Influence of bone anatomical morphology of mandibular molars on dental implant based on CBCT

Background To apply CBCT to investigate the anatomical relationship between the mandibular molar and alveolar bone, aimed to provide clinical guidelines for the design of implant restoration. Methods 201 CBCT data were reevaluated to measure height of the alveolar process (EF), width of the alveolar process (GH), width of the basal bone (IJ), the angle between the long axis of the first molar and the alveolar bone (∠a) and the angle between the long axis of the alveolar bone and basal bone (∠b). The angle and width were measured to determine the implant-prosthodontic classification of the morphology in the left lower first molar (36) and right lower first molar (46). All measurements were performed on the improved cross-sectional images. Results EF, GH and IJ were measured as (10.83 ± 1.31) mm, (13.93 ± 2.00) mm and (12.68 ± 1.96) mm for 36, respectively; and (10.87 ± 1.24) mm, (13.86 ± 1.93) mm and (12.60 ± 1.90) mm for 46, respectively. No statistical significance was observed in EF, GH, IJ, ∠a and ∠b between 36 and 46 (all P > 0.05). The morphology was divided into three categories including the straight (68.7–69.2%), oblique (19.9–20.4%) and concave types (11%). Each type was consisted of two subcategories. Conclusions The proposed classification could provide evidence for appropriate selection and direction design of the mandibular molar implant in clinical. The concave type was the most difficult to implant with the highest risk of lingual perforation. The implant length, width, direction required more attention.

Treatment Modalities of Recurrent Oral Mucosal Melanoma In Situ

Oral mucosal melanoma (OMM) represents an extremely rare entity that is associated with a poor prognosis due to late diagnosis and early metastasis. Here, extensive surgical therapy is the therapy of choice. In contrary, for OMM in situ, the respective therapeutical recommendations are lacking. In this case report, treatment modalities of an OMM in situ of the palate, including the maxillary alveolar process, are reported. The tumor relapsed twice despite adequate surgical therapy and reconstruction. Therefore, irradiation was performed as an adjuvant therapy. At a follow-up of two years, the patient was free from recurrences.

IMBALANCE OF ANTIOXIDANT-PROOXIDANT SYSTEM IN RAT'S JAW BONE TISSUE UNDER LONG-TERM INTRODUCTION OF ETHANOL

Introduction. Nowadays, it is unclear what the trigger for bone resorption under the influence of chronic alcohol consumption is. As the reactions of conversion of ethanol into acetic acid are accompanied by an increase in the production of reactive oxygen species, it can be assumed that the formation of oxidative stress with prolonged alcohol consumption occurs in bone tissue as well. Aim. Research of the effect of chronic administration of ethanol to females and males laboratory rats on indices of resorption, osteogenesis, the condition of the antioxidant-prooxidant system in bone tissue. Materials and Methods. 2-month old animals received from 5 % to 15 % of ethanol in their drinking water with gradual increase of the concentration. The lower jaws were segregated, and the degree of atrophy of the alveolar process was calculated. The activity of elastase, acidic (AcF) and alkaline phosphatase (AlF), superoxide dismutase (SOD), catalase, glutathione reductase and malonic dialdehyde (MDA) content were determined in the bone tissue homogenates. Results. Chronic alcohol consumption contributed to an increase in alveolar bone atrophy, increased activity of biochemical markers of bone resorption (elastase by 32.2 %, AcF – by 33.6 %), decreased osteogenesis (AlF activity by 32.4 %). Alcohol intoxication led to oxidative imbalance of bone tissue: a decrease in SOD activity by an average of 16.9 %, glutathione reductase activity by 36.2 %, increase in catalase activity by 35.9 % and an increase in MDA levels by 51.8 %. Conclusion. Chronic alcohol consumption stimulates atrophy of the alveolar process of the rat jaw, induces oxidative imbalance in bone tissue, which can be a trigger pathogenetic factor in further development of resorption pro-inflammatory processes in bone tissue and inhibition of bone formation.

CLINICAL PECULIARITIES OF WOUND HEALING IN THE POSTOPERATIVE PERIOD OF SURGICAL TREATMENT OF ALVEOLAR PROCESS ATROPHY OF THE UPPER JAW AND PART OF THE LOWER JAW IN POSTMENOPAUSAL WOMEN

Introduction. Atrophy of the alveolar process of the upper jaw and part of the lower jaw is often observed after the tooth extraction. It is known that the atrophy of bone tissue is most likely observed in the first 12 months after the tooth extraction. According to the Koln classification, atrophy of the bone tissue of the jaws can be vertical, horizontal and combined. The aim of surgical treatment of jaw bone tissue atrophy is to increase the size in the area of alveolar process of the upper jaw and part of the lower jaw to further restoration of masticatory function, in particular with the use of dental implants. The aim of the study: to study the dynamics of wound healing in postmenopausal women with osteopenia after surgical treatment of jaw bone tissue atrophy using osteoplastic material and ossein-hydroxyapatite compound. Materials and methods of the study. There were observed 63 postmenopausal women with osteopenia, aged from 50 to 59 years, with atrophy of the maxillary and mandibular alveolar process, who were performed surgical treatment. During surgery, patients were divided into 3 groups: Group I – 23 patients with atrophy of the alveolar process of the upper jaw and part of the lower jaw with osteopenia, with the reduced bone tissue density, who were treated surgically for bone tissue atrophy using the method worked out by us. Group II – 23 patients with atrophy of the alveolar process of the upper jaw and part of the lower jaw with osteopenia, with the reduced bone density who were performed surgical treatment of atrophy of the jaw bone tissue using osteoplastic material of animal origin. Group III – 23 patients with atrophy of the alveolar process of the upper jaw and part of the lower jaw with the indices of bone tissue density within normal limits, who were performed surgical treatment of atrophy of the jaw bone tissue using osteoplastic material of animal origin. The results of the study. A total of 69 edentulous areas on the upper and lower jaws were examined after surgery for the treatment of jaw bone tissue atrophy. Examination of the postoperative wound was performed during the 3rd, 9th, and 14th day in the absence of complaints from patients during this period, as well as in the presence of signs of complications. Discussion of the results. According to the offered by us method of decortication of the bone tissue of the jaws, which was used to treat patients of group I, the blood supply to the postoperative area and infiltration of bone material with blood due to provoked by decortication of bone tissue bleeding, are improved. Impregnation of bone material with blood promotes angiogenesis in the postoperative area, increasing cellular activity during wound healing. It is known that due to the absence of sufficient blood supply, tissue necrosis occurs [8,9]. In patients of groups II and III the complete healing of the postoperative wound with primary tension took longer than in patients of group I. Also, in 3 patients of group II and in 1 patient of group III the wound dehiscence in the postoperative area was observed. Conclusions. As a result of the performed observations of wound healing after surgical treatment of jaw bone tissue atrophy in patients of groups I, II and III, the least complications were observed in patients of group I in the early postoperative period.

Basal Implant: A Remedy to Restore Resorbed Alveolar Ridges

The conventional crestal implants are used only when there is adequate jawbone height and width. Results of conventional implants are good in patients with healthy bone at the time of treatment, but prognosis gets deteriorated when surgical augmentation of bone is included with implant placement. These augmentation procedures have surgical risks and are costlier to the patients. Patients with atrophied jawbones are given no treatment, until crestal implants are seen as the last option. In this article, the indications for basal implants and functional differences between basal implants and crestal implants have been discussed.Patients with extreme jawbone atrophy do not benefit from crestal implants. The basal bone is the (cortical) osseous tissue of the mandible and maxilla, and lies below the alveolar process, which has a relatively strong and no resorbing framework.Basal osseointegrated and basal cortical screw (BCS) are two types of implants designed to take anchorage from the cortical bone of the jaw. BCS implants have long shafts and can be placed immediately in the socket after extraction and provided with immediate loading within 72 hours of implant placement. Basal implants are also called bicortical or cortical implants as they utilize the cortical portion of the jawbones for anchorage and implant stability. The basal bone has better quality and quantity of cortical bone for retention of these unique and highly advanced implants. The other names for these implants are lateral implants or disk implants.