Jeng-Huey Chen

The Combined Occluding Effects of Fluoride-Containing Dentin Desensitizer and Nd-YAG Laser Irradiation on Human Dentinal Tubules: An in Vitro Study

The purpose of the present study was to evaluate the combined occluding effects of fluoride‐containing dentin desensitizer and neodymium:yttrium aluminum garnet (Nd‐YAG) laser irradiation on human dentinal tubules. All six of the groups of dentin samples (A‐F) included in this study received applications of fluoride‐containing dentin desensitizer. Groups B, D, and F also received Nd‐YAG laser irradiation. Groups A and B served as controls, to allow observations of the occluding effects on the dentinal tubules before and after Nd‐YAG laser irradiation. Groups C and D were treated with 0.5 M vitamin C solution, whereas groups E and F underwent brushing with an electric toothbrush. Scanning electron microscopy (SEM) revealed that the fluoridated dentinal tubule‐occluding agent (FDTOA) formed a fine crystalline deposit on the dentin surface. After soaking in 0.5 M vitamin C solution for 3 hours, the crystalline deposit of the FDTOA was completely dissolved. Furthermore, brushing of the teeth 3,600 times removed most of the occluding agent. When the application of FDTOA was combined with Nd‐YAG laser irradiation, the dentin melted and then recrystallized. The occluding agent was thus ‘burned into’ the dentinal tubules, and could neither be dissolved by vitamin C solution nor removed by brushing. Therefore, we concluded that the FDTOA combined with Nd‐YAG laser irradiation burns the occluding agent into the dentinal tubules, thereby resisting the effects of an acidic diet and brushing, and increasing the duration of the desensitizing effect.

Peripheral Odontogenic Fibroma in a Taiwan Chinese Population: A Retrospective Analysis

A retrospective analysis of 25 cases of peripheral odontogenic fibroma (World Health Organization‐type) (PODF [WHO‐type]) in a Taiwan Chinese population was performed at a single institution. The clinical findings, which included a wide age distribution, a female preponderance and no racial predilection, were consistent with those of previous case series reports; however, a slight preference for location in the maxilla was found in the current case series. It is noteworthy that one particularly sizable lesion was identified in a 30‐year‐old Chinese female who presented with a swollen mass in the right mandible that had been present for about 2 years. Intraoral examination revealed an exophytic firm mass that measured 4.5 × 4 cm, located over the right mandibular edentulous ridge from the second premolar to the second molar area. Both panoramic radiography and computerized tomography revealed multiple radiopacities within the tumor. In conclusion, the analysis of clinical data in the current case series of PODFs (WHO‐type) occurring in Taiwan Chinese mostly corroborates other reports; however, an unusually large mandible lesion was noted, indicative of the apparent size that such tumors can reach unless they are surgically removed at an early stage.

Long-term sequential receptor activator of NF-κB ligand (RANKL) and osteoprotegrin (OPG) expression in lipopolysaccharide-induced rat periapical lesions

BACKGROUND Long-term sequential expression of receptor activator of NF-κB ligand (RANKL) and osteoprotegrin (OPG) in lipopolysaccharide (LPS)-induced rat periapical lesions has not been studied. MATERIALS   Seventy-two 4-week-old Wistar rats were divided into eight experimental groups and one control group (eight animals in each). METHODS Lipopolysaccharide-induced periapical lesions were produced in rats by occlusal exposure of the pulp of their lower first molars in all experimental groups but not the control group. The extent of periapical destruction was measured by radiographic imaging. RANKL and OPG mRNA were measured in all tissue sections containing the periapical lesions as well as the control group every week from week 1 to week 8 by real-time quantitative reverse transcription polymerase chain reaction. RANKL and OPG protein were determined by immunohistochemistry. Osteoclasts were identified by enzyme histochemistry. RESULTS The sequential changes in the mRNA and protein expression of RANKL and OPG were largely compatible with the occurrence of osteoclasts histologically and enzymes histochemically, as well as the mean areas of the periapical lesions radiographically during long-term observation of the LPS-induced rat periapical lesions. CONCLUSION This study may be the first to demonstrate the long-term RANKL and OPG expression every week from week 1 to week 8 using LPS to produce periapical infection in a Wistar rat model. The long-term findings of high expressions of RANKL and OPG further extend the potential application of the Wistar rat model for future experimental trials using RANKL inhibitor to evaluate the treatment outcome for LPS-induced rat periapical lesions.

Clinicopathological analysis of 232 radicular cysts of the jawbone in a population of southern Taiwanese patients

This retrospective study aimed to evaluate the clinicopathological features of 232 cases of radicular cyst (January 2001–December 2016) submitted for histopathological examination to Department of Oral Pathology by endodontists in our institution. Demographic data including age, gender, affected site, involved tooth, and histopathological features, were reviewed. The study population comprised 133 females (57.3%) and 99 males (42.7%), with a mean age of 40.5 years and an age range of 13–78 years. Two‐hundred and one cysts occurred in the maxilla (86.7%) and 31 in the mandible (13.3%). Most cases involved the anterior teeth of the maxilla (67.2%). The most frequently‐involved tooth was the maxillary lateral incisor (50.5%). In most cases (228 cases; 98.3%), the cyst was lined with nonkeratinized stratified squamous epithelium, with two cases containing epithelial lining of the mucoepidermoid epithelium (0.9%) and respiratory epithelium (0.9%), respectively. One case (0.4%) revealed epithelial dysplasia of the epithelial lining. Hyaline body was seen in two cases (0.9%), and Rushton body was noted in seven cases (3.0%). Odontogenic epithelial rest was noted in one case (0.4%). Cholesterol clefts (54 cases; 23.3%), foamy histiocytes (72 cases; 31.0%), hemosiderins (57 cases; 24.6%), dystrophic calcifications (94 cases; 40.5%), foreign bodies (44 cases; 19.0%), and bacterial colonies (22 cases; 9.5%) were also observed. Fifty‐three cases (22.8%) showed a mixed acute and chronic inflammatory infiltrate, whereas chronic inflammatory infiltrate only was noted in 179 cases (77.2%). In summary, the current findings provide a valuable source for clinicopathological reference concerning radicular cysts of the jawbone.

Comparison of Two Heat-pressed All-ceramic Crown Systems

There is increasing demand for all‐ceramic crowns to improve esthetics and avoid the intraoral use of metal. There are several ways to fabricate all‐ceramic prostheses. The heat‐press method is easily handled, creates less porosity than the conventional powder slurry method, produces consistent quality, and avoids firing shrinkage. Each of the popular brands of heat‐press ceramics has its own heat‐press furnace. The purposes of this study were to determine whether it was possible to use one heat‐press furnace to make different all‐ceramic prostheses, and to compare the fit and hardness of two commercial heat‐press all‐ceramic systems made using the staining technique. Ceramic ingots were analyzed by X‐ray diffraction analysis before heat press. Finesse® All‐Ceramic and OPC 3G® specimens were both heat‐pressed using a porcelain pressing furnace designed for Finesse®. Mesio‐occluso‐distal inlays were cemented to the metal die with temporary cement. Marginal accuracy was measured using a three‐dimensional coordinate measuring machine. Vickers hardness was measured using a microhardness tester. X‐ray diffraction analysis of the ceramic ingots showed that the main peak position for Finesse® was leucite (KAlSi2O6) and for OPC 3G® was lithium disilicate (Li2Si2O5). The marginal gap for Finesse® was statistically lower than that for OPC 3G® (62.5 ± 15.5 vs 99.4 ± 11.6 mm; p < 0.05). There was no statistically significant difference in hardness between Finesse® and OPC 3G® (613.8 ± 49.2 vs 660.0 ± 34.0 kgf/mm2; p > 0.05). The marginal gaps for Finesse® and OPC 3G® were clinically acceptable. Therefore, it is possible to use one heat‐press furnace to cast different all‐ceramic systems.