical pathology was evident.     

Differential rates of enamel formation on human tooth surfaces deduced from the striae of retzius

Ten permanent maxillary central and mandibular lateral incisor teeth were sectioned in labio-lingual or mesio-distal planes, and the amount of enamel between two striae of Retzius was measured in the vicinity of the dentine-enamel junction. In the initial third of crown formation of central incisors, both the thickness of enamel and the amount of cervical extension of enamel were always greater on the labial than on the lingual surface; the same applied to the thickness of enamel, but not to the amount of cervical extension of enamel, in the lateral incisors. The thickness of enamel together with its cervical extension was greater on the mesial than on the distal surface in the lateral, but not the central, incisors. In the cervical third of the crown, there was a general tendency for the thickness of enamel and its cervical extension to be greater on the lingual and distal surfaces than on the opposite surfaces. For the maxillary central incisors, it was deduced that the labio-lingual reversion of the rate of development of enamel takes place at approximately the 60 per cent level of the crown formation.     

前突患者上切牙内收前的牙根吸收状况及因素分析

目的 调查前突患者上切牙内收前的牙根吸收状况,并且对该阶段牙根吸收的影响因素进行初步的探索.方法 选择上颌需要拔除双侧第一前磨牙且需要强支抗的前突患者50名,分别于正畸治疗前（T1）和上切牙内收前（T2）拍摄上颌切牙的平行投照根尖片和头颅侧位片,通过测量和评价,得到每颗切牙的牙根吸收量、治疗前牙根形态及上中切牙的角度位置及变化量,并记录其他诊断和治疗因素.对牙根吸收量作描述性统计,对各因素作多因素分析.结果 ①前突患者上切牙内收前,中切牙的牙根吸收平均为（0.73±0.53）mm,侧切牙为（0.84±0.70）mm.②有3％的中切牙和6％的侧切牙牙根吸收大于2mm.③多元线性回归表明T1期牙根形态异常、内收前疗程长、上中切牙根尖距唇侧骨皮质的距离减小量大、T1期U1/PP角小、上颌前部拥挤为中切牙牙根吸收的危险因素.T1期牙根形态异常、上颌前部拥挤、内收前疗程长、T1期牙齿长度长为侧切牙牙根吸收的危险因素.结论 前突患者上切牙内收前有一定量的牙根吸收,个别高危患者其牙根吸收状况较严重.我们的研究因素中存在此阶段与上切牙牙根吸收相关的因素,但这些因素对于牙根吸收的解释仅为30％左右.     

The prevalence, location and conformation of palato-radicular grooves in maxillary incisors

Palato-radicular grooves in maxillary lateral incisors have been implicated as an initiating factor in localized gingivitis and periodontitis. Focal loss of periodontal attachment associated with these grooves, some of which may extend to the apical third of the root, could result in a hopeless prognosis for tooth retention. There is disagreement as to the prevalence of this anomaly. As well, little is known about the shape, location and length of the defect. This study examined 3168 extracted maxillary lateral and central incisors. Of these teeth 4.6% had a palato-radicular groove. About half of the grooves terminated on the root and 58% of these extended more than 5 mm from the cementoenamel junction. A poorly described deformity, displacement of the cementoenamel junction, occurred in 38% of the grooves which crossed that structure. Although an extension of enamel in the groove has been suggested as a possible factor in the progression of localized periodontal disease, its presence was rarely observed.     

The morphological studies of root resorption of maxillary primary canines and their relation with the position of successive permanent teeth using Micro-CT

The purpose of this study is to clarify the root resorption of maxillary primary canines in relation to the development of successive permanent teeth. It was observed the maxilla of dry skulls of Indian children, using Micro-CT, and measured shortest distance between the root surface of maxillary primary canine and the bony crypt of maxillary canine. The bony crypt including successive canine was positioned almost directly above the root of primary canine and located superior to another bony crypts in the primary dentition stage. When the first molars reached the alveolar crest in addition to the primary dentition stage, the bony crypt of canine grew, showing the distal inclination of the superior margin and mesial inclination of the inferior margin. After the stage which is central incisors reached the alveolar crest, root resorption of primary canines was observed on the lingual side nearby the root apex and the bony crypt of canine was adjacent to the nasal cavity. It was quantitatively shown that the distance between the roots of primary maxillary canine and canine bony crypts reduced from central incisors reached the alveolar crest to lateral incisors reached that.     

Anatomical study of the root apex in the maxillary anterior teeth.

The purpose of this study was to investigate anatomically the apical portion of the root canal of human maxillary anterior teeth. Thirty maxillary central incisors, 30 maxillary lateral incisors, and 30 maxillary cuspids were used. These were teeth from patients ranging in age from 11 to 73 yr. The root apex and main apical foramen coincided in 16.7% of central incisors and cuspids and in 6.7% of the lateral incisors. The labiolingual diameter of the root canal at the apical constriction of the central incisors, lateral incisors, and cuspids averaged 0.425 mm, 0.369 mm, and 0.375 mm, respectively; and the respective vertical distances between apex and apical constriction were 0.863 mm, 0.825 mm, and 1.010 mm.     

Morphological studies on the roots of maxillary premolars in Japanese

Visual observations were made of 3,202 maxillary first premolars and 3,365 maxillary second premolars from subjects of known sex, age, and side attributes. The material belongs to the Okamoto Research Laboratory of Dentistry. Items observed for each donor included number of dental roots, shapes of root apexes, root grooves, root orientation and curvature, and conditions of the maxillary first and second premolars. Results 1) In 65.7% of all materials (55.4% in males and 76.1% in females), maxillary first premolars had primary single roots. Complete branched roots accounted for 25.5% of the male and 17.6% of the female materials. In both cases, there was significant distinction between the sexes. Triple root teeth were extremely rare in both male- and female-donor teeth, as were double rooted maxillary second premolars. 2) Protruding, circular, and flat root apex types occurred in both maxillary first and second premolars. Circular and flat types were common among males. Branched and double-root maxillary first and second premolars were of either the complete or the incomplete type, both of which were more common in males. 3) About half of the mesial surface grooves in single-root maxillary first premolars were deeper than distal surface grooves in the same teeth: In 1/4-branch double teeth, 28.8% of the mesial surface grooves were deeper than the distal-surface grooves. The corresponding percentage for 1/3-branch double teeth was 38.8%. In 7.6% of 1/4-branch and 17.4% of 1/3-branch double teeth, distal-surface grooves were deeper than mesial-surface grooves. In 36.4% of 1/4-branch double teeth and 28.9% of 1/3-branch double teeth, the lower portion of the root was web shaped. In maxillary first premolars, lingual roots of 1/3-branch double-root teeth were cylindrical, as were 28.9% of buccal roots. Root grooves occurred on the lingual sides of 61.7% of all specimens. For 1/2-branch double root teeth, 18.4% were cylindrical: and 62.7% had grooves on the lingual side. Results are essentially the same in both cases. 4) Straight dental roots occurred in 37.4% of maxillary first and 35.4% of maxillary second premolars. Roots inclined distally in 36.7% of maxillary first premolars and in 18.8% of maxillary second premolars. A variety of inclinations and curvatures was observed. Booth roots were straight in 47.5% of 2-branch maxillary first premolars, whereas 35.1% had 1 straight and 1 inclined root and 84.4% had 2 distally inclined roots.(ABSTRACT TRUNCATED AT 400 WORDS)     

Root canal therapy of an anomalous maxillary central incisor: a case report

Abstract A case of endodontic conservative treatment of a maxillary central incisor with an atypical crown and Type III dens invaginatus is presented. The greatest difficulty was to locate the root canals due to the atypical internal anatomy. There were not two clear canals, but the coronal pulp chamber showed two entrances to the root canal. The tooth presented a distal periodontal pocket and various lingual radicular grooves. The appearance of the crown was improved by alteration of its dimension using diamond rotary instruments and correction with photopolymerized resin.     

A micro-computed tomographic analysis of maxillary lateral incisors with radicular grooves

Introduction

The radicular groove is clinically significant due to its relevance to onset of inflammatory processes in the periodontal tissues. This study examined anatomic features of radicular grooves by using micro-computed tomography (micro-CT) scans.

Methods

Eleven extracted permanent maxillary lateral incisors with radicular grooves were collected from a native Chinese population and were scanned by micro-CT scans. The specimens were reconstructed three-dimensionally by software Mimics 10.01 (Materialise, Leuven, Belgium). The grooves were classified into three types on the basis of severity.

Results

Three specimens presented type I grooves (apically not beyond the coronal third of the root); five specimens showed a type II groove (beyond coronal third, corresponding to a normal or simple root canal), and three showed a type III groove (beyond the coronal third, corresponding to a complex root canal system). The developing groove could be located at the mesial (three teeth), distal (six teeth) and medial (one tooth) aspect of the root. In one specimen double grooves were found (a mesial and a distal). All specimens with type I grooves had normal root canal configuration. A cross-sectional teardrop-like canal was seen in a specimen with a type II groove. The C-shaped canal, invagination canal, and additional root with secondary canal were observed in specimens with type III grooves.

Conclusions

Understanding the anatomic features of the radicular groove is essential for successful dental treatment.     

Talon's cusp: report of four unusual cases

Talon cusp is a developmental dental anomaly thought to arise as a result of evagination on the surface of a tooth crown before calcification has occurred. The etiology remains unknown. The incidence is 0.04-10%. Any tooth may have a talon cusp but most of the cases involve maxillary lateral incisors, with some instances of bilateral involvement. The anomaly has been reported to be rare in the mandible. This article reports four cases of talon cusp. The first and the second cases describe bilateral involvement of talon cusp on palatal surfaces of maxillary primary centrals; in the third case talon tubercle occurs on palatal surfaces of both maxillary permanent lateral incisors and the maxillary left central incisor and in the last case a talon cusp in the lingual surface of mandibular permanent lateral incisor.     

A survey of approximal root concavities in an ethnic Chinese population

Eight hundred and forty teeth were surveyed, 60 approximal surfaces for each tooth type being studied. Approximal root concavities were completely absent in maxillary central incisors, in contrast with mandibular central incisors of which 73% had concavities on mesial surfaces and 93% on distal surfaces. Similarly, a markedly higher prevalence was found for mandibular lateral incisors and canines. However, mandibular first and second molars had fewer approximal concavities than their maxillary counterparts. In maxillary teeth, concavities were more frequent on distal surfaces, while for mandibular teeth no definite pattern was seen. In both maxillary and mandibular teeth, approximal concavities often started in enamel, extending down to the root surface. There were differences in the approximal root topography of Chinese teeth in comparison with other populations.     

The radicular palatal groove – a therapeutic modality

Abstract A radicular palatal groove may be present in about 8.5% of the population, mainly in maxillary lateral incisors. Often this condition predisposes periodontal defects and severe bone destruction, which have been considered untreatable, and extraction has been recommended as a solution. In this report a case is presented of a radicular palatal groove in a maxillary lateral incisor that caused an advanced periodontal defect and pulp necrosis. Like other such cases, this case presented first as an endodontic problem, and was diagnosed by the endodontist. Periodontal surgery failed to resolve the lesion. Filling of the groove by means of amalgam resulted in disappearance of symptoms and closure of the pocket, accompanied by restoration of the lamina dura. The suggested technique was advantageous over previously published treatment modalities, as it effectively eliminated the groove as a pathway of contamination, without loss of tooth substance and without exposure of cut dentin. It is also suitable for treating deep grooves communicating with the root canal.     

Normal torque of the buccal surface of mandibular teeth and its relationship with bracket positioning: a study in normal occlusion

This study evaluated the degree of buccolingual inclination of mandibular tooth crowns relative to torque. For such purpose, mandibular and maxillary stone casts from 31 Caucasian Brazilian adults with normal occlusion, pleasant facial aspect and no history of previous orthodontic treatment were examined. A custom device was developed for measuring the degree of inclination (torque) of bracket slots of orthodontic appliances relative to the occlusion plane, at three bonding height: standard (center of clinical crown), occlusal (0.5 mm occlusally from standard) and cervical (0.5 mm cervically from standard). Except for the mandibular incisors, which presented a small difference in torque from one another (lingual root torque for central incisors and buccal root torque for lateral incisors), the remaining average values are close to those found in the literature. Due to the convexity of the buccal surface, the 1-mm vertical shift of the brackets from occlusal to cervical affected the values corresponding to the normal torque, in approximately 2 degrees in central and lateral incisors, 3 degrees in canines and 8 degrees in premolars and molars.