Mandibular First Molar Region Research Articles

BUCCAL BIFURCATION CYST: A REPORT OF 2 CASES

Buccal bifurcation cyst (BBC) is an uncommon inflammatory odontogenic cyst, often affecting the buccal region of the permanent mandibular first molars in pediatric patients. Diagnosis is primarily based on strict correlation of the clinical, imaginologic, and microscopic findings. Case 1: A 13-year-old male patient was referred after presenting with a nodular swelling with several months of evolution. Imaginologic analysis showed a well-delimited vestibular cortical bone expansion at the level of tooth #47. Case 2: An 11-year-old male patient was referred after presenting with a swelling with 6 months of evolution at the level of tooth #36. Computed tomography showed a vestibular expansive, hypodense lesion, with cortical bone preservation. In both cases, excisional biopsy with tooth preservation was performed. In the follow-up, healthy periodontium of the involved teeth was observed. In both cases, after clinicopathologic correlation, a BBC diagnosis was made. BBC should be considered in the differential diagnosis of expansive cystic or benign lesions affecting permanent mandibular molars. Buccal bifurcation cyst (BBC) is an uncommon inflammatory odontogenic cyst, often affecting the buccal region of the permanent mandibular first molars in pediatric patients. Diagnosis is primarily based on strict correlation of the clinical, imaginologic, and microscopic findings. Case 1: A 13-year-old male patient was referred after presenting with a nodular swelling with several months of evolution. Imaginologic analysis showed a well-delimited vestibular cortical bone expansion at the level of tooth #47. Case 2: An 11-year-old male patient was referred after presenting with a swelling with 6 months of evolution at the level of tooth #36. Computed tomography showed a vestibular expansive, hypodense lesion, with cortical bone preservation. In both cases, excisional biopsy with tooth preservation was performed. In the follow-up, healthy periodontium of the involved teeth was observed. In both cases, after clinicopathologic correlation, a BBC diagnosis was made. BBC should be considered in the differential diagnosis of expansive cystic or benign lesions affecting permanent mandibular molars.

Evaluation of trabecular bone changes in patients with periodontitis using fractal analysis: A periapical radiography study.

The present study was aimed to evaluate the trabecular bone changes between healthy individuals and periodontitis patients with fractal dimension analysis on digital periapical radiographs. Data from 35 healthy and 35 individuals with periodontitis were confirmed from the database of our faculty and included in the study. Two regions of interest (ROI) were selected belonging to mesial and distal region of mandibular first molar on periapical radiographs. The mean fractal dimension (FD) values of two regions were calculated with using box-counting method. Student t test was used for the comparison of the FDs. The mean FD of individuals with periodontitis was 0.97, whereas it was 1.04 for the healthy group. The mean FD values were significantly higher in the healthy group (P<0.05). In the periodontitis group, as the FD of mesial interdental bone increased, the FD of distal interdental bone increased significantly (P<0.05). Because of FD numerically showing changes in bone trabeculation, changes in the alveolar bone can be detected quantitatively.

Buccal bifurcation cyst as an incidental finding in cone beam computed tomography scans

ABSTRACT Buccal bifurcation cyst is an unusual inflammatory odontogenic cyst of unknown etiology which occurs at the buccal region of the permanent mandibular first molars in children and adolescents aged 6-15 years old. The aim of this manuscript is to present two clinical cases of buccal bifurcation cyst incidentally detected in adolescents referred for tomographic exams (CBCT) as part of the treatment planning for the management of impacted mandibular molars. The first case is very interesting due to the proximity of the lesion to the inferior alveolar canal. In the second case the inferior alveolar canal was not in close proximity to the lesion, but in contact with the mesiobuccal root of the second molar. The diagnosis of Buccal bifurcation cyst is of utmost importance in order to avoid complications during surgical procedures. In addition, the present case reports have highlighted the importance for dental practitioners to be aware of the possibility of a buccal bifurcation cyst being present as an incidental finding in CBCT images, especially in young patients.

A study to assess the bone formed around immediate postextraction implants grafted with Concentrated Growth Factor in the mandibular posterior region

Aim Extraction of the teeth and a healing period of 4-6 months followed by implant placement is a common procedure for the treatment of teeth with bad prognosis. This study was done to assess radiographically the quantity and quality of bone formed in the region of mandibular first molar after extraction of the tooth and immediate implant placement with Concentrated Growth Factor (CGF) grafting. Materials and methods A total of 10 subjects were selected for this prospective study. Extraction of mandibular first molars was carried out and implants were immediately placed with CGF grafting. A Cone Beam Computed Tomography (CBCT) was taken immediately after implant placement and after six months of undisturbed healing, radiographic evaluation was carried out using CBCT to assess the quantity and quality of new bone formed around implants. The collected data were statistically analyzed. Results CBCT results showed a mean bone gain of 2.3 mm in buccal, 1.52 mm in lingual, 2.97 mm in mesial and 4.26 mm in distal aspect respectively. No statistically significant change was noticed in bone density comparing the first two and last two threads of implants inserted with concomitant placement of CGF into the extraction socket. Conclusion This study indicates the possibility to perform immediate implant placement in fresh extraction sockets with the use of CGF as an alternative to conventional grafting. Further research needs to be carried out on the subject to validate the results obtained in this study.

Downregulation of Proteinase-Activated Receptor-2, Interleukin-17, and Other Proinflammatory Genes by Subantimicrobial Doxycycline Dose in a Rat Periodontitis Model.

Subantimicrobial dose doxycycline (SDD) has been used as an adjunct in periodontal treatment because of its matrix metalloproteinase inhibition properties. Although the benefits of SDD therapy, such as improvement in the parameters of periodontal probing depth and clinical attachment level, have been proven in multiple clinical studies, the comprehension of other biologic mechanisms of action on periodontitis remains poorly investigated. Therefore, this animal-model study evaluated the effects of SDD monotherapy on the expressions of the following key proinflammatory genes: proteinase-activated receptor-2 (PAR2), tumor necrosis factor (TNF)-α, interleukin (IL)-17, and IL-1β. Male Wistar rats were assigned randomly to the following: 1) control group: no ligature-induced periodontitis and no treatment; 2) ligature group: ligature-induced periodontitis and placebo treatment; and 3) ligature + doxycycline group: ligature-induced periodontitis and SDD treatment. After the experimental time, animals were sacrificed, and reverse transcription-polymerase chain reaction was performed to analyze the mRNA expression of IL-1β, IL-17, TNF-α, and PAR2 in gingival tissue samples. Histologic analyses were performed on the furcation region and mesial gingiva of mandibular first molars to measure periodontal bone loss and collagen content. SDD administration significantly downregulated PAR2, IL-17, TNF-α, and IL-1β mRNA expressions (P <0.05). In addition, SDD treatment was accompanied by lower rates of alveolar bone loss (P <0.05) and maintenance of the amount of gingival collagen fibers. These findings reveal new perspectives regarding SDD efficacy because it can be partially related to proinflammatory gene expression modulation, even considering PAR2 and IL-17, which has not been investigated thus far.

A bar and ball attachment prosthesis over osseointegrated implants post mandibular resection

Rehabilitation of mandibular resection poses functional, esthetic, and psychological challenges. The deviation and rotation of the mandible toward the resected side leaves the patient with almost no option of chewing. This is aggravated if the patient is edentulous. The case report discussed in this article was an edentulous patient taken up with the primary goal to limit deviation toward resected side and provide a stable and retentive prosthesis to the patient. Two implants were placed anteriorly, splinted with bar and clip supported superstructure. The splinted implants with bar and clip superstructure provided the mandibular prosthesis with retention and some support. A posterior implant was also placed in the region of mandibular first molar on the left side for added support. This provided with a tripod configuration and limited the prosthetic movement of the mandibular prosthesis. This case report highlights an alternate way toward the rehabilitation of edentulous mandible post mandibular resection when surgical reconstruction may not be feasible.

Fluoxetine Inhibits Inflammatory Response and Bone Loss in a Rat Model of Ligature‐Induced Periodontitis

Fluoxetine, a selective serotonin reuptake inhibitor, has been found recently to possess anti-inflammatory properties. The present study investigates the effects of fluoxetine on inflammatory tissue destruction in a rat model of ligature-induced periodontal disease. Thirty male Wistar rats were randomly assigned into three groups (n = 10 animals per group): 1) control rats (without ligature); 2) rats with ligature + placebo (saline; oral gavage); and 3) rats with ligature + fluoxetine (20 mg/kg/day in saline; oral gavage). Histologic analyses were performed on the furcation region and mesial aspect of mandibular first molars of rats sacrificed at 15 days after ligature-induced periodontal disease. Reverse transcription-polymerase chain reaction and zymography were performed to analyze the mRNA expression of interleukin (IL)-1β, cyclooxygenase (COX)-2, matrix metalloproteinase (MMP)-9 and inducible nitric oxide synthase and the MMP-9 activity, respectively, in gingival tissues samples. Compared to the ligature + placebo group, alveolar bone loss was reduced in the fluoxetine group (P <0.05), and the amount of collagen fibers in the gingival tissue was maintained. Moreover, in gingival tissue sampled 3 days after ligature attachment, fluoxetine administration reduced IL-1β and COX-2 mRNA expression. Fluoxetine downregulated MMP-9 activity, without affecting MMP-9 mRNA expression induced by ligature, compared to the ligature + placebo group (P <0.05). These data suggest that fluoxetine suppressed proinflammatory responses, as well as proteolytic enzyme activity, induced by ligature. In the present study, fluoxetine suppresses the inflammatory response and protects against periodontal bone resorption and destruction of collagen fibers, suggesting that fluoxetine can constitute a promising therapeutic approach for periodontal diseases.

Odontoblast-targeted Bcl-2 overexpression promotes dentine damage repair

ObjectiveBcl-2 is widely expressed in a developing tooth organ and regulates tooth morphogenesis. However, whether Bcl-2 is related to tooth damage repair is unknown yet. Using an odontoblast-targeted Bcl-2 overexpression transgenic mouse (Col2.3Bcl-2) and artificial cavity preparation as a model system, the relationship between Bcl-2 and reparative dentinogenesis is investigated in this study. MethodsThe odontoblastic-like cell cultures derived from mouse molar pulps were established. The expression of transgenic human Bcl-2 (hBcl-2) and endogenous mouse Bcl-2 (mBcl-2) and mouse Bax (mBax, a Bcl-2 antagonist) was detected in vivo and in vitro by Western blot and immunocytochemistry, respectively. Basal level and artificial cavity-induced odontoblast apoptosis was detected by the Deoxynucleotidyl Transferase (TdT) dUTP Nick End labelling (TUNEL) technique. Reparative dentine formation induced by artificial cavity drilled to a half dentine thickness on mesial cervical region of mandibular first molars 2, 4, and 6 weeks post-op was evaluated histologically and via micro-CT. ResultsThe transgenic hBcl-2 was stably expressed in odontoblasts of the transgenic animals without interference with the expression of mBcl-2 and mBax. Basal level as well as artificial cavity- induced odontoblast apoptosis was prevented by the transgene. Compared to the wild type, the transgenic animals produced reparative dentine with significantly higher mineral density 6 weeks after the operation. ConclusionsBcl-2 overexpression prevents odontoblast apoptosis and promotes dentine damage repair, indicating that genetic manipulation of Bcl-2 may be a novel strategy to maintain the vitality and function of dentine-pulp complex under detrimental mechanical stimuli.

Poster 027: A Case of Deep Neck Abscess by Which Ring Enhancement of the External Jugular Vein Became an Indicator of the Diagnosis

It is well known that contrast-enhanced CT is useful for diagnosis of deep neck abscess. The characteristic findings are: (1) single cystic or multiloculated low-density findings; (2) contrast enhancement of the abscess wall; (3) edema surrounding the abscess; (4) anatomical boundaries that fit the fascial spaces; and (5) air and/or fluid at the center of the abscess. However, little is known about the nature of the inflammatory reaction. Herein, we report an abnormal case of deep neck abscess developing from odontogenic infection. In this case, rapid spread of the inflammation was demonstrated and there was a lack of characteristic CT findings to suggest the formation of abscess. The patient was a 46-year-old woman with swelling in the right parotid region complicated by right inferior alveolar neuroparalysis. The patient’s medical history included diabetes (HbA1C 12%). Although the patient reported oppressive pain in the right parotid region at the first medical examination, the range of swelling was ambiguous because the neck was thick and short. It was only the intraoral view that showed slight redness in the right mandibular first-molar region. The right parotid gland showed diffuse swelling on contrast-enhanced CT, but there were no signs of a clear abscess. However, there was ring enhancement of the right external jugular vein extending for about 11cm from the inferior pole of the parotid gland, and circumferential edema was also noted. The WBC was 15100/ul and CRP was 25 mg/dl. She was given a diagnosis of right mandibular osteomyelitis and cervical cellulites caused by an odontogenic infection of the right mandibular first-molar. Although antimicrobial therapy and blood sugar management were started under hospitalization, there was no reduction of inflammation. Based on the range of ring enhancement of the right external jugular vein, the region was incised and pus was drained from the superficial layer of the cervical fascia. This experience suggests that ring enhancement of the vein was an indicator of abscess on contrast-enhanced CT.

ケルビズムの１例

Cherubism is an uncommon disease in Japan that was first described by Jones as a familialmultilocular cystic disease of the jaws. The disease is classified as a non-neoplastic bone lesion in the World Health Organization histological typing of odontogenic tumors, but diagnostic criteria have notbeen established.We report a non-familial case of cherubism in a 10-year-old boy. The patient clinically showed fullness of the cheeks, slightly upturned eyes, and multiple swellings of the submandibular and cervical lymphnodes. Intraorally, there was bilateral bone expansion from the mandibular first molar region to the ascendingramus. The right first molar was dislocated laterally and the left first molar was unerupted.Radiographically, multilocular radiolucent lesions were found bilaterally from the mandibular firstmolar region to the coronoid process. In addition, there were unilocular radiolucent lesions from the maxillary molar region to the tuberosity on both sides. Biopsy specimens obtained from the mandibular lesionswere diagnosed as giant cell granuloma. The patient is being examined periodically with no treatment. The lesions have shown no evidence of growth for 16 months.

Endotoxin and Gram-negative bacteria in the rat periapical lesions

The purpose of this study was to measure the amount of endotoxin as well as to identify Gram-negative bacteria in experimental periapical lesions in rats. Molar pulps were exposed and infected and the amount of endotoxin in the periapical tissue of the right mandibular first molar was measured by Endospecy, while the colony number of Gram-negative bacteria was determined in the same region of the left mandibular first molar. In the control animals, the amount of endotoxin in the periapical tissues did not change at all during the experimental period, and no Gram-negative bacteria were isolated. In the experimental animals, the amount of endotoxin in the periapical tissues increased gradually from 1 to 70 days, and its level was significantly greater than that of control animals after 7 days. Gram-negative bacteria were isolated from the periapical tissues and their number gradually increased from 1 to 14 days (26 to 82%), but decreased at 21 days. It was approximately 60% from 28 to 70 days. The results of this study showed that the amount of endotoxin in the periapical tissues gradually increased with increasing time and that Gram-negative bacteria were isolated from the same region but did not increase in number concurrently with the increase in the amount of endotoxin.

Emergency Endodontic Therapy: Report of Case

In emergency situations relief of a patient’s discomfort, caused by a diseased pulp, may be obtained with use of a deep pulpotomy procedure. A 23-year-old woman was seen late at night because of pain in the region of the right mandibular first molar. A diagnosis of irreversible pulpitis was made. After anesthesia had been obtained, the roof of the pulpal chamber was removed completely. The chamber was debrided and the canals were instrumented to a depth of 16 mm. A medicated pellet was placed in the chamber and the access opening was closed with a temporary cement restoration. The patient was instructed to see her dentist for complete endodontic therapy. In emergency situations relief of a patient’s discomfort, caused by a diseased pulp, may be obtained with use of a deep pulpotomy procedure. A 23-year-old woman was seen late at night because of pain in the region of the right mandibular first molar. A diagnosis of irreversible pulpitis was made. After anesthesia had been obtained, the roof of the pulpal chamber was removed completely. The chamber was debrided and the canals were instrumented to a depth of 16 mm. A medicated pellet was placed in the chamber and the access opening was closed with a temporary cement restoration. The patient was instructed to see her dentist for complete endodontic therapy.