• Imaging Science in Dentistry
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• v.53 no.3
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• pp.199-207
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• 2023

Purpose: The objective of this study was to evaluate the accuracy and effectiveness of an artificial intelligence (AI) program in identifying dental conditions using panoramic radiographs(PRs), as well as to assess the appropriateness of its treatment recommendations. Materials and Methods: PRs from 100 patients(representing 4497 teeth) with known clinical examination findings were randomly selected from a university database. Three dentomaxillofacial radiologists and the Diagnocat AI software evaluated these PRs. The evaluations were focused on various dental conditions and treatments, including canal filling, caries, cast post and core, dental calculus, fillings, furcation lesions, implants, lack of interproximal tooth contact, open margins, overhangs, periapical lesions, periodontal bone loss, short fillings, voids in root fillings, overfillings, pontics, root fragments, impacted teeth, artificial crowns, missing teeth, and healthy teeth. Results: The AI demonstrated almost perfect agreement (exceeding 0.81) in most of the assessments when compared to the ground truth. The sensitivity was very high (above 0.8) for the evaluation of healthy teeth, artificial crowns, dental calculus, missing teeth, fillings, lack of interproximal contact, periodontal bone loss, and implants. However, the sensitivity was low for the assessment of caries, periapical lesions, pontic voids in the root canal, and overhangs. Conclusion: Despite the limitations of this study, the synthesized data suggest that AI-based decision support systems can serve as a valuable tool in detecting dental conditions, when used with PR for clinical dental applications.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.305-324
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• 2000

This study compared the short-term(4 months) clinical results of regenerative therapy with bioabsorbable membranes($BioMesh^{(R)}$) and bone allograft for the treatment of periodontal(intrabony and furcation) defects in smokers and nonsmokers.(16 smokers) 32 subjects with 92 defects participated in the study(46 in smokers and 46 in non-smokers). This study also evaluated a bioresorbable barrier with and without decalcified freeze-dried bone allograft(DFDBA). The 92 periodontal defects were randomly treated with either the resorbable barrier alone or resorbable barrier in combination with DFDBA following thorough defect debridement and root preparation with tetracycline. Each patient received both types of treatment modalities. Clinical examinations(probing depth, gingival recession, clinical attachment level, plaque index and gingival index) were carried out immediately before and 4 months after surgery. Significant(p<0.001) gains in mean attachment level were observed for both smokers(2.93mm) and non-smokers(3.30mm) but there were not significant difference between two groups. Similarly, significant reductions in mean probing depthshowed for smokers(4.52mm) and non-smokers(4.26mm). However, when comparing gingival recession, smokers were found to exhibit significantly poorer treatment results(1.59mm vs 0.96mm, p<0.05). Using the split-mouth-design, no statistically significant difference between the two modalities could be detected with regard to pocket depth reduction, gingival recession, or attachment gain. These results illustrate that the attachment gain is better in the non-smoker and the best in the non-smoker with the combination therapy of resorbable barrier and DFDBA than with resorbable barrier alone but smoking had no significant effect on clinical treatment outcome, even though smokers show more significant gingival recession. In addition, both treatments, either resorbable barrier plus DFDBA or resorbable barrier alone, promoted significant resolution of periodontal defects but the addition of DFDBA with a bioabsorbable membrane appears to add no extra benefit to the only membrane treatment.

• Journal of Dental Rehabilitation and Applied Science
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• v.39 no.1
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• pp.1-8
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• 2023

Purpose: The purpose of this study is to analyze the prognostic factors related to tooth loss after 5 years of periodontal surgery in periodontal disease patients. Materials and Methods: From January to December 2017, 22 patients and 124 teeth who underwent periodontal treatment through periodontal surgery were targeted. At the time of treatment, the measured values were evaluated after recording the maximum probing depth, average periodontal probing depth, number of root, furcation involvement, pulp vitality, and prosthesis state on the day of periodontal surgery. Based on the initial records at the time of visit, patient-related factors were gender, age, smoking, tooth loss due to periodontal disease at the time of first visit, diabetes, and maintenance period. The influence of each factor on tooth loss was evaluated. Results: As a result of examining the influence of tooth-related factors on tooth loss, the maximum probing depth depth (P: 0.000), bone loss (P: 0.021) was found to have a significant effect on tooth loss. Conclusion: As a result of examining the influence of patient-related factors on tooth loss, any variables had no significant effect. Bone loss, maximum probing depth acted as statistically significant prognostic factors for tooth loss in patients who underwent periodontal surgery.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.739-750
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• 1997

Treatment of root perforation elicits special considerations due to its blood-contaminated circumstances. It is known that conventional dental restorative materials are all leaking. Calcium sulfate is the material which react with water to become chemically set. This study, therefore, was performed to develop a new compound containing calcium sulfate and to evaluate its physical and biological characteristics. Three materials were used, IRM, calcium sulfate, calcium sulfate-hydroxyapatite compound. The composition of the calcium sulfate-hydroxyapatite compound was basically 50 % of calcium sulfate and 50 % of hydroxyapatite mixed with guajacol. The materials were mixed in conventional way and underwent four physical test procedures, setting time, solubility test, compressive strength, and marginal leakage test. All materials were evaluated under the scanning electron microscope to examine the marginal sealing ability. Animal experiment was also performed to test the materials' tissue response. Twenty-four dog's premolars were tested with either furcation perforations or apical retro-fillings. From the results, we found that calcium sulfate possess the good marginal sealing ability. However, calcium sulfate creates many voids which is caused by crystal thrusting action when it reacts with water. It seemed that the voids caused disintegration of the material which eventually lead to tissue reaction. By compounding calcium sulfate and hydroxyapatite, we were able to obtain the better physical properties but it showed larger marginal gap between the material and the root surface. Within the six weeks observation period, both IRM and calcium sulfate-hydroxyapatite compound showed good tissue responses in animal experiment. It is concluded that calcium sulfate would be the material of choice in root perforation repair, but the physical property needs to be further improved.

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.61-68
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• 2002

The objective of this study was to determine the incidence and distribution of root fusion as well as its sexlinkage in maxillary and mandibular molars. One hundred fifty patients who had eight maxillary and mandibular molars (third molars excluded) were consecutively selected for the study subjects. The subjects provided a total of 1200 molars, i.e., 600 maxillary and 600 mandibular molars. A decision about root fusion was made on the radiographic examination. If a molar had one root and/or roots fused at any part in the root surface, it was considered as having root fusion. The results showed that : (1) 14.1 % of the maxillary molars and 5.8 % of the mandibular molars had a fused root, (2) the prevalence of root fusion in the male was 33 % and 56.4 % in the female, (3) 60 % in the male and 48.8 % in the female had bilaterally paired root fusion, (4) the root fusion was most frequently observed in the maxillary second molar position, but none in the mandibular first position in this study. Within limitations of this study, it can be concluded that, in management of molars with a furcation problem, treatment options such as hemisection and root amputation should be chosen after careful evaluation of root fusion. Further studies are needed to investigate a possible relationship between root fusion and periodontal disease progression.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.4
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• pp.308-316
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• 2006

Objectives Despite considerable advances in technique, experience and skill, the precise place of surgery in the treatment of facial nerve injury remains uncertain. We designed a facial nerve crush injury model in rats and evaluated the recovery of crushed nerve which is the most common injury type of facial nerve using adenovirus vector mediated in vivo gene transfer of Brain derived neurotrophic factor(BDNF). Materials and methods In 48 Sprague Dawley rats, we made a facial nerve crush injury model to main trunk before the furcation, and injected a $10^{11}$pfu adenoviral BDNF in experimental group(BDNF adenoviral injection group; ad-BDNF) and $3{\mu}l$ saline in control group(Saline injection group; saline). After a period of regeneration from 10 to 40 days, nerve regeneration was evaluated with functioinal test (vibrissae and ocular movement), electrophysiologic study(threshold, peak voltage, conduction velocity) and histomorphometric study of axon density. Results Vibrissae and ocular movement, threshold and conduction velocity improved as time elapse in both group, however axon density was increased significantly only in experimental group. Functional test in 10 days and 20 days showed no difference between experimental group and control group. Vibrissae movement, threshold, conduction velocity and axon density in 30 days revealed that the regeneration in quality of experimental group was significantly superior to that of control group. Conclusion In general, there is tendency for nerve regeneration in experimental group (BDNF-adenovirus injection group) during 40 days, functional recovery was detected successfully after facial nerve crush in 30 days postoperatively.

• Journal of Periodontal and Implant Science
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• v.50 no.1
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• pp.38-47
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• 2020

Purpose: The aim of this study was to investigate the available alveolar bone height between the maxillary molars and the sinus floor according to their anatomical relationship using cone-beam computed tomographic (CBCT) images. Methods: A total of 752 maxillary first (M1) and second molars (M2) on CBCT scans of 188 patients were selected. First, each maxillary molar was categorized as type 1, 2, 3, or 4 according to the relationship of the molar root with the maxillary sinus floor. The frequency distribution of each type was analyzed. Second, the shortest vertical distance (VD) of each molar was measured from the furcation midpoints of the roots to the lowest point of the sinus floor by 2 observers. Intraclass correlation coefficients and the t-test were calculated for the VD measurements. Results: For M1, type 3 was the most frequent, followed by type 2. For M2, type 3 was the most common, followed by type 1. The VD measurements of type 1 were 9.51±3.68 mm and 8.07±2.73 mm for M1 and M2, and those of type 3 were 3.70±1.52 mm and 4.03±1.53 mm for M1 and M2, respectively. The VD measurements of M2 were significantly higher in female patients than in male patients. Conclusions: Type 3 was the most frequent anatomical relationship in the maxillary molars, and showed the lowest alveolar bone height. This information will help clinicians to prevent complications related to the maxillary sinus during maxillary molar treatment and to predict the available bone height for immediate implant planning.

• Journal of Periodontal and Implant Science
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• v.31 no.2
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• pp.269-276
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• 2001

The purpose of this study was to evaluate the clinical validity of multi-rooted teeth subjected to root-resection treatment. Over a period of 1-7 years, 60 root-resected molars in 59 patients were examined clinically and radiographically. All patients were p0eriodically recalled once or twice a year. Root-resections were due to periodontal, more specifically furcal bone loss or marginal bone loss,in 34 cases and extensive dental carious destruction in 10 cases. In other cases,root-resections resulted from 6 cases of root fracture, 6 cases of periodontal-endodontic combined lesion, and 1 case of endodontic problem. Root-resection was carried out on 26 maxillary molars and 34 mandibular molars. The results are as follows; 1. 14 cases(23.3%) were considered failures. 8 cases(13.3%) of them occurred within the first year(8 cases, 13.3%), 4 cases(6.7%)between 1-3 years, and 2 cases(3.3%) between 4-7 years. 2. 8 cases(13.3%) were considered failures due to periodontal reasons, 3 cases(5%) due to root fracture, 2 cases(3.3%) due to endodontic problem, and 1 case(1.7%) due to prosthetic problem. 3. 37 cases(61.7%) showed up for the recall appointments, and the percentage of failures(13.5%) was lower compared with that of all patients(23.3%). The results of the present study indicate that the prognosis of root-resected teeth is favourable if attention is paid to the selection of proper case and to achieving optimal oral hygiene and periodic check up.

• Journal of Periodontal and Implant Science
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• v.30 no.2
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• pp.241-257
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• 2000

Autogenous periosteal grafts are an attractive alternative to existing barrier membrane materials since they meet the reqiurements of an ideal material. But no histological data are available on the effectiveness of periosteal membranes in the treatment of periodontal defects. The purpose of this study was to evaluate effect of autogenous periosteal graft on periodontal regeneration histologically. Class II furcation defects were surgically created on the second, third and the fourth premolars bilaterally in the mandibules of six mongrel dogs. The experimental sites were divided into three groups according to the treatment modalities; control group - surgical debridement only; Group I- autogenous periosteal membrane placement after surgical debridement; Group II-autogenous periosteal membrane placement after surgical debridement and bone grafting. The animals were sacrificed at 2, 4 and 12 weeks after periodontal surgery and the decalcified and undecalcified specimens were prepared for histological and histometrical analysis. Clinically all treated groups healed without significant problems. Under light microscope, at 2 weeks, control group showed significant apical epithelial migration and bone remodelling only below the notch area. But for the group I, II with autogenous periosteal graft, less apical migration of epithelium appeared and large amount of osteoid tissue showed above the notch area. Grafted periosteal membrane was indiscernable at 4 weeks, so periosteal membrane might be organized to surrounding tissues. Histometrically, at 4 and 12 weeks, all the test and control groups didn't show significant change of epithelial zone but new attachment level tended to be gained in the test groups than control group. These results suggest that autogenous periosteal grafts should be a good alternative for guided tissue regeneration.

• Journal of Periodontal and Implant Science
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• v.26 no.4
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• pp.799-821
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• 1996

The ultimate goal of periodontal treatment has been to facilitate regeneration of diseased periodontal tissues, destroyed by inflammatory periodontal disease. For regeneration of the periodontium to occur, all of component tissues must be restored to their original position and architecture. Growth factors which were known to promote the cellular processes, ie, proliferation, migration and matrix synthesis, have been in the spotlight of current periodontics. Platelet-derived growth factor(PDGF) stimulates collagen and non collagen protein synthesis, migration and proliferation of periodontal ligament cells. Insulin-like growth factor(IGF) has potentials to induce collagen and bone matrix synthesis so that it regulates normal bone remodeling. Application of the combination have been known to facilitate formation of bone and cementum, and to synergistically interact to promote coronal migration and proliferation of periodontal ligament cells. These two growth factors have been reported to exhibit positive effect in the periodontally diseased teeth or class m furcation defects. The aim of the present study was to test the hypothesis that PDGF-BB alone or the combination of PDGF-BB and IGF-I can predictably enhance regeneration of the periodontium in the dehiscence defect. Following the resection of premolars, roots were embedded. After 12 weeks of healing period, standardized experimental $4{\times}4mm$ dehiscence defects were created on the mid-facial of the premolar roots in each of 4 young adult dogs. In control group, only methylcellulose gel was inserted in the defects. In experimental group I and II, gel with $2{\mu}g$ of PDGF-BB or $2{\mu}g$ of PDGF-BB and $1{\mu}g$ of IGF-I was inserted in the defects, respectively. At 8 weeks postsurgery, the dogs were sacrificed. The results were observed histologically and analyzed histomorphometrically.The results of this study were as follws. 1. The new cementum formation was $1.26{\pm}0.69mm$ in the control group, $1.80{\pm}0.84mm$ in the experimental group I, $1.93{\pm}0.51mm$ in the experimental group II. The experimental group III, the experimental group I, the control group were in the order of cementum formation without statistically significant differences between control and all experimental groups. 2. The new bone formation was $1.00{\pm}0.53mm$ in the control group, $1.53{\pm}0.63mm$ in the experimental group I, $l.33{\pm}0.45mm$ in the experimental group II. The experimental group I, the experimental group II, the control group were in the order of bone formation without statistically significant differences between control and all experimental groups. 3. The root resorption was $1.12{\pm}0.64mm$ in the control group, $1.34{\pm}0.73mm$ in the experimental group I, $0.79{\pm}0.59mm$ in the experimental group II without statistically significant differences between control and all experimental groups. These results suggested that the use of PDGF-BB alone or PDGF-BB and IGF-I in the dehiscence defects might facilitate periodontal regeneration in some degree, but has not shown statistically significant results.