Fu-Hsiung Chuang

Immunohistochemical expression of RANKL, RANK, and OPG in human oral squamous cell carcinoma

BACKGROUND The mechanism of oral squamous cell carcinoma (SCC) invading jawbone remains controversial. Interactions between receptor activator of NF-kappaB (RANK) and its ligand (RANKL) are required for osteoclastogenesis. The binding of RANK and RANKL induces differentiation of osteoclasts, leading to bony destruction. Osteoprotegerin (OPG), a decoy receptor for RANKL, also binds to RANKL by competing with RANK, and this could protect against osseous destruction. MATERIALS AND METHODS Immunoexpression of RANKL, RANK, and OPG in 25 cases of human buccal SCCs without bony invasion and 15 cases of gingival SCCs with mandibular bony invasion was investigated. Normal oral mucosa from five individuals without betel-quid chewing or cigarette smoking was used as a control. The scores are designated as percentage of positive staining x intensity of staining for each section. RESULTS Strong cytoplasmic staining of RANKL proteins is detected in cancer cells of both buccal and gingival SCCs. The same protein is identified in cytoplasm of osteoclasts for all cases involving bony invasion. Strong cytoplasmic staining of RANKL is confined to basal layer for all normal mucosa. A similar staining pattern is noted for RANK protein in all buccal and gingival SCCs. An absence of staining of RANK protein is noted for all normal tissues. Weak to negative cytoplasmic stained OPG protein is present in all buccal and gingival SCCs, but is absent in all normal tissues. CONCLUSION These findings suggest the potential value of the RANK/RANKL/OPG pathway as biomarkers in human oral SCCs.

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.

Caldwell-Luc procedure for retrieval of displaced root in the maxillary sinus

OBJECTIVE The aim of this study was to describe the standard diagnostic procedure and the application of the Caldwell-Luc approach for the retrieval of a displaced root from the maxillary sinus and to share our experience in treating this complication. STUDY DESIGN Twenty-four patients with a fractured root accidentally displaced into the maxillary sinus were referred by general dentists to our department from 2005 to 2008. All were managed by a standardized diagnostic procedure and a Caldwell-Luc approach. We recorded the age of each patient, the gender, the tooth, the size of root fragment, the type of displacement the delay between displacement and retrieval, the length of operating time, and any complications. RESULTS Over a 4-year period, we treated 24 patients, 14 being male and 10 female. Ages ranged from 14 to 55 years (average 26.4). The commonest tooth involved was the maxillary first molar; the length of the root fragments ranged from 3 to 7 mm. Seventeen of these roots were mobile and 7 fixed (4 being located between the sinus membrane and the bone and 3 immobilized by the sinus membrane. Twenty-three of the operations were completed in 30 minutes, and only 2 patients had a temporary complication of sinusitis. No infraorbital paresthesia occurred. CONCLUSIONS The standardized diagnostic procedure and Caldwell-Luc approach for the retrieval of a displaced root form the maxillary sinus is a safe, simple, and fast method with minimal complications.

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.

Facial Cellulitis Arising from Dens Evaginatus: A Case Report

Dens evaginatus is a developmental anomaly that produces a tubercle on the occlusal surface of a tooth. It is found most frequently in the mandibular premolars. The occlusal tubercle easily causes occlusal interferences. Attrition or fracture of the tubercle can lead to pulpitis, pulp necrosis, periapical pathosis, and periapical infection. This case report illustrates the treatment of facial cellulitis arising from dens evaginatus with open apex. Calcium hydroxide was used for the apexification procedure. One year after canal obturation, radiography revealed no apical pathosis and the apical seal was evident.

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.

Occurrence of ameloblastoma in a patient with nasopharyngeal carcinoma after treatment by irradiation

Ameloblastoma is the most common clinically significant epithelial odontogenic tumor, and is considered a benign but locally aggressive tumor of the craniofacial region. We present the case history of a 46-year-old male patient who had a nasopharyngeal carcinoma (NPC) treated by irradiation, which was complicated by the occurrence of an ameloblastoma. Following a review of the English language literature, this case history was identified as being the first report, to our knowledge, of the occurrence of ameloblastoma in a patient who had been irradiated for an NPC. This case report highlights the importance of regular dental care for a patient who had an NPC and was treated with radiation therapy.