Drug holiday clinical relevance verification for antiresorptive agents in medication-related osteonecrosis cases of the jaw.

Treatment strategies of medication-related osteonecrosis of the jaw (MRONJ) are controversial. Recently, surgical treatment has been reported as superior to nonsurgical treatment, but the contribution discontinued antiresorptive agent use during MRONJ treatment remains unclear. This study aimed to evaluate the efficacy of drug holidays and treatment strategies in MRONJ cases. Four-hundred and twenty-seven patients with MRONJ treated at nine hospitals from 2009 to 2017 were included in this multicenter retrospective study. Multivariate Cox regression analysis showed that the primary disease (osteoporosis or malignant tumor), diabetes, serum albumin, and treatment method (surgical or nonsurgical) were significantly correlated with the cure rate. The cumulative 1-year cure rates in the surgical and nonsurgical treatment groups were 64.7% and 18.2%, respectively. However, discontinuing antiresorptive agents did not influence the treatment outcome in the cohort overall, or in 230 patients after performing propensity score matching among the discontinuation and continuation groups. When stratifying by treatment method, antiresorptive agent discontinuation significantly increased the cure rate in patients with osteoporosis who underwent nonsurgical treatment. In patients with malignant tumors undergoing nonsurgical therapy, discontinuing the antiresorptive agent was associated with a better treatment outcome, but not with statistical significance. In contrast, drug holidays showed no effect on improving outcomes in patients with both osteoporosis and malignant tumors who underwent surgical therapy. Thus, regardless of the primary disease, discontinuing antiresorptive agents during treatment for MRONJ may not be necessary and may be helpful in some cases. Future prospective trials should examine this question further.

Prevalence of and risk factors for postoperative hemorrhage after lower third molar extraction on warfarin therapy: a multicenter retrospective study in Japan.

Postoperative hemorrhage after tooth extraction is a critical and clinically important issue for clinicians and patients receiving anticoagulants. The purpose of the present study was to investigate the prevalence of and risk factors for postoperative hemorrhage after lower third molar extraction in Japanese patients receiving warfarin therapy. A total of 142 patients who underwent lower third molar extraction between January 2010 and December 2016 were included, and their medical records were retrospectively reviewed. The prevalence of and risk factors for postoperative hemorrhage were investigated. The prevalence of postoperative hemorrhage after lower third molar extraction was significantly higher in patients receiving warfarin than in healthy subjects (21.8% vs 0.7%, P < 0.001). The cutoff value for PT-INR was 2.11 based on a receiver-operating characteristic analysis. A multivariate analysis indicated that an elevated PT-INR value [hazard ratio (HR) 3.798, 95% confidence interval (CI) 1.400-10.467, P < 0.01], preoperative antibiotic administration (HR 4.434, 95% CI 1.591-14.775, P < 0.01), difficulties with intraoperative hemostasis (HR 16.298, 95% CI 2.986-110.677, P < 0.01), and higher serum creatinine levels (HR 7.465, 95% CI 1.616-39.576, P < 0.05) are significant predictors of postoperative hemorrhage after lower third molar extraction. Multivariate correlations were observed between risk factors including an elevated PT-INR value, preoperative antibiotic administration, and higher serum creatinine levels, and postoperative hemorrhage after lower third molar extraction in patients receiving warfarin therapy. Clinicians need to consider these risk factors for postoperative hemorrhage after the lower third molar extraction and monitor PT-INR in patients receiving warfarin therapy.

Comparison of Subjective and Objective Assessments of Neurosensory Function after Lingual Nerve Repair.

OBJECTIVE: Mandibular third molar extractions are important in oral maxillofacial surgery. Damage to the lingual nerves, although rare, is a possible complication. There are reports of postoperative recovery after lingual nerve repair, but few reports have compared subjective and objective assessments of neurosensory function. Therefore, this study aims to compare subjective and objective assessments of neurosensory function after lingual nerve repair. SUBJECTS AND METHODS: This retrospective cohort study comprised 52 patients with lingual nerve anesthesia after third molar extraction at the Department of Oral and Maxillofacial Surgery, Wakayama Medical University Hospital, Wakayama, Japan, between December 2008 and December 2015. We recorded pre- and postoperative (6 months and 12 months) neurosensory examinations. RESULTS: Patient's subjective assessments of neurosensory function suggested improvement between the preoperative period and 12 months postoperation, although this difference was not significant. Objective assessment based on examination and testing, on the other hand, showed a significant difference in improvement (p < 0.05). CONCLUSIONS: There was no evidence that improvement of subjective preoperative and postoperative assessments was significantly associated with improvement of objective neurosensory assessments after lingual nerve repair. Overall physical condition and background were thought to affect subjective evaluation. Subjective assessment is important in conjunction with objective evaluation because it may reveal dysesthesia that would otherwise be missed. In the future, we will examine those cases in whom subjective assessments showed no improvement although objective assessments showed improvement.

Outcome following lingual nerve repair with vein graft cuff: a preliminary report.

PURPOSE: The object of this study was to assess the effects of an inside-out vein graft as a cuff after direct suture on human lingual nerve regeneration and recovery after iatrogenic lingual nerve injury. PATIENTS AND METHODS: Ten patients with unilateral lingual nerve anesthesia as a complication of iatrogenic injury after third molar extraction underwent microneurosurgical procedures for the injured lingual nerve under general anesthesia. The patients were randomized into 2 groups. In group A, after removing the neuromas and peripheral scars surrounding the torn nerves, the 2 nerve ends were sutured without tension. In group B, after the same procedure, including the same suturing procedure, an inside-out vein graft was placed as a cuff after the direct suture. Each group was followed at least once every 6 months for 1 year after the procedure. Postoperative outcomes were evaluated using the Pogrel criteria, the Sunderland grade, and the British Medical Research Council Scale (MRCS). RESULTS: There were no particular differences between groups A and B at 6 and 12 months after the operation. However, based on the MRCS criteria, there was a clearly better result in group B than in group A at 6 and 12 months after the operation, and the recovery of gustatory sensation tended to be better in group B than in group A 1 year after the operation. CONCLUSION: This inside-out vein graft as a cuff after direct suturing may facilitate faster lingual nerve regeneration than the traditional direct suture approach. The inside-out vein graft as a cuff may provide the advantages of preventing axonal escape at the suture lines, minimizing nerve entrapment, and preventing neuroma formation in the space between the sutured nerves.

Application of Tinel's test combed with clinical neurosensory test distinguishes spontaneous healing of lingual nerve neuropathy after mandibular third molar extraction.

BACKGROUND: Extraction of the mandibular third molar, the most frequent and important surgical procedure in the clinical practice of oral surgery, is associated with the risk of injury of the lingual nerve. Neuropathy of the lingual nerve poses diagnostic challenges regarding the transient or permanent nature of the injury. No consensus or criteria have been established regarding the diagnosis of lingual nerve neuropathy. We applied both Tinel's test and clinical neurosensory testing together, which can be easily used at the bedside in the early stages of injury. Therefore, we propose a new method to differentiate between lesions with the ability to heal spontaneously and those that cannot heal without surgery. RESULTS: Thirty-three patients (29 women,  4 men; mean age, 35.5 years) were included in this study. For all patients, the median interval between nerve injury and initial examination was 1.6 months and that between nerve injury and the second examination before determining the need for surgical management was 4.5 months. The patients were assigned to either group A or B. The spontaneous healing group (group A, n = 10) revealed a tendency for recovery within 6 months after tooth extraction. In this group, although there were individual differences in the degree of recovery, a remarkable tendency for recovery was observed based on clinical neurosensory testing in all cases. None of the patients were diagnosed with allodynia. In seven cases, the Tinel test result was negative at the first inspection, and in three cases, the result changed to negative at the second inspection. Conversely, in group B(n = 23), no recovery trend was observed with regard to clinical neurosensory testing, and nine patients had allodynia. Further, the Tinel test result was positive for all patients in both examinations. CONCLUSIONS: Our findings indicate that in case of transient lingual nerve paralysis, clinical neurosensory testing findings deteriorate immediately after tooth extraction and gradually recover, while Tinel's test shows a negative result. Using Tinel's test and clinical neurosensory testing together enabled early and easy identification of the severity of the lingual nerve disorder and of lesions that would heal spontaneously without surgical management.

Usefulness of myofascial flap without skin in contemporary oral and maxillofacial reconstruction.

PURPOSE: Pedicle myofascial graft should be considered in contemporary oral and maxillofacial reconstruction for the following reasons: 1) the pedicle myofascial unit is reliable and easily handled; 2) on the grafted myofascia in the oral cavity, the mucosa regenerates naturally with regard to suppleness and surface characteristics; and 3) vascularized myofascial coverage of tissues or materials is useful in some clinical situations. The purpose of this retrospective study was to evaluate the usefulness of this graft material. PATIENTS AND METHODS: Using myofascial flaps from the pectoralis major muscle in 15 patients and from the platysma muscle in 11 patients, several types of reconstructive procedures were conducted in the Department of Oral and Maxillofacial Surgery, Wakayama Medical University. RESULTS: Myofascial tissue was used to cover the surgical defect and for regeneration of oral mucosa (24 patients), to prevent exposure of the mandibular reconstruction plate (4 patients), for prevention of wound breakdown and secondary infection in the oral cavity (2 patients), for vascularized coverage of free grafted autologous bone (2 patients), and for protection of large vessels after radical neck dissection (9 patients). Although partial flap necrosis or wound dehiscence was noticed in 3 patients with a platysma-myofascial graft, the healing process of all patients was favorable and required no additional operations. This procedure is most suitable for the reconstruction of small to medium-sized soft tissue defects in the oral cavity, because it induces the formation of nearly normal mucosa through epithelial regeneration without clear scar formation. CONCLUSIONS: Myofascial flap is a useful option in certain oral and maxillofacial reconstruction cases in which mucosal regeneration and/or vascularized soft tissue coverage are required.

The effects of perioperative oral management on perioperative serum albumin levels in patients treated surgically under general anesthesia: A multicenter retrospective analysis in Japan.

ABSTRACT: The purpose of the present study was to investigate the efficacy of perioperative oral managements (POMs) on perioperative nutritional conditions in patients undergoing surgery with general anesthesia. Medical records were retrospectively reviewed and the effects of POMs were investigated based on a large number of cases using a multicenter analysis. The profile of serum albumin levels was assessed and compared between patients with and without POMs using the multivariate analysis. Seventeen Eleven thousand and one hundred sixty patients (4,873 males and 6,287 females) were reviewed. Of these, 2710 patients (24.3%) had undergone POMs. The results of a multivariate analysis revealed the significant positive effect of POMs on perioperative serum albumin level (change between at admission and discharge, (Estimate: 0.022, standard error: 0.012, P < .0001). Patient gender, age, surgical site, performance status, the American Society of Anesthesiologists (ASA) physical status classification, operation time, amount of blood loss, and serum albumin level at admission were also significant predictors. Adjusted multivariate analysis of the effects of POMs on perioperative change of serum albumin level in all subjects reveled the significance of POMs intervention (estimate: 0.022, standard error: 0.012, P < .0001). These results suggest that POMs exerts significant positive effects on perioperative serum albumin levels in patients underwent surgery under general anesthesia.

Change in allodynia of patients with post-lingual nerve repair iatrogenic lingual nerve disorder.

PURPOSE: Mandibular third molar extractions are common treatment in oral maxillofacial surgery, but risk disturbance of the lingual nerves causing anesthesia, eating difficulty and allodynia, which can seriously reduce patient quality of life. This study investigates the change in allodynia before and after repair in patients with lingual nerve disorder. SUBJECTS AND METHODS: This retrospective cohort study comprises the 52 patients with affected lingual nerve after third molar extraction at our hospital over a 7-year period. Pre- and postoperative (6 months and 12 months) neurosensory records were analyzed. RESULTS: Fifty-two patients underwent lingual nerve repair and returned for at least 1 year of follow-up. Mean age was 36.8 ± 11.9. Median interval between injury and surgery was 5 (4, 8) months. In 92.9% of those with pain before surgery, allodynia disappeared postoperatively. CONCLUSIONS: This study shows that microsurgical lingual reconstructions are effective in patients with preoperative allodynia, but a small number of patients may have remaining allodynia after surgery. Large-scale, more detailed analysis of such cases is required.

A multicenter retrospective investigation on the efficacy of perioperative oral management in cancer patients.

Patients develop a number of oral complications during cancer treatments. Oral bacteria are associated with the onset of dental focal infections and the progression of oral mucositis. Dental focal infections are frequently associated with the systemic onset of bacteremia, sepsis, and pneumonia. The degeneration of oral function with these complications may become an obstacle to cancer treatments. Although comprehensive oral management, including oral care, the removal of dental focal infections, and improvements in oral function with dentures, is conducted for cancer patients in Japan, few studies have assessed its efficacy.The aim of the present study was to investigate the incidence of dental/oral complications in cancer patients with perioperative oral managements (POMs) based on a large number of case series with a multicenter retrospective analysis.The medical records of cancer patients with POMs were retrospectively reviewed and the incidence of oral complications and efficacy of oral management were investigated.A total of 2744 cancer patients with POMs (1684 males and 1080 females, mean age 65.9 ±â€Š13.0 years) were included and investigated in the present study. Among these patients, 2097 (76.4%) started POM before the initiation of cancer treatments, with 2130 (77.6%) receiving oral care only and 391 (14.2%) being subjected to invasive treatments, such as tooth extraction. The incidence of dental focal infections during the period of cancer treatments was 8.2%. The most frequent infection was acute periodontitis, including alveolar abscesses (112 patients, 4.1%). The incidence of grade 2 and 3 oral mucositis was 2.8%. Prolonged fever was observed in 113 patients (4.1%), with 7 having dental focal infections (6.2%). These incidence rates were lower than those reported previously.Based on analyses of a large number of patients, the present results support the efficacy of oral management in cancer patients. However, further studies are needed to establish adequate oral management guidelines for cancer patients.

Risk of lingual nerve injuries in removal of mandibular third molars: a retrospective case-control study.

BACKGROUND: Through the analysis of clinical data, we attempted to investigate the etiology and determine the risk of severe iatrogenic lingual nerve injuries in the removal of the mandibular third molar. METHODS: A retrospective chart review was performed for patients who had undergone microsurgical repair of lingual nerve injuries. The following data were collected and analyzed: patient sex, age, nerve injury side, type of impaction (Winter's classification, Pell and Gregory's classification). Ratios for the respective lingual nerve injury group data were compared with the ratios of the respective data for the control group, which consisted of data collected from the literature. The data for the control group included previous patients that encountered various complications during the removal of the mandibular third molar. RESULTS: The lingual nerve injury group consisted of 24 males and 58 females. The rate of female patients with iatrogenic lingual nerve injuries was significantly higher than the control groups. Ages ranged from 15 to 67 years, with a mean age of 36.5 years old. Lingual nerve injury was significantly higher in the patient versus the control groups in age. The lingual nerve injury was on the right side in 46 and on the left side in 36 patients. There was no significant difference for the injury side. The distoangular and horizontal ratios were the highest in our lingual nerve injury group. The distoangular impaction rate in our lingual nerve injury group was significantly higher than the rate for the control groups. CONCLUSION: Distoangular impaction of the mandibular third molar in female patients in their 30s, 40s, and 50s may be a higher risk factor of severe lingual nerve injury in the removal of mandibular third molars.

Evaluation of the Treatment Strategies for Medication-Related Osteonecrosis of the Jaws (MRONJ) and the Factors Affecting Treatment Outcome: A Multicenter Retrospective Study with Propensity Score Matching Analysis.

Medication-related osteonecrosis of the jaw (MRONJ) is an adverse event that may inhibit the treatment of primary disease and remarkably influence the patient's quality of life. The treatment methods for MRONJ, nonsurgical and surgical, are controversial, with no agreement as to which method provides the best outcome and should therefore be recommended. This multicenter retrospective study aimed to investigate the treatment methods and outcome in a large number of patients with MRONJ in Japan, utilizing propensity score matching analysis. A total of 361 patients with MRONJ, at eight hospitals, were registered in this study retrospectively. Various demographic and treatment-related variables were examined and analyzed to determine their correlation with the treatment outcome. After propensity score matching for treatment methods (nonsurgical versus surgical treatment), 176 patients were analyzed by logistic regression. It was shown that those with low-dose administration of an antiresorptive agent and surgical treatment had better outcomes. Furthermore, in 159 patients who underwent surgical treatment, those who underwent extensive surgery experienced significantly better treatment outcomes than those who underwent conservative surgery. This is the first study to compare treatment methods for MRONJ using propensity score matching analysis. The results indicated that extensive surgical treatment should be performed as first-choice therapy for patients with MRONJ. © 2017 American Society for Bone and Mineral Research.

A Case of Verruciform Xanthoma Arising in the Tongue.

Verruciform Xanthoma (VX) is a rare lesion of the oral cavity. Histologically, it is characterized by papillary or verrucous proliferation of squamous epithelium and numerous foam cells. VX arising in the tongue is comparatively rare, as most cases of VX in oral cavity occur in gingiva. A 65-year-old woman was referred to our clinic with a mass on the left side of the tongue. The lesion was yellowish, and its surface was granulated. The patient had neither tenderness nor any symptoms. The lesion was clinically diagnosed to be a benign tumor, and hence, biopsy was performed, according to which it was diagnosed as hyperparakeratosis. Based on this diagnosis, the tumor was excised under general anesthesia. Histopathologically, the tumor consisted of stratified squamous epithelium with parakeratosis and elongated rete ridges. Aggregation of foam cells was observed between and under the rete ridges. From these features, a diagnosis of VX was made. The patient has had no local recurrence as of three years post-operatively.

Expression of caveolin-1 and its correlation with cisplatin sensitivity in oral squamous cell carcinoma.

PURPOSE: Cisplatin (CDDP) is widely used for chemotherapy of oral squamous cell carcinoma (OSCC). However, the mechanism of resistance to CDDP is unclear. Recently, caveolin-1 was identified as being associated with both metastasis and multidrug resistance. In the present study, we showed that caveolin-1 expression is significantly related to chemosensitivity in OSCC. METHODS: We established a CDDP-resistant cell line, H-1R, from the parental OSCC cell line, H-1. Caveolin-1 expression was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) in both cell lines. We analyzed expression of caveolin-1 in 30 OSCC biopsy specimens and investigated the relationship between expression of caveolin-1 and patients' clinicopathological parameters and chemotherapeutic responses. RESULTS: The 3-(3,4-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that H-1R has a ten-times greater resistance to CDDP than H-1 has. The level of caveolin-1 expression in H-1R was significantly decreased in comparison with that in H-1 by real-time RT-PCR analysis. Positive caveolin-1 immunostaining correlated positively with a complete response (16/20, 80.0%). However, negative immunostaining was found in 6/7 (85.7%) cases with no response. Positive immunohistochemical staining of caveolin-1 correlated positively with chemosensitivity to CDDP-based combination chemotherapy (P=0.02). CONCLUSIONS: These results suggest that overexpression of the caveolin-1 gene may provide novel diagnostic markers associated with CDDP sensitivity in OSCC.

Establishment and gene analysis of a cisplatin-resistant cell line, Sa-3R, derived from oral squamous cell carcinoma.

Cisplatin (CDDP) is widely used for chemotherapy of many malignancies, especially of oral squamous cell carcinoma (SCC). However, because the mechanism of resistance to CDDP is unclear, we established a CDDP-resistant cell line, Sa-3R, from a CDDP-sensitive cell line, Sa-3, which was derived from moderately differentiated SCC of the lower gingiva. The 3-(3,4-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide assay indicated that Sa-3R has 7.5-fold greater resistance to CDDP than Sa-3. Comparing gene expression levels in the cell lines using an in-house cDNA microarray, which represented 2,201 oral disease origin genes, many differentially expressed genes were identified. The ATP-binding cassette transporter genes (MDR-1, MRP-1, and MRP-2), and FANCONI, GRP58, FLJ12089, and SPINT-2 were up-regulated, whereas FOSL1, MRPS27, and PGK-1 were down-regulated. These results were confirmed by semiquantitative reverse transcriptase-polymerase chain reaction. The Sa-3/Sa-3R cell lines could be useful to identify the candidates responsible for the mechanism of CDDP-resistance and the up- or down-regulated genes identified by the gene expression profiles in the Sa-3R cell line may be, in part, associated with the mechanism.

Establishment and characterization of a cisplatin-resistant oral squamous cell carcinoma cell line, H-1R.

Cisplatin (CDDP) is a widely used potent chemotherapeutic agent for many malignancies. However, the mechanism of resistance to CDDP remains unclear. To investigate the molecular mechanism, we established a CDDP-resistant cell line (H-1R) from a CDDP-sensitive cell line (H-1) which was derived from moderately differentiated squamous cell carcinoma of the lower gingiva. The 3-(3,4-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay indicated that H-1R had a 10-fold greater resistance to CDDP than H-1. When we compared gene expression levels in the cell lines using an in-house cDNA microarray, which represented 2,201 genes originating from normal oral tissue, primary oral cancer, and oral cancer cell lines, 12 genes showing elevated mRNA expression in H-1R compared with H-1 were identified. Among them, the up-regulated expression of ATP-binding cassette transporter genes (MDR1, MRP1, and MRP2), CD55, and PGK1 and down-regulated expression of Caveolin 1 were further confirmed by semiquantitative reverse transcriptase-polymerase chain reaction (PCR) or real-time PCR. Our results suggest that H-1 and H-1R cell lines could be useful for elucidating the candidate genes responsible for CDDP resistance, including the genes found in this study.

Analysis of the mandibular movement by simultaneous multisection continuous ultrafast MRI.

PURPOSE: Using simultaneous multiple cross-sectional imaging, we imaged four cross sections, including the mandibular midline and the right and left temporomandibular joints, to observe one movement of mouth opening and closing and analyze the movement of the mandible and temporomandibular joints. MATERIALS AND METHODS: Four cross sections, including the midsagittal section of the mandible, the sagittal sections of the right and left temporomandibular joints and the horizontal section containing the heads of right and left temporomandibular joints, were imaged simultaneously. The imaging was conducted in 10 male and female volunteers. RESULTS: In all volunteers, the relationship of the mandibular movement on the median line with the right and left temporomandibular joints was observed. Images of the volunteers with trismus indicated the condition in which the right and left temporomandibular joints did not move in keeping with each other but moved independently from each other. CONCLUSION: Complex movement of the temporomandibular joint was first evaluated by simultaneous multiple cross-sectional MRI for the movement of mandible and temporomandibular joints.

Expression of ADAMTS-5 in deformed human temporomandibular joint discs.

OBJECTIVE: To study the expression of a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5) in tissue samples of deformed human temporomandibular joint (TMJ) discs and cells obtained from the discs. MATERIALS AND METHODS: Eleven adult human TMJ discs (nine diseased discs and two normal discs) were used in this study. The nine diseased discs were obtained from nine patients with internal derangement (ID) and osteoarthritis (OA) in the TMJ. These patients all had anteriorly displaced discs and deformed mandibular condyles, making conservative therapy impossible. The tissues were immunohistochemically stained using ADAMTS-5 antibodies. In addition, an articular disc cell line from one case was established by collagenase treatment. The subcultured cells under both normal and hypoxic conditions (O2: 2%) were incubated for 3, 6, 12 and 24 h after addition of interleukin-1beta (IL-1beta) (1 ng/mL). Subsequently, the expression of ADAMTS-5 was examined using reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The control group showed negative reactions on immunohistochemical staining. The discs extracted from cases with ID and OA presented positive reactions for ADAMTS-5. The expression of ADAMTS-5 mRNA increased under both normoxia and hypoxia with the addition of IL-1beta, and the peak was observed after 3 h. CONCLUSION: These results suggest that ADAMTS-5 is related to deformation and destruction of human TMJ discs affected by ID and OA.

Epidemiological study of malignant tumors in the oral and maxillofacial region: survey of member institutions of the Japanese Society of Oral and Maxillofacial Surgeons, 2002.

We studied 1809 patients with oral cancer who visited and were treated, in 2002, at the 148 institutions certified as training facilities by the Japanese Society of Oral and Maxillofacial Surgeons. Of these institutions, 39 are dental university hospitals, 44 are medical university hospitals, 64 are general hospitals, and for 1 institution, the classification was not known. The patients consisted of 1071 (59.2%) males and 738 (40.8%) females (male: female ratio, 1.45:1), who had a average age of 65.2 years. The tongue (40.2%) was the most common site affected, followed by the gingiva (32.7%), buccal mucosa (10.1%), and oral floor (9.0%). There were 6 cases of multiple intraoral cancers. On histopathological examinations, squamous cell carcinoma (88.7%) was the most common type found, followed by adenoid cystic carcinoma (2.1%), and mucoepidermoid carcinoma (1.7%). Cases classified as T2N0 were the most common (32.1%), followed by T1N0 (21.4%), T4N0 (8.0%), and T2N1 (7.6%). Distant metastasis occurred in 17 patients (1.0%). Nonepithelial tumors, among which malignant melanoma was the most common type, accounted for 1.8% of the tumors. The sizes of the nonepithelial malignant tumors ranged from 1.0 to 7.0 cm, with an average size of 3.7 cm.