Surawut Pongsiriwet

Diagnostic performance of cone-beam computed tomography on detection of mechanically-created artificial secondary caries

Purpose The aim of this study was to compare the diagnostic accuracy of cone-beam computed tomography (CBCT) images and bitewing images in detection of secondary caries. Materials and Methods One hundred and twenty proximal slots of Class II cavities were randomly prepared on human premolar and molar teeth, and restored with amalgam (n=60) and composite resin (n=60). Then, artificial secondary caries lesions were randomly created using round steel No. 4 bur. The teeth were radiographed with a conventional bitewing technique and two CBCT systems; Pax-500ECT and Promax 3D. All images were evaluated by five observers. The area under the receiver operating characteristic (ROC) curve (Az) was used to evaluate the diagnostic accuracy. Significant difference was tested using the Friedman test (p value<0.05). Results The mean Az values for bitewing, Pax-500ECT, and Promax 3D imaging systems were 0.882, 0.995, and 0.978, respectively. Significant differences were found between the two CBCT systems and film (p=0.007). For CBCT systems, the axial plane showed the greatest Az value. Conclusion Based on the design of this study, CBCT images were better than bitewing radiographs in detection of secondary caries.

A multicenter study of oral lichen planus in Thai patients

AIM Oral lichen planus is an oral mucosal disease that affects middle-aged patients. The characteristics of oral lichen planus in Thai patients from a multicenter were studied. METHODS Data of 533 patients from the oral medicine clinics at Chulalongkorn and Mahidol (central Thailand), Chiang Mai (northern Thailand), and Khon Kaen (northeastern Thailand) universities during 2002-2007 were analyzed. The diagnosis of patients with oral lichen planus was clinically and/or histopathologically confirmed. RESULTS There was a greater number of female patients than males (4:1). There were significant differences in age, sex, and some systemic diseases among the oral lichen planus patients from the three centers. Burning sensation was the most common symptom (72.9%), followed by pain (26.5%), roughness (6.4%), and then no other symptoms (7.9%). The most common site of lesions was found at the buccal mucosa (87.1%). Atrophic oral lichen planus was common in Thai patients. There were significant differences in the types of oral lichen planus, including reticular, atrophic, and ulcerative oral lichen planus among these patients from the three centers (P = 0.000). Nine cases (1.7%) showed dysplasia, but one case (0.2%) developed squamous cell carcinoma. CONCLUSION Patients with oral lichen planus from the central, northern, and northeastern parts of Thailand presented with distinct characteristics. The malignant transformation of oral lichen planus was low in Thai patients.

Increased cyclooxygenase 2 expression in association with oral lichen planus severity

Background/purpose Although some studies have shown induction of cyclooxygenase 2 (COX-2) in oral lichen planus (OLP), an association between COX-2 upregulation and OLP clinical severity has not been investigated. Therefore, we aimed to compare COX-2 expression in OLP with that in normal oral tissues, and to determine correlations between COX-2 expression and both clinical criteria and visual analog scale (VAS) scores. Materials and methods COX-2 expression was studied in 25 OLP and 13 normal oral tissues by immunohistochemistry. Both clinical criteria and VAS scores were used to evaluate the clinical severity of OLP. The differences in COX-2 expression between OLP and normal tissues, and the correlations between COX-2 expression and clinical severity were determined by the nonparametric statistical tests. Results COX-2 expression was significantly increased in OLP epithelium when compared with normal epithelium (P < 0.001), and intense COX-2 staining in inflammatory infiltrates was observed in the OLP lamina propria. COX-2 expression in OLP epithelium and inflammatory infiltrates was significantly correlated with the clinical criteria score (r = 0.428, P = 0.007, and r = 0.681, P < 0.001, respectively), whereas a significant correlation with the VAS score was observed only in OLP inflammatory infiltrates (r = 0.605, P < 0.001). Conclusion Enhanced COX-2 expression in both OLP epithelium and inflammatory infiltrates correlates well with the clinical severity. An association between VAS score and COX-2 expression in OLP inflammatory infiltrates suggests an important role of additional COX-2 expression from inflammation in causing pain in OLP patients.

Effect of coenzyme Q10 on mitochondrial respiratory proteins in trigeminal neuralgia

Abstract Trigeminal neuralgia (TN) is the neuropathic pain. Mitochondrial dysfunction, increased oxidative stress, and inflammation demonstrated in chronic pain. Carbamazepine (CBZ) is the first-line drug for TN, however, it is still insufficient. Coenzyme Q10 (CoQ10) has been used as the additional supplement for pain therapy. Nonetheless, mitochondrial respiratory proteins, oxidative stress, and inflammation in TN, and the add-on effects of CoQ10 on those defects have never been investigated. CBZ-treated TN-patients, naïve TN-patients, and control subjects were included. CBZ-treated TN-patients were randomised into two subgroups, received either CoQ10 or placebo for 2 months. Pain levels were evaluated, and peripheral blood mononuclear cells were isolated to determine the oxidative stress, mitochondrial oxidative phosphorylation (OXPHOS), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), and cytokines including TNF-α, IL-1β and IL-18 mRNA expression. Pain scales, oxidative stress, and OXPHOS levels were greater in naïve TN-patients than control, whereas the cytokine profiles were unchanged. Although pain scales were lower in CBZ-treated TN-patients than in naïve TN-patients, oxidative stress, OXPHOS, and cytokine expression profiles were not different. PGC-1α levels found to be increased in CBZ-treated TN patients when compared with the naïve group. CoQ10 supplement in CBZ-treated TN patients reduced pain scale and oxidative stress and increased antioxidants levels when compared with placebo group. However, OXPHOS, PGC-1α, and cytokines were not different between groups. These findings suggest that increased oxidative stress could be potentially involved in the pathogenesis of TN. CoQ10 supplements can reduce oxidative stress, leading to more effective pain reduction in TN patients being treated with CBZ.