Development of a tool for monitoring the jaw-opening pace and preliminary comparison the pace between young and old ages.

OBJECTIVES: Studies have demonstrated that high-speed jaw-opening exercises are effective in improving swallowing function. However, there has been no objective tool available for monitoring jaw-opening pace. This study aimed to develop an objective tool for monitoring and validating jaw-opening pace and compare it between young and old ages from different age groups. MATERIALS AND METHODS: A load cell plug-in jaw pad connected to an automatic recording and analysis system was used to record jaw-opening motions for offline analysis. We recruited 58 healthy volunteers from different age groups (20-39 y/o; 40-59y/o; 60-79y/o). During a 2-min recording session, each participant was instructed to fully open and close their jaw as quickly as possible while wearing a sensor. Bland-Altman plot, paired t-test and Pearson's correlation test were used to compare the number of jaw-opening motions between manual counting and automatic software analysis. The number of jaw-opening motions during the 2-min recording was compared between the three age groups. RESULTS: Automated analysis of jaw-opening pace was efficient and equally comparable with the traditional manual counting method across the three age groups. A declining trend in jaw-opening pace among the old age group was found but with no statistically significant difference. CONCLUSIONS: A jaw-opening motion monitoring tool with reliable automatic pace analysis software was validated in young and old ages. The jaw-opening pace demonstrated a tendency to decline with age. CLINICAL RELEVANCE: This monitoring tool can also be used to provide visual feedback during jaw-opening motion training in pace control.

Diagnostic value of nerve conduction study in NOTCH2NLC-related neuronal intranuclear inclusion disease.

BACKGROUND AND AIMS: Neuronal intranuclear inclusion disease (NIID) is a rare progressive neurodegenerative disorder mainly caused by abnormally expanded GGC repeats within the NOTCH2NLC gene. Most patients with NIID show polyneuropathy. Here, we aim to investigate diagnostic electrophysiological markers of NIID. METHODS: In this retrospective dual-center study, we reviewed 96 patients with NOTCH2NLC-related NIID, 94 patients with genetically confirmed Charcot-Marie-Tooth (CMT) disease, and 62 control participants without history of peripheral neuropathy, who underwent nerve conduction studies between 2018 and 2022. RESULTS: Peripheral nerve symptoms were presented by 53.1% of patients with NIID, whereas 97.9% of them showed peripheral neuropathy according to electrophysiological examinations. Patients with NIID were characterized by slight demyelinating sensorimotor polyneuropathy; some patients also showed mild axonal lesions. Motor nerve conduction velocity (MCV) of the median nerve usually exceeded 35 m/s, and were found to be negatively correlated with the GGC repeat sizes. Regarding the electrophysiological differences between muscle weakness type (n = 27) and non-muscle weakness type (n = 69) of NIID, nerve conduction abnormalities were more severe in the muscle weakness type involving both demyelination and axonal impairment. Notably, specific DWI subcortical lace sign was presented in only 33.3% of muscle weakness type, thus it was difficult to differentiate them from CMT. Combining age of onset, distal motor latency, and compound muscle action potential of the median nerve showed the optimal diagnostic performance to distinguish NIID from major CMT (AUC = 0.989, sensitivity = 92.6%, specificity = 97.4%). INTERPRETATION: Peripheral polyneuropathy is common in NIID. Our study suggest that nerve conduction study is useful to discriminate NIID.

Factors related to microimplant-assisted rapid palatal expansion in teenagers and young adults: A cone-beam computed tomography study.

INTRODUCTION: For patients with maxillary transverse deficiency, selecting an appropriate therapeutic method is important for the treatment effect and prognosis. Our study aimed to explore factors related to microimplant-assisted rapid palatal expansion (MARPE) in teenagers and young adults using cone-beam computed tomography. METHODS: Twenty-five patients who underwent MARPE were included in this retrospective study from February 2014 to June 2019. Midpalatal suture density (MPSD) ratio, midpalatal suture maturation (MPSM), bone effect, dentoalveolar effect, and dental effect in maxillary first molar were evaluated using cone-beam computed tomography. Spearman correlation analysis was used to analyze the correlation between the MPSD ratio, MPSM, age, and the expansion amount generated by MARPE. RESULTS: Twenty-five patients (mean age, 19.84 ± 3.96 years; range, 15-29 years) with maxillary transverse deficiency were analyzed. Age was negatively correlated with bone expansion, alveolar expansion, and alveolar change (all P <0.05). There was a negative correlation between MPSM and nasal cavity variation, bone expansion, and alveolar change (all P <0.05). The bone expansion was negatively correlated with MPSD ratio 3 (r = -0.417; P <0.05) and MPSD ratio 4 (all P <0.05). CONCLUSIONS: Age, MPSM, and MPSD ratio were significantly related to the MARPE effect. Age, MPSM, and MPSD ratio should be considered when choosing MARPE.

Treatment effects after maxillary expansion using invisalign first system vs. acrylic splint expander in mixed dentition: a prospective cohort study.

BACKGROUND: Invisalign First System (First) is a new type of orthodontic appliance for maxillary arch expansion in mixed dentition children. Till now, few studies have evaluated the expansion effects of First versus other appliances. What's more, most studies of arch expansion did not include a natural group to rule out growth effects. This prospective cohort study aimed to evaluate the dental and dentoalveolar effects using First or acrylic splint rapid maxillary expander (RME) in adolescents excluding growth factors. MATERIALS AND METHODS: After screening by strict inclusion criteria and propensity score matching (PSM), fifty-one patients were included: First group (n = 17), RME group (n = 17), and natural growth (NG) group (n = 17). Nine indicators including dental arch width, dentoalveolar arch width, and inclination of the molars were measured on digital dental casts at baseline (T0) and six-month follow-up (T1). Paired t-tests were used for intra-group results, and two-sample independent t-tests were used for inter-group comparisons. RESULTS: There was no significant increase in all indicators within six months in the NG group (p > 0.05). In the First group and RME group, all width indicators were significantly increased after treatment (p < 0.05). The RME group exhibited greater expansion than the First group in intercanine width, first interpremolar width, second interdeciduous molar width, first intermolar width, arch perimeter, intercanine dentoalveolar width, intermolar dentoalveolar width, and inclination of the molars (p < 0.05). Whereas, there was no significant difference in arch depth between the two treated groups. CONCLUSIONS: Both First and RME can expand the maxillary arch in mixed dentition. In case of mild to moderate maxillary transverse deficiency (MTD), Invisalign First System could be a reasonable option. RME shows significant better efficiency of dental arch expansion than First, recommended for patients with severe MTD. TRIAL REGISTRATION: This prospective study was registered on ClinicalTrials.gov (01/02/2022, registration number: ChiCTR2200056220). The trial was approved by the Ethical Committee of the Hunan Xiangya Stomatological Hospital Central South University (20,200,088), and informed consent was obtained from all subjects and their legal guardian(s).

Morphological changes in alveolar bone thickness and height after orthodontic proclination or labial movement combined with autogenous soft tissue grafting: a CBCT evaluation.

BACKGROUND: Autogenous soft tissue grafting is indicated in thin gingival biotypes before orthodontic proclination or labial movements to increase the keratinized gingiva and prevent gingival recession. However, its effect on local alveolar bone remodeling is unclear. The aim of this study was to investigate the effects of autogenous soft tissue grafting on local alveolar bone after orthodontic proclination or labial movements. METHODS: Sixteen patients with a thin scalloped gingival biotype, narrow keratinized gingiva, or thin cortical bone requiring orthodontic proclination or labial movement of teeth were included. Cone-beam computed tomography (CBCT) images were obtained before grafting and at least 6 months after surgery. Sixty mandibular teeth were included, and the vertical bone level and horizontal labial bone thickness were measured. The results were compared using paired t-tests or Wilcoxon signed-rank test. RESULTS: The horizontal labial bone thickness increased, especially at 6 mm below the cementoenamel junction (CEJ) in the mandibular central and lateral incisors (P < 0.05). The total alveolar bone area of the canines, first premolars, and second premolars increased at 3, 6, and 9 mm below the CEJ, respectively, and the differences were statistically significant (P < 0.05). Additionally, vertical bone height increased minimally on the labial side, but the differences were not statistically significant (P > 0.05). CONCLUSIONS: New bone regeneration was observed on the labial (pressure) side after autogenous soft tissue grafting, which may represent a mechanism to effectively prevent gingival recession and maintain periodontal health. IRB APPROVAL: All the experimental procedures involving humans in this study were approved by the Medical Ethics Committee of Xiangya Stomatological Hospital, Central South University ( No. 20190048).

The association between the severity of periodontitis and osteonecrosis of the jaw in patients with different cancer locations: a nationwide population-based study.

OBJECTIVES: To determine the relation between the severity of periodontitis and osteonecrosis of the jaw (ONJ) occurrence among different cancer locations and estimate the effect of dental care on ONJ prevention in cancer patients. MATERIALS AND METHODS: This population-based cross-sectional study was conducted through the Longitudinal Health Insurance Database, Taiwan. Patients with malignancies were collected and subdivided into groups according to their different cancer locations, the severity of periodontitis, and dental care. Multivariable logistic regression analysis was performed to assess the associations between ONJ and ONJ-related factors. RESULTS: A total of 8,234 ONJ patients and 32,912 control patients were investigated. Lip, oral cavity, and pharynx malignancies had the highest ONJ risk among all cancer locations (OR from 3.07 to 9.56, P < 0.01). There is a linear relationship between different severities of periodontitis and ONJ. Patients with radiotherapy and severe periodontitis had the highest ONJ risk (adjusted OR, 9.56; 95% CI, 5.34-17.1). Patients with good dental care had a lower ONJ risk. CONCLUSIONS: The periodontal condition and cancer location showed a significant impact on the risk of developing ONJ after adjusting for bisphosphonate use. Good dental care could decrease the risk of ONJ in cancer patients. The severity of periodontitis might be a target to predict the potency of ONJ. CLINICAL RELEVANCE: Dentists must be vigilant about the increased risk of ONJ in cancer patients with periodontitis, especially in the head and neck cancer population. Good dental care is advised for cancer patients with severe periodontitis.

The correlation between two occlusal analyzers for the measurement of bite force.

BACKGROUND: Occlusal force represents masticatory function. Using quantifiable occlusal indicators provides a more objective occlusal force evaluation. In the recent dental practice, digital methods such as the Dental Prescale II (DP2, GC Corp., Tokyo, Japan) and T-scan (T-Scan III v8; Tekscan Inc.) are commonly used in clinics to evaluate treatment outcomes. The T-scan provides the relative bite force (%) compared to the maximal bite force on individual teeth or the unilateral arch. The DP2 can quantify occlusal force, measured in newtons (N), on the half arch or the overall bite, but it is difficult to identify the bite force on an individual tooth. It is difficult to select a device that fulfils all the requirements to record occlusal force. This study aimed to investigate the association between the bite measured by the DPS2 and T-scan to determine whether the measured bite force is comparable through calculation. METHODS: A total of 80 healthy adults, including 41 women and 39 men with a mean age of 38.2, were requested to bite pressure sensitive film sheets ten minutes apart. Linear regression analysis was used to estimate the measured bite force by the DP2 and T-scan. RESULTS: There was a significant positive correlation between the occlusal force measured by the DP2 and T-scan (P < 0.01) when intercept was equal to zero as confounders were adjused. These results provided the comparability of the measured occlusal forces determined by the DP2 and T-scan. CONCLUSION: The estimated bite force determined by DP2 and T-Scan is convertible using the linear equation from this study to increase the value for clinical applications. The estimated bite force from the two quantifiable occlusal indicators are comparable. The two commercially available quantifiable occlusal indicators can be fully adapted to all clinical requirements according to this result.

The impact of timing and modalities of dental prophylaxis on the risk of 5-fluorouracil-related oral mucositis in patients with head and neck cancer: a nationwide population-based cohort study.

PURPOSE: This study investigated the impact of dental prophylaxis on 5-fluorouracil (5-FU)-related oral mucositis (OM) according to the head and neck cancer (HNC) locations and treatment times. METHODS: A total of 13,969 HNC participants, including 482 5-FU-related OM subjects and 13,487 comparisons were enrolled from the Longitudinal Health Insurance Database for Catastrophic Illness Patients of Taiwan between 2000 and 2008. All subjects were stratified into subgroups based on the times to perform chlorhexidine use, scaling, and fluoride application before 5-FU administration. The dental prophylaxis related to 5-FU-related OM was estimated by multiple logistic regression and represented with odds ratio (OR) and 95% confidence interval (CI). RESULTS: Fluoride gel application and scaling significantly impacted on OM development (p < 0.001), and the joint effect of fluoride gel and scaling induced 5-FU-related OM (OR = 3.46, 95% CI = 2.39-5.01). The risk of OM was raised 2.25-fold as scaling within 3 weeks before 5-FU-related chemotherapy (95% CI = 1.81-2.81), and a 3.22-fold increased risk of OM while fluoride gel was applied during 5-FU-related treatment (95% CI = 1.46-7.13). CONCLUSION: Dental prophylaxis significantly affected 5-FU-related OM in the HNC population. A short interval between dental scaling or fluoride application and 5-FU administration may be associated with higher prevalence of OM. Scaling simultaneously combined with chlorohexidine promoted 5-FU-related OM in specific HNC patients excluding the oral cancer and nasopharyngeal cancer population. Proper timing of the prophylactic dental treatments prior to 5-FU therapy could reduce the risk to develop 5-FU-related OM.

Comparing image qualities of dental cone-beam computed tomography with different scanning parameters for detecting root canals.

BACKGROUND/PURPOSE: Cone-beam computed tomography (CBCT) is a useful device in creating 3-dimensional images in the examining area of dentistry and is one of the most common clinical methods in detecting second mesiobuccal (MB2) canals in maxillary molars. The aim of this in vitro study was to compare the image quality of the small field of view (FOV) CBCT with different rotation arcs and scanning speeds in the use of detecting root canals. METHODS: A dentate human skull was scanned in Morita 3D Accuitomo 170 with 4 × 4 cm FOV under 5 mA and 90 kVp. Two different rotation arcs (360° and 180°) and three different scanning modes (slow-speed mode, standard mode and high-speed mode) combined into six different groups. Five different levels of axial sections were selected from each group. Five endodontic specialists rated the image quality by focusing on the sharpness of the MB2 canal of the upper right first molar and the surrounding structures. RESULTS: Despite the rotation arcs, all the observers gave excellent ratings to images taken with slow-speed mode. The high-speed mode taken with 360° and 180° got the second lowest and the lowest ratings, respectively. Under the same scanning speed, the rotation arc did not have a significant difference in image quality. CONCLUSION: Slow-speed mode is inevitable in maintaining adequate image quality during taking CBCT. However, endodontists can use the half rotation mode to significantly reduce radiation dose, exposure time, and still maintain sufficient image quality for root canal anatomy assessment.

Displacement and stress distribution of the craniomaxillofacial complex under different surgical conditions: a three-dimensional finite element analysis of fracture mechanics.

OBJECTIVE: To provide a simplified treatment strategy for patients with maxillary transverse deficiency. We investigated and compared the fracture mechanics and stress distribution of a midline palatal suture under dynamic loads during surgically-assisted rapid palatal expansion. METHODS: Based on the cone-beam computed tomography (CBCT) data of a 21-year-old female volunteer, a three-dimensional model of the cranio-maxillofacial complex (including the palatal suture) was constructed. A finite element analysis model was constructed based on meshwork. After the yield strength of the palatal suture was set, an increasing expansion force (0-500 N) was applied within 140 ms to calculate the time-load curve, which mimicked nonsurgical bone expansion (model A). The same method was used to evaluate the fracture process, time and stress distribution of the palatal suture in maxillary lateral osteotomy-assisted (model B) and LeFort osteomy I (LFIO)-assisted expansion of the maxillary arch (model C). RESULTS: Compared with model A, the palatal suture of model B and model C showed a faster stress accumulation rate and shorter fracture time, and the fracture time of model B and model C was almost identical. Compared with model A, we discovered that model B and model C showed greater lateral extension of the maxilla, and the difference was reflected mainly in the lower part of the maxilla, and there was no difference between model B and model C in lateral extension of the maxilla. CONCLUSIONS: Compared with arch expansion using nonsurgical assistance (model A), arch expansion using maxillary lateral wall-osteotomy (model B) or LFIO had a faster rate of stress accumulation, shorter time of fracture of the palatal suture and increased lateral displacement of the maxilla. Compared with arch expansion using LFIO (model C), arch expansion using lateral osteotomy (model B) had a similar duration of palatal suture rupture and lateral maxillary extension. In view of the trauma and serious complications associated with LFIO, maxillary lateral wall-osteotomy could be considered a substitute for LFIO.

The association between dental therapy timelines and osteoradionecrosis: a nationwide population-based cohort study.

OBJECTIVES: The study aimed to investigate the timeline association with specific dental therapy and osteoradionecrosis (ORN) in oral cancer patients. MATERIALS AND METHODS: A total of 7394 oral cancer patients, including 198 ORN subjects, were retrieved from a Longitudinal Health Insurance Database for Catastrophic Illness Patients of Taiwan and were analyzed with the Cox proportional hazard regression to compare the ORN risk of individual dental treatments under different dental treatments. RESULTS: The initial dental treatment time significantly impacted on the risk of ORN in oral cancer patients (P<0.05). Pre-radiotherapy endodontic treatment and post-radiotherapy scaling or subgingival curettage increased ORN prevalence (hazard ratio [HR], 2.28 and 1.77, respectively). Endodontic treatment within 2 weeks to 1 month prior to radiotherapy increased the ORN risk by 5.83-fold. Dental scaling or subgingival curettage initialized from three to 6 months post-radiotherapy raised the ORN prevalence by 2.2-fold. Exodontia initialized within 2 weeks before radiotherapy (HR=1.49) or 1 to 3 months after radiotherapy (HR=2.63) greatly increased ORN prevalence. To perform oral surgery from 3 months pre-radiotherapy to 6 months after radiotherapy increased the 1.85-fold ORN risk. The chemotherapy combined oral surgery increased the ORN prevalence by 2.55-fold. CONCLUSIONS: Timing of dental treatment, including pre-radiotherapy endodontic treatment, post-radiotherapy scaling or subgingival curettage, and oral surgery or exodontia before and after radiotherapy, could closely relate to ORN development in oral cancer patients. CLINICAL RELEVANCE: Choosing right time to perform appropriate dental treatment could effectively reduce oral infection and ORN risk.

Prosthetic design related to peri-implant bone resorption in microvascular free fibular flap among patients with oral cancer: A retrospective clinical study.

STATEMENT OF PROBLEM: Prosthetic rehabilitation is challenging after tumor excision in patients with oral cancer. Prosthetic parameters may be compromised because of the physical limitations of the oral cavity. Although microvascular free fibular flaps are a common treatment modality for mandibular reconstruction and allow the placement of dental implants, fibular resorption under long-term functional loading is still a controversial issue. Research focusing on how prosthetic design affects fibular resorption around dental implants in an oral cancer population is lacking. PURPOSE: The purpose of this retrospective clinical study was to correlate the success of implant-supported prostheses in microvascular free fibular flaps with occlusal force and fibular resorption around the implants 7 years after functional loading. MATERIAL AND METHODS: The T-Scan III was used to measure occlusal force in 13 participants with oral cancer. Forty-seven successful endosseous dental implants (Biomet 3i) under functional loading in the participants from 2010 to 2017 were analyzed retrospectively. Prosthetic design including fibular length, rehabilitated arch length, and crown-to-implant ratios was estimated from panoramic radiographs. The intergonial distance was used to calibrate the panoramic radiographs to enhance accuracy. To compensate for panoramic distortion, all parameters were represented as a ratio such as fibular length/mandibular width; implant-supported prosthesis length/mandibular dental arch length; implant-supported prosthesis length/maxillary dental arch length; and mandibular dental arch length/maxillary dental arch length. A generalized estimating equation was used for longitudinal analysis to estimate the impact of variables on fibular resorption around the implants. RESULTS: Increased length of the implant-supported prostheses compared with maxillary and mandibular dental arch length significantly impaired the maximal occlusal force (P=.045 and P=.029). The crown-to-implant ratios in the fibular flaps were not correlated with fibular resorption around the implants under long-term functional occlusion (P>.05). The increased ratio of the implant-rehabilitated mandibular to maxillary dental arch length showed a statistically significant tendency to reduce fibular resorption around the implants (P=.007). CONCLUSIONS: Crown-to-implant ratios were not significantly correlated with maximal occlusal force or fibular resorption around dental implants. Increasing the length of the reconstructed mandibular implant-supported prosthesis in the fibular flap will reduce occlusal force. The rehabilitated mandibular dental length should be as long as the maxillary arch for optimum occlusal stress distribution to maintain the peri-implant fibula bone level.

Changes of the upper airway and bone in microimplant-assisted rapid palatal expansion: A cone-beam computed tomography (CBCT) study.

OBJECTIVE: To evaluate the changes of maxillary expansion and upper airway structure after microimplant assisted rapid palatal expansion (MARPE) using cone-beam computed tomography (CBCT). METHODS: This retrospective study included 19 subjects (15 females and 4 males) aged 15-29 years old (mean, 19.95±4.39 years) with maxillary transverse deficiency treated with MARPE. CBCT was performed at the initial diagnosis and 3 months after MARPE treatment. Measurements were taken to evaluate the amount of total expansion, skeletal expansion, and dental expansion at the maxillary first premolar (P1), second premolar (P2), first molar (M1), second molar (M2) regions and upper airway changes. RESULTS: After MARPE treatment, the maxillary skeletal base expansion, skeletal expansion, alveolar expansion and dental expansion were achieved at the P1, P2, M1, M2 region. The nasopharyngeal volume significantly increased 8.48% after MARPE treatment compared with that before the treatment (P < 0.05). The change of nasal lateral width (NLW) was also significantly different before and after MARPE (P < 0.05). However, there were no statistically significant change in the oropharyngeal, palatopharyngeal, glossopharyngeal and airway total volume (all P > 0.05). CONCLUSIONS: MARPE can produce more transverse bone expansion, relieve maxillary transverse deficiency and improve upper airway ventilation.

Increased salivary microvesicles are associated with the prognosis of patients with oral squamous cell carcinoma.

Microvesicles (MVs), which are cell-derived membrane vesicles present in body fluids, are closely associated with the development of malignant tumours. Saliva, one of the most versatile body fluids, is an important source of MVs. However, the association between salivary MVs (SMVs) and oral squamous cell carcinoma (OSCC), which is directly immersed in the salivary milieu, remains unclear. SMVs from 65 patients with OSCC, 21 patients with oral ulcer (OU), and 42 healthy donors were purified, quantified and analysed for their correlations with the clinicopathologic features and prognosis of OSCC patients. The results showed that the level of SMVs was significantly elevated in patients with OSCC compared to healthy donors and OU patients. Meanwhile, the level of SMVs showed close correlations with the lymph node status, and the clinical stage of OSCC patients. Additionally, the ratio of apoptotic to non-apoptotic SMVs was significantly decreased in OSCC patients with higher pathological grade. Consistently, poorer overall survival was observed in patients with lower ratio of apoptotic to non-apoptotic SMVs. In conclusion, the elevated level of SMVs is associated with clinicopathologic features and decreased survival in patients with OSCC, suggesting that SMVs are a potential biomarker and/or regulator of the malignant progression of OSCC.

The association with xerostomia from sialadenitis and the jaw osteonecrosis in head and neck cancer population: a nationwide cohort study.

OBJECTIVES: Determine the association between sialadenitis and osteonecrosis of the jaw (ONJ) in head and neck cancer (HNC) patients with varying severity of sialadenitis, treatment modalities, and cancer locations. MATERIALS AND METHODS: A total of 40,168 HNC patients, including 1907 ONJ subjects and 7559 matched comparisons, were enrolled from a Longitudinal Health Insurance Database for Catastrophic Illness Patients of Taiwan between 2000 and 2006. The association with sialadenitis and ONJ was estimated by logic regression and presented as the odds ratio (OR) and 95% confidence intervals (CIs). RESULTS: The occurrence of sialadenitis increased the risk of ONJ by 2.55-fold in HNC patients (95% CI = 2.20-2.95). The ONJ incidence was proportion to sialadenitis severity (OR = 2.53 to 4.43). Irradiated HNC patients had a higher tendency to develop jaw necrosis (osteoradionecrosis, ORN) (OR = 5.05, 95% CI = 4.39-5.80). When combined with irradiation exposure, sialadenitis significantly induced the occurrence of ORN (OR = 8.94, 95% CI = 7.40-10.8), especially in oral cancer patients (OR = 15.9 95% CI = 12.5-20.3). The risk of ONJ increased with radiotherapy dosage and duration, except for nasopharyngeal cancer (NPC) patients. CONCLUSIONS: There was a close association between sialadenitis and ONJ in the HNC population. The severity of sialadenitis was positive correlated to ONJ risk. Radiotherapy combined with sialadenitis significantly raised ORN incidence in HNC patients except for NPC patients. CLINICAL RELEVANCE: HNC patients complained that xerostomia from sialadenitis might increase the risk to develop ONJ, especially among those who received radiotherapy.

Effect of different zinc concentrations on partially-stabilized cement for vital pulp therapy.

BACKGROUND/PURPOSE: We have developed and investigated the partially-stabilized cements (PSC) with Zn for vital pulp therapy due to their short setting time and high cell biocompatibility. However, the effect of PSC with different concentrations of Zn on setting time and biocompatibility remained unknown. Therefore, the purpose of this study was to determine the optimal concentration of Zn to be synthesized with PSC for vital pulp therapy. METHODS: PSC with different weight percentages of Zn (5%, 7%, 10%) were synthesized to attain 5%Zn-PSC, 7%Zn-PSC, and 10%Zn-PSC. The initial and final setting times were measured using the Gillmore needles method, and the compressive strength tests were conducted using a universal testing machine. The phases of Zn-PSC powders were observed using an X-ray diffractometer (XRD). Human dental pulp stem cells (hDPSCs) were used to evaluate the biocompatibility and cytotoxicity of the materials via Alamar blue and LDH assays. Mineral trioxide aggregate (MTA) was used to be compared with Zn-PSC samples. RESULTS: The initial and final setting times of PSC with different concentrations of Zn were reduced considerably compared to those of MTA. The results also indicated that the initial and final setting times decreased as the weight % of Zn increased. 5%Zn-PSC had the highest compressive strength among all tested materials. 5%Zn-PSC samples also displayed comparatively higher cell biocompatibility than 7% and 10% Zn-PSC samples. However, there was no significant difference between the 5%Zn-PSC and MTA in cell biocompatibility. In addition, the results of the LDH release assay indicated a low level of cytotoxicity among all the test samples. CONCLUSION: 5%Zn-PSC has a shorter setting time, better mechanical properties, and good biocompatibility and thus it has great potential for vital pulp therapy.

Overexpression of Fra-1, c-Jun and c-Fos in odontogenic keratocysts: potential correlation with proliferative and anti-apoptotic activity.

AIMS: The purpose of this study was to explore the potential involvement of Fra-1, c-Jun and c-Fos, three vital members of the AP-1 complex, in the pathogenesis of odontogenic keratocysts (OKCs). METHODS AND RESULTS: Tissue samples, containing 10 normal oral mucosa (OM), 10 dentigerous cysts (DC) and 32 OKC specimens, were applied to investigate the expression levels of Fra-1, c-Jun and c-Fos by immunohistochemistry and real-time-quantitative polymerase chain reaction (RT-qPCR). The association between Fra-1, c-Jun and c-Fos expression levels and markers of proliferation [Ki-67, proliferating cell nuclear antigen (PCNA)], anti-apoptosis (Bcl-2) was then investigated in the OKC serial tissue sections. The results showed that Fra-1, c-Jun and c-Fos expression levels were increased significantly in OKCs compared to these in OM and DC tissue samples. Meanwhile, the expression levels of Fra-1, c-Jun and c-Fos were associated positively with the expression levels of Ki-67, PCNA and Bcl-2, as confirmed further by double-labelling immunofluorescence analysis and hierarchical analysis. CONCLUSIONS: This study revealed for the first time that Fra-1, c-Jun and c-Fos were overexpressed in OKCs and had a close correlation with proliferation and anti-apoptosis potential of OKCs.

Osteoradionecrosis of the Zygoma.

Osteoradionecrosis occurs in 4.74% to 37.5% of patients following radiation therapy for head and neck cancer. Osteoradionecrosis mostly happens in the mandible but seldom occurs in other maxillofacial bones. Here, the authors reported a rare case of zygomatic osteoradionecrosis which occurred after maxillectomy and then radiotherapy because of maxillary myoepithelial carcinoma. After resection of zygoma sequestrum, the defect was repaired with forehead flap and healed uneventfully.

Ultrasmall Magnetically Engineered Ag2Se Quantum Dots for Instant Efficient Labeling and Whole-Body High-Resolution Multimodal Real-Time Tracking of Cell-Derived Microvesicles.

Cell-derived microvesicles (MVs) are natural carriers that can transport biological molecules between cells, which are expected to be promising delivery vehicles for therapeutic purposes. Strategies to label MVs are very important for investigation and application of MVs. Herein, ultrasmall Mn-magnetofunctionalized Ag2Se quantum dots (Ag2Se@Mn QDs) integrated with excellent near-infrared (NIR) fluorescence and magnetic resonance (MR) imaging capabilities have been developed for instant efficient labeling of MVs for their in vivo high-resolution dual-mode tracking. The Ag2Se@Mn QDs were fabricated by controlling the reaction of Mn(2+) with the Ag2Se nanocrystals having been pretreated in 80 °C NaOH solution, with an ultrasmall size of ca. 1.8 nm, water dispersibility, high NIR fluorescence quantum yield of 13.2%, and high longitudinal relaxivity of 12.87 mM(-1) s(-1) (almost four times that of the commercial contrast agent Gd-DTPA). The ultrasmall size of the Ag2Se@Mn QDs enables them to be directly and efficiently loaded into MVs by electroporation, instantly and reliably conferring both NIR fluorescence and MR traceability on MVs. Our method for labeling MVs of different origins is universal and free of unfavorable influence on intrinsic behaviors of MVs. The complementary imaging capabilities of the Ag2Se@Mn QDs have made the long-term noninvasive whole-body high-resolution dual-mode tracking of MVs in vivo realized, by which the dynamic biodistribution of MVs has been revealed in a real-time and in situ quantitative manner. This work not only opens a new window for labeling with QDs, but also facilitates greatly the investigation and application of MVs.

Which Factors Influence the Shear Bond Strength of Sealant Materials?

PURPOSE: This study investigated the influence of several methodological details on the shear bond strength (SBS) testing of pit and fissure sealants. The following variables were considered: type of enamel surfaces, prismatic vs aprismatic enamel, etching time, and aging and shearing procedures. MATERIALS AND METHODS: The surfaces of 180 healthy human third molars were divided into 4 different sections (mesial, distal, buccal, and oral). After tooth separation, the specimens were randomly allocated to the following groups: 1) enamel preparation: prismatic vs aprismatic; 2) etching: 30 s vs 60 s; 3) aging: 1 day or 3 months vs 5000 thermocycles; 4) shearing: notched-edge method (ISO 29022:2013) vs knife-edge method. After following each protocol, SBS was determined using a universal testing machine, followed by failure mode analysis. Data were analysed using Mann-Whitney U-tests and regression analyses. RESULTS: In the aprismatic enamel group, the longer etching time resulted in slightly, not statistically significantly higher SBS. When aging sealants on aprismatic enamel with different procedures, significantly lower SBS was found for 5000 thermocycles. In the case of aprismatic enamel etched for 60 s and sheared with the notched-edge blade, there was no significant difference between the aging procedures. Failure mode analysis showed adhesive failures to be predominant. Simple linear regression revealed that all of the included factors significantly influenced SBS. In a multiple linear regression model, the variables "aprismatic enamel" and "distal surface" were associated with a higher SBS; "5000 thermocycles" reduced SBS significantly. CONCLUSION: Enamel grinding, aging method, and type of enamel surface significantly influenced the SBS.