• Imaging Science in Dentistry
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• v.39 no.1
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• pp.41-49
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• 2009

Purpose: To detect the progression of experimentally induced periapical lesions on periapical radiograph and cone beam computed tomograph (CBCT) by quantitative analysis. Materials and Methods: After the removal of coronal pulps from premolars of two Beagle dogs, the root canals of premolars were exposed to oral environment during one week and then sealed for 70 days. Digital periapical radiographs and CBCTs were taken at baseline and every 7 days for 77 days after pulp exposure. We examined occurrence and areas of periapical bone resorption. Three comparative groups of CBCT radiographs were prepared by average projection of thin slabs with different bucco-lingual thicknesses (0.1, 3.0, and 8.0 mm) using a 3D visualization software. Radiographic densities were compensated by image normalization. Digital images were processed with mathematical morphology operations. The radiographic density and morphological features of periapical lesions were compared among three groups of CBCT in different time points. Results: In the CBCT group with 0.1 mm thickness, radiographic density (p<0.05) and trabecular bone area (p<0.01) were significantly decreased at the fifth week. However, in the CBCT groups with 3 mm and 8 mm thickness and periapical radiographs, none of densitometric and morphological features showed any significant differences in different time points. Radiographic density of periapical lesion showed increasing tendency at the eleventh week after pulp exposure. Conclusion: Radiographic detection of periapical lesions was possible at the fifth week after pulp contamination by quantitative method and was affected by buccolingual bone thickness.

• Restorative Dentistry and Endodontics
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• v.25 no.2
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• pp.193-201
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• 2000

Prostaglandins (PGs) and Leukotrienes (LTs) have been implicated in the genesis of pulpal and periapical inflammation. In this study, the relationships among $PGE_2$, 6-keto-PG $F_1{\alpha}$ (a stable metabolite of $PGI_2$) and $LTB_4$ concentrations in inflamed pulp and periapical lesions were discussed. Pulp tissue were obtained in routine endodontic treatment and periapical lesions in periapical surgery after clinical diagnoses were made. These specimens were divided into four groups as normal pulp group (Control group), acute pulpitis group, chronic pulpitis group, and periapical lesion group. Pulp tissue and periapical lesions were stored in liquid nitrogen. The concentration of $PGE_2$, $PGI_2$ and $LTB_4$ were measured with ELISA. The data were analyzed by one-way ANOVA. Significantly higher levels of $PGE_2$, 6-keto-PG $F_1{\alpha}$ a and $LTB_4$ were found in acute pulpitis group than chronic pulpitis group and periapical lesion group(p<0.05). Periapical lesion group showed significantly higher mean concentrations of $PGE_2$ and $LTB_4$ than chronic pulpitis group. In control and chronic pulpitis group, significant higher levels of $PGI_2$ than $PGE_2$ and $LTB_4$ were found. These results suggested that the high levels of $PGE_2$ and $LTB_4$ in periapical lesions may be due to rich endothelium., fibroblast and lymphocyte known as the main producers of $PGE_2$ and $LTB_4$. $PGI_2$ may be thought to one of the most abundant PGs in normal pulp tissue.

• Imaging Science in Dentistry
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• v.52 no.2
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• pp.209-217
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• 2022

Purpose: The aim of this study was, firstly, to determine the concordance of ultrasonographic and histopathological diagnoses in patients in whom apical resection was already indicated. Secondly, this study aimed to determine whether lesions were periapical granulomas or cysts, and to compare them after root canal treatment using ultrasonography and periapical radiographs. Materials and Methods: In the first stage of the study, ultrasonographic and histopathologic diagnoses of 10 lesions were compared. Secondly, the periapical radiographs and ultrasonographic images of 44 lesions were measured. The presence of internal vascularity was determined by ultrasonographic color and power Doppler modes. Follow-up examinations of healing after root canal treatment were performed using ultrasonography and periapical radiographs, and these modalities were compared. Results: In the periapical granuloma and cyst groups, the measurement values decreased for all variables. There was no significant difference in the dimensional changes of lesions between the 2 groups, and ultrasonography and periapical radiographs were compatible. The pre-diagnoses were compared with histopathological diagnoses and were found to be compatible. Conclusion: The ultrasonographic color and power Doppler techniques could be an effective method for diagnosing periapical lesions as cysts or granulomas. After root canal treatment of granulomas and cysts, the dimensional shrinkage and healing patterns appear to be similar. Ultrasonography and periapical radiographs were consistent in terms of dimensional comparisons, and ultrasonography may be an alternative method for follow-up of the healing of periapical lesions.

• Restorative Dentistry and Endodontics
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• v.47 no.1
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• pp.12.1-12.11
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• 2022

Objectives: This pilot study aimed to establish the interrelationship between collagen and mast cells in periapical granulomas and periapical cysts. Materials and Methods: An observational cross-sectional study was conducted on the paraffin-embedded tissue sections of 68 specimens (34 periapical granulomas and 34 periapical cysts). The specimens were stained with picrosirius to observe collagen fiber birefringence and anti-tryptase antibody to evaluate the mast cell count immunohistochemically. The mean number and birefringence of collagen fibers, as well as the mean number of mast cells (total, granulated, and degranulated), and the mean inflammatory cell density were calculated. The data obtained were analyzed using the Kruskal Wallis test, Mann Whitney U test, and Spearman correlation test (p < 0.05). Results: The mean number of thick collagen fibers was higher in periapical cysts, while that of thin fibers was higher in granulomas (p = 0.00). Cysts emitted orange-yellow to red birefringence, whereas periapical granulomas had predominantly green fibers (p = 0.00). The mean inflammatory cell density was comparable in all groups (p = 0.129). The number of total, degranulated, and granulated mast cells exhibited significant results (p = 0.00) in both groups. Thick cyst fibers showed significant inverse correlations with inflammation and degranulated mast cells (p = 0.041, 0.04 respectively). Conclusions: Mast cells and inflammatory cells influenced the nature of collagen fiber formation and its birefringence. This finding may assist in the prediction of the nature, pathogenesis, and biological behavior of periapical lesions.

• The Journal of the Korean dental association
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• v.13 no.6
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• pp.529-531
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• 1975

This observation was carried out to investigate the phosphatase activity and the calcium contents of periapical granuloma in patients of both sex and different age. The results were as follows : 1. Acid phosphatase activity was considerably increased with bone absorption. 2. Alkaline phosphatase activity was also remarkably increased in periapical granuloma. 3. In case of periapical granuloma, differences of phosphatase activity by age and sex were not observed. 4. Calcium contents in periapical granuloma was of very small quantity, showing remarkable decrease when compared with the normal bone tissue.

• Restorative Dentistry and Endodontics
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• v.15 no.2
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• pp.58-76
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• 1990

This study was designed to elucidate the distribution of the immunoglobulins in the experimentally induced rat periapical lesions. The pulp exposure was performed in 80 molars from 40 rats and the animals were sacrificed at 15, 30, 60 and 90 days after the operation and examined and radiographed. Of the 80 samples, 56 samples were routinely sectioned ($4-6{\mu}$ in thickness) and stained with Hematoxylin-Eosin for the light microscopic examination and 50 samples were stained with toluidin blue for mast cells and 50 samples were stained using the Avidin-Biotin horseradish peroxidase for detecting the presence of Ig A, Ig E, Ig M and Ig G containing cells. The following results were obtained : 1. The periapical lesions could be observed in all of 80 teeth by radiogragh (100%) and the periapical lesions were detected in 50 samples of 51 samples by light microscopy (98%). The size of lesions increased with time lapse both by radiograph and by light microscopy(p<0.05). 2. Of the 50 samples, 19 samples were diagnosed as periapical abscesses, 18 as periapical granulomas, 10 as fibrous scar tissues and 3 cysts. 3. After pulp exposure, periapical granulomas were developed mostly in the 15 day group, with time lapse periapical abscesses and fibrous scar tissues increased. 4. In the 50 periapical lesions, the numbers of Ig G containing cell (57.2%) were prominent and the percentage of Ig A, Ig E and Ig M containing cells were 16.4%, 14.7% and 11.8% respectively. The numbers of all classes of immunoglobulin containing cell were highest in the periapical granulomas and lowest in the cysts(p<0.05). 5. The number of the mast cell and immunoglobulin containing cells decreased generally with time lapse after the pulp exposure and Ig A, Ig E, Ig M and Ig G containing cells and mast cells had the high correlation one another(>0.6).

• Imaging Science in Dentistry
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• v.35 no.1
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• pp.41-46
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• 2005

Purpose : The purpose of this study was to investigate whether the fractal dimension and radiographic image brightness of periapical radiograph were useful in predicting osteoporosis. Materials and Methods : Ninety-two postmenopausal women were classified as normal, osteopenia and osteoporosis group according to the bone mineral density of lumbar vertebrae and periapical radiographs of both mandibular molar areas were taken. The ROIs of 358 areas were selected at periapical and interdental areas and fractal dimension and radiographic image brightness were measured. Results : The fractal dimension in normal group was significantly higher than that in osteoporosis group at periapical ROI (P < 0.05). The radiographic image brightness in normal group was higher than that in osteopenia and osteoporosis group. There was significant difference not only between normal and osteopenia group (P < 0.05) but also within osteopenia and osteoporosis group (P< 0.01) at periapical ROI. Significant difference was observed not only between normal and osteopenia group but also between normal and osteoporosis group at interdental ROI (P< 0.01). Positive linear relationship was weakly shown at Pearson correlation analysis between fractal dimension and radiographic image brightness. BMD significantly correlated with fractal dimension at periapical ROI (P< 0.01), and BMD and radiographic image brightness significantly correlated at both periapical and interdental ROIs (P< 0.01). Conclusion : This study suggests that the fractal dimension and radiographic image brightness of periapical ROI may predict BMD. (Korean J Oral Maxillofac Radiol 2005: 35 : 41-6)

• Imaging Science in Dentistry
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• v.30 no.1
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• pp.49-54
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• 2000

Purpose : To compare the diagnostic performance of clinical and radiologic examination for the interproximal caries on intraoral periapical radiographs and to evaluate the value of periapical radiographs. Methods: One hundred seven dental patients were examined clinically, with a mouth mirror and an explorer, by a dentist at the department of oral medicine, and the presence or absence of interproximal caries lesion was recorded. The patients were prescribed one or more dental periapical radiographs. Radiographs were assessed for the presence of interproximal caries by three oral and maxillofacial radiologists independantly. Two thousand sixty interproximal surfaces were included in this study. The diagnostic accuracies of clinical and radiologic examinations for interproximal caries were calculated. To assess the degree of agreement between clinical and radiologic examinations, Cohen's coefficient of agreement was computed. Results: The specificity of clinical and radiologic examination was 0.991, 0.997 and the sensitivity was 0.279, 0.985 respectively. The diagnostic accuracy of radiologic examination was statistically significantly higher than that of clinical examination (P<0.05). Cohen's kappa value of clinical and radiologic examination was 0.335, 0.942 respectively. These results suggested that clinical examination show only fair agreement, whereas radiologic examination show perfect agreement. Conclusion: The diagnositic performance of the dental periapical radiographs on interproximal caries were higher than that of clinical examination, thus this study showed the validity of periapical radiographs for detecting interproximal caries lesion without bitewing radiograph.

• Imaging Science in Dentistry
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• v.38 no.3
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• pp.147-151
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• 2008

Purpose : The purpose of this study was to investigate whether fractal analysis of periapical and panoramic radiographs was useful in predicting osteoporosis risk. Materials and Methods : 37 postmenoposal women between the age of 42 and 79 were classified as normal and osteoporosis group according to the bone mineral density of lumbar vertebrae and periapical and panoramic radio-graphs were taken. Fractal dimensions at periapical areas of mandibular first molars were calculated to differentiate the two groups. Results : The mean fractal dimensions of normal group on periapical and panoramic radiographs were $1.413{\pm}0.079$, $1.517{\pm}0.071$ each. The mean fractal dimensions of osteoporotic group on periapical and panoramic radiographs were $1.498{\pm}0.086$, $1.388{\pm}0.083$ each. The mean fractal dimension from peripaical radiographs of osteoporotic group was statistically significantly higher than that of normal group. The mean fractal dimension from panoramic radiographs of osteoporotic group was statistically significantly lower than that of normal group. Conclusion : Fractal analysis using periapical and panoramic radiographs was useful in predicting osteoporosis.

• Imaging Science in Dentistry
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• v.33 no.2
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• pp.71-77
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• 2003

Purpose : To evaluate and compare the efficacy of digital radiographic images in the detection of bone loss at the bifurcation area of the mandibular first molar with traditional film-based periapical radiographs, Materials and Methods : One dried human mandible with minimal periodontal bone loss around the first molar was selected and an artificial alveolar bone defect at the bifurcation area was serially prepared over 18 steps. Images were taken using a direct CCD-based system and with F-speed periapical films. The images were evaluated by seven interpreters (3 radiologists, 3 periodontologists, and 1 general dentist) using a 5-point confidence rating scale. Results : The readability of both periapical radiographs and digital image increased as the size of the artificial lesion and exposure time increased (p < 0.05). Periapical radiographs offered greater readability of smaller bone defects than digital images, and the coefficient of variation of mean score between periapical radiographs and digital images showed a significant difference. Conclusion : The experimental results indicate that a significant difference in the coefficient of variation of mean score exists between periapical radiographs and digital images, and that traditional film-based periapical images offer greater readability of smaller bone defects than digital images can presently offer.