The influence of different radiotherapy doses on the mechanical properties and microstructure of the enamel and dentin of human premolar teeth.

OBJECTIVE: Radiation therapy is applied in the treatment of head and neck cancer patients. However, oral-health-related side effects like hyposalivation and a higher prevalence of caries have been shown. This study aims to assess the influence of different radiotherapy doses on the mechanical properties, roughness, superficial microstructure, and crystallinity of the enamel and dentin of human premolar teeth. METHODS: Specimens (n = 25) were categorized into five groups based on the radiation dose received (0, 10, 30, 50, and 70 Gy). The enamel and dentin of these specimens were subjected to a microhardness tester, profilometer, atomic force microscopy (AFM), scanning electron microscopy (SEM), and X­ray diffraction (XRD) before and after different irradiation doses and compared to hydroxylapatite in each group. The data were analyzed using repeated-measures analysis of variance (ANOVA). RESULTS: Therapeutic radiation doses of 30, 50, and 70 Gy led to a decrease in the microhardness and an increase in the average roughness of the enamel, and rougher surfaces were observed in the mixed three-dimensional images. Moreover, in the dentin, a similar outcome could be observed for more than 10 Gy. The main crystalline phase structure remained hydroxylapatite, but the crystallinity decreased and the crystalline size increased above 10 Gy. The superficial micromorphology revealed granulation, fissures, and cracks in a dose-dependent manner. Radiation below 70 Gy had little effect on the hydroxylapatite concentration during the whole experiment. CONCLUSION: Above a radiation dose of 30 Gy, the micromorphology of the tooth enamel changed. This occurred for dentin above 10 Gy, which indicates that dentin is more sensitive to radiotherapy than enamel. The radiation dose had an effect on the micromorphology of the hard tissues of the teeth. These results illustrate the possible mechanism of radiation-related caries and have guiding significance for clinical radiotherapy.

Electronic symptom monitoring for home-based palliative care: A systematic review.

BACKGROUND: Coordination and communication challenges in home-based palliative care complicate transitions from hospital care. Electronic symptom monitoring enables real-time data collection, enhancing patient-provider communication. However, a systematic evaluation of its effectiveness in home-based palliative care is lacking. AIM: To analyze the feasibility, effectiveness, and limitations of electronic symptom monitoring in home-based palliative care, assess the evidence quality, identify the evidence gap, and suggest implications for future research and practice. DESIGN: This study uses systematic review, meta-analysis, and narrative synthesis (CRD42023457977) to analyze relevant studies until September 2023. DATA SOURCES: Electronic searches in MEDLINE, CENTRAL, and Embase until September 2023, complemented by hand-searching of references and citations. RESULTS: This study included twenty studies. The majority of patients positively engage in electronic symptom monitoring, which could improve their quality of life, physical and emotional well-being, and symptom scores without a significant increase in costs. However, firm conclusions about the effects of electronic symptom monitoring on outcomes like survival, hospital admissions, length of stay, emergency visits, and adverse events were limited due to significant variability in the reported data or inadequate statistical power. CONCLUSION: Introducing electronic symptom monitoring in home-based palliative care holds potential for enhancing patient-reported outcomes, potentially decreasing hospital visits and costs. However, inconsistency in current studies arising from diverse monitoring systems obstructs comparability. To advance, future high-quality research should employ standardized follow-up periods and established scales to better grasp the benefits of electronic symptom monitoring in home-based palliative care.

The damage and remineralization strategies of dental hard tissues following radiotherapy.

OBJECTIVES: This study pursued two main purposes. The first aim was to expound on the microscopic factors of radiation-related caries (RRC). Further, it aimed to compare the remineralization effect of different remineralizing agents on demineralized teeth after radiotherapy. METHODS: The enamel and dentin samples of bovine teeth were irradiated with different doses of radiation. After analysis of scanning electron microscope (SEM), X-Ray diffraction (XRD), and energy dispersive spectrometer (EDS), the samples irradiated with 50 Gy radiation were selected and divided into the demineralization group, the double distilled water (DDW) group, the Sodium fluoride (NaF) group, the Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) group, the NaF + CPP-ACP group, and the Titanium tetrafluoride (TiF4) group. After demineralization, remineralizing agents treatment, and remineralization, the samples were evaluated using SEM, atomic force microscope (AFM), EDS, and transverse microradiography (TMR). RESULTS: A radiation dose of 30 Gy was sufficient to cause damage to the dentinal tubules, but 70 Gy radiation had little effect on the microstructure of enamel. Additionally, the NaF + CPP-ACP group and the TiF4 group significantly promoted deposit formation, decreased surface roughness, and reduced mineral loss and lesion depth of demineralized enamel and dentin samples after radiation. CONCLUSIONS: Radiation causes more significant damage to dentin compared to enamel. NaF + CPP-ACP and TiF4 had a promising ability to promote remineralization of irradiated dental hard tissues. ADVANCES IN KNOWLEDGE: This in vitro study contributes to determining a safer radiation dose range for teeth and identifying the most effective remineralization approach for RRC.

Changes in the characteristics of dental emergencies under the influence of SARS-CoV-2 pandemic: a retrospective study.

BACKGROUND: Further understanding of the distribution and changing characteristics of dental diseases is of great significance for all dental emergency centers for strengthening the medical staff's treatment knowledge abilities and effective use of emergency resources in the face of public health emergencies involving highly infectious respiratory diseases. METHODS: The medical records of 4158 dental emergency patients in 2019 and 2020 were retrospectively analyzed and divided into pre-SARS-COV-2 group and SARS-COV-2 group according to time. The demographic data, date and time, diagnosis, and treatment methods of the two groups were statistically described, and the chi-squared test was used to analyze the differences. The medical records of 4158 dental emergency patients during the same period of two years in 2019 and 2020 were retrospectively analyzed and divided into SARS-COV-2 pre-group and SARS-COV-2 group according to time. The demographic data, date and time, diagnosis and treatment methods of the two groups were statistically described, and the chi-square test was used to determine the differences. RESULTS: During the SARS-COV-2 pandemic, the number of dental emergency visits increased by 29.7%. During the pandemic, males (n = 286, 58.1%) were more likely to visit dental emergency centers for trauma than females (n = 206, 41.9%) (P < 0.05); females (n = 242, 60.8%) were more likely to visit dental emergency centers for acute gingivitis and acute pericoronitis than males (n = 156, 39.2%) (P < 0.05). A major change in diagnosis was related to acute pulpitis (K04.0) and acute apical periodontitis (K04.4), which increased by 9.2%; acute gingivitis (K05.0) and acute pericoronitis (K05.2) increased by 3.5%; open wound of the lip and oral cavity (S01.5) decreased by 17.9%; other conditions (non-emergency diseases) increased by 6.8%, compared with the pre-SARS-COV-2 period. Among the treatment modalities, during the pre-SARS-COV-2 period, 304 patients (17.7%) received a prescription for antibiotics and analgesics, and 1485 (86.5%) received a prescription for local treatment. During the SARS-COV-2 period, 958 (39.2%) received a prescription for antibiotics and analgesics, and 1636 (67.0%) received a prescription for local treatment. CONCLUSION: SARS-COV-2 pandemic led to changes in the characteristics of dental emergency patients. Trauma, acute pulpitis, and acute periodontitis are the leading reasons patients refer to dental emergency centers. Dental emergency centers should optimize treatment procedures, optimize the staff, and reasonably allocate materials according to the changes to improve the on-site treatment capacity and provide adequate dental emergency care.

A Hypothesis and Pilot Study of Age-Related Sensory Innervation of the Hard Palate: Sensory Disorder After Nasopalatine Nerve Division.

BACKGROUND The nasopalatine nerve may be injured during extraction of teeth embedded in the anterior hard palate. The neural recovery process and its impact on sensation in the anterior hard palatal region are controversial. In our clinical practice, we noticed a distinct recovery process in children compared with adolescents or adults after surgery. We hypothesized that the sensory innervations of the anterior palate might shift during later childhood and pre-adolescence, which is due to the development of the nasopalatine nerve along with the maxillary growth and permanent teeth eruption. MATERIAL AND METHODS Forty patients (20 females and 20 males, mean age 11.8±2.2) with impacted supernumerary teeth in anterior palatine area were included into our study, and were divided into 3 groups according to their age. A 24-week follow-up was conducted and the sensation in the anterior hard palate region was examined at every check point. All the data were collected and analyzed by Kaplan-Meier analysis. RESULTS Fourteen children did not complain of any numbness immediately after anesthetization, and other children with sensory disorders had shorter healing periods compared to adolescent/adult patients. CONCLUSIONS The results indicated that the dominant nerve of the anterior hard palate region was dramatically changed from the greater palatine nerve to the nasopalatine nerve, which is important in deciding when to operate and in selection of anesthesia method.

Clinical considerations of emergent oral manifestations during pregnancy.

Pregnancy is a special period for developing and treating oral diseases. Oral emergencies during pregnancy need to be handled appropriately. Changes in the physiological environments and personal habits of pregnant women increase susceptibility to some oral diseases. However, clinical treatment strategies are limited due to the need to ensure the safety of pregnant women and fetuses. Pregnant women should obtain oral health knowledge and enhance their awareness. Dentists should adhere to the principle of "prevention before pregnancy, controlling symptoms during pregnancy, and treating diseases after pregnancy" for different pregnancy periods. They should also formulate appropriate treatment plans to control emergencies, prevent disease progression, and avoid harmful effects on pregnant women by using the safest, simplest, and most effective strategies that avoid adverse effects on fetuses. Pregnant women and dentists should combine prevention and treatment while collaborating in maintaining oral health during pregnancy. This article focuses on the principles of treatment during pregnancy, and the treatment timing, clinical management, and treatment strategies of different diseases causing oral emergencies during pregnancy are reviewed.

Could the pulp be preserved in tooth with root resorption caused by embedded tooth?

Background/purpose: At present, there are no recognized guidelines or consensus for the treatment strategy of the asymptomatic tooth with external root resorption caused by an embedded tooth (et-ERR). Most clinicians would like prophylactic or concomitant root canal therapy (RCT) along with the extraction of the embedded tooth. The purpose of this study was to report the prognosis of external root resorption (ERR) and investigate the possibility to preserve the vital pulp of ERR tooth. Materials and methods: The patients who had asymptomatic et-ERR teeth were included. After extraction of the embedded tooth, the clinical process, prognosis, and adverse events were observed, including symptoms, clinical, and radiographic examination throughout the follow-up period. Results: A total of four cases with special features were reported. Over a follow-up period of up to 12 months, on clinical examination, 3 ERR teeth preserved pulp vitality without additional intervention except for tooth extraction and have kept normal function free from any symptoms. Radiographic examination showed bone regeneration and recovery of periodontal tissue. While one case failed to keep the vital pulp and ended in intentional replantation. Conclusion: As to et-ERR, if the embedded tooth can be promptly extracted with a minimally invasive technique and effective infection control, the pulp vitality of the et-ERR tooth is likely to be preserved. In this situation, the preferred management of asymptomatic et-ERR tooth is just followed up without prophylactic RCT.

Analysis of dental clinic and dental chair distribution in Sichuan.

OBJECTIVES: To thoroughly understand the current dental chair equipment status of dental clinics in Sichuan Province and provide a reference for administrative departments. METHODS: Data were collected from a health administrative department and a regional social development yearbook. The number of existing dental clinics and dental chairs in Sichuan Province was investigated. RESULTS: In Sichuan Province, 7 103 dental clinics were determined to be equipped with 21 760 dental chairs. The Gini coefficients of per capita dental clinics in the province were 0.50, 0.22, and 0.06, and the Gini coefficients of per capita dental chairs were 0.68, 0.31, and 0.15; these coefficients had the same distribution as that reflected by the Lorenz curve. In consideration of geographic distribution, the Theil index for the distribution of dental clinics and dental chairs among cities and states were 0.690 7 and 0.822 3, respectively. The overall Theil index va-lues for the distribution of dental clinics and dental chairs in the province were 0.902 4 and 1.079 4, respectively. The difference in the distribution of dental clinics and dental chairs among cities and states in the province contributed 0.765 4 and 0.761 8 to the total difference, respectively. CONCLUSIONS: The allocation of oral health resources in Sichuan Pro-vince is relatively equitable in terms of population and economic distribution but uneven in geographical distribution.

Characteristics of Spatial Changes in Molars and Alveolar Bone Resorption among Patients with Loss of Mandibular First Molars: A CBCT-Based Morphometric Study.

OBJECTIVES: To investigate the characteristics of spatial changes in molars and alveolar bone resorption among patients with loss of mandibular first molars. METHODS: A total of 42 CBCT scans of patients with missing mandibular first molars (3 males, 33 females) and 42 CBCT scans of control subjects without loss of mandibular first molars (9 males, 27 females) were evaluated in this cross-sectional study. All images were standardized using the mandibular posterior tooth plane with Invivo software. The following indices regarding alveolar bone morphology were measured, including alveolar bone height, bone width, mesiodistal and buccolingual angulation of molars, overeruption of maxillary first molars, bone defects, and the capability of molar mesialization. RESULTS: The vertical alveolar bone height in the missing group was reduced by 1.42 ± 0.70 mm, 1.31 ± 0.68, and 1.46 ± 0.85 mm on the buccal, middle, and lingual side, respectively (no differences among the three sides; p > 0.05). Alveolar bone width was reduced the greatest at the buccal CEJ level and the least at the lingual apex level. Mandibular second molar mesial tipping (with mean of the mesiodistal angulation = 57.47 ± 10.34°) and lingual tipping (with mean of the buccolingual angulation = 71.75 ± 8.34°) were observed. The mesial and distal cusps of maxillary first molars were extruded by 1.37 mm and 0.85 mm, respectively. Buccal and lingual defects of alveolar bone occurred at the CEJ, mid-root, and apex levels. Through 3D simulation, the second molar cannot be successfully mesialized into the missing tooth position, and the difference between the available and required distances for mesialization was the greatest at the CEJ level. The duration of tooth loss was significantly correlated with the mesio-distal angulation (R = -0.726, p < 0.001), buccal-lingual angulation (R = -0.528, p < 0.001) and the extrusion of the maxillary first molar (R = -0.334, p < 0.05). CONCLUSION: Both vertical and horizontal resorption of alveolar bone occurred. Mandibular second molars exhibit mesial and lingual tipping. Lingual root torque and uprighting of the second molars are needed for the success of molar protraction. Bone augmentation is indicated for severely resorbed alveolar bone.

Prognosis of Second Molars with External Root Resorption Caused by Adjacent Embedded Third Molars.

INTRODUCTION: This prospective study was designed to determine the prognosis of second molars with external root resorption (ERR-M2s) caused by embedded third molars (EM3s) following EM3 removal and explore related predictors. METHODS: This study consecutively enrolled 58 participants who had asymptomatic second molars with apical external root resorption caused by EM3s. EM3s were extracted, and follow-up examinations were conducted at 1 week, 4 weeks, and 6 months. The primary outcome was prognosis of ERR-M2s after third molar extraction without any further intervention, as assessed via clinical and radiographic examinations. Potential predictors (sex, age, number of roots, EM3s position, type and degree of external root resorption) of prognosis were analyzed via univariable and multivariable analyses. RESULTS: A total of 63 ERR-M2s from 58 patients (16 males and 42 females; 19-57 years of age) were evaluated. At the last follow-up, 56 teeth (89%) remained asymptomatic and normal response to heat and cold tests. According to univariable analyses, ERR-M2s were more likely to remain normal response to heat and cold tests in younger patients. In the multivariable analysis, older age (odds ratio, 1.118; 95% confidence interval, 1.026-1.219; P < .05) and the type of all roots affected (odds ratio, 0.073; 95% confidence interval, 0.007-0.754; P < .05) were significantly associated with poor prognosis. CONCLUSIONS: Asymptomatic ERR-M2s have a high probability of remaining normal pulp without further intervention after EM3 extraction, especially in younger patients. No intervention except follow-up and observation is necessary.

Orthodontic traction of an impacted maxillary third molar through a miniscrew-anchored cantilever spring to substitute the adjacent second molar with severe root resorption.

BACKGROUND: An orthodontic traction technique with a miniscrew-anchored cantilever spring was used for the traction of a deeply impacted maxillary third molar to substitute its adjacent second molar with severe root resorption. CASE DESCRIPTION: A 30-year-old woman sought multidisciplinary treatment planning for a second molar with severe root resorption caused by a deeply impacted third molar. Panoramic radiographs and cone-beam computed tomographic images showed that the third molar was located on the apical and palatal side of the second molar and that the second molar had severe root resorption. The second molar was removed, and the impacted third molar was orthodontically tractioned occlusally with the aid of a miniscrew-anchored cantilever spring. After 12 months of orthodontic treatment, the maxillary left third molar was successfully tractioned occlusally and well aligned with adjacent teeth for the substitution of the second molar. The patient was satisfied with the treatment outcome. PRACTICAL IMPLICATIONS: A palatal miniscrew-anchored cantilever spring is an effective and viable technique for the orthodontic traction of deeply impacted third molars to substitute second molars with severe root resorption.

Mesenchymal stem cells transduced by stromal cell-derived factor-1α augment ischemic free flaps' survival.

Mesenchymal stem cells (MSCs) have the potential for differentiating into vascular endothelial cells. Stromal cell-derived factor-1α (SDF-1α) plays an important role in neovascularization of ischemic flaps. The authors evaluated the feasibility of applying MSCs transduced by SDF-1α gene to the treatment of early and partial ischemic free flaps survival. MSCs were isolated from Lewis rats and cultured in vitro. Recombinant adenovirus encoding SDF-1α gene (Ad-SDF-1α) was transduced into the MSCs. Lewis rats that underwent epigastric free flaps based on medial and lateral branches of superficial inferior epigastric vessels and femoral vessels were equally randomized into 4 groups, and injected with Ad-SDF-1α-transduced MSCs, MSCs, Ad-SDF-1α, and normal saline, respectively. Gene transduction, flaps survival, neovascularization, and expression level of SDF-1a protein were detected. The results showed that Ad-SDF-1α-transduced MSCs expressed higher SDF-1α both in vitro and in vivo, yielded more survival area, and resulted in higher neovascularization than any other groups. Interestingly, the necrotic sites of all free flaps were in the proximal end rather than in the distal end. In conclusion, Ad-SDF-1α-transduced MSCs can increase neovascularization of early and partial ischemic free flaps and augment the surviving areas.

Orthodontic extraction of a high-risk impacted mandibular third molar contacting the inferior alveolar nerve, with the aid of a ramus mini-screw.

An orthodontic extraction technique with a ramus mini-screw was used to remove a deeply impacted mandibular third molar contacting the inferior alveolar nerve, avoiding damage to the inferior alveolar nerve and relieving postsurgery inflammation. Case presentation: A 24-year-old man was required to extract impacted third molars for orthodontic treatment. Panoramic radiographs and CBCT images showed that his mandibular left third molar penetrated into the inferior alveolar nerve canal and a distomolar was inverted and impacted distally to the third molar. The distomolar was directly removed and the impacted third molar was extruded with the aid of a ramus mini-screw. After 4 months of traction, the mandibular left third molar was successfully moved away from the inferior alveolar nerve canal. No nerve injury occurred after the surgical extraction and the patient was very satisfied with the treatment outcome. Conclusion: Orthodontic extraction, with the aid of ramus mini-screws, is a safe, effective, and efficient technique for the removal of high-risk impacted molars contacting the inferior alveolar nerve. (Quintessence Int 2021;52:538-546; doi: 10.3290/j.qi.b1244345).

Distal-triangular flap design for impacted mandibular third molars: a randomized controlled trial.

OBJECTIVES: This prospective study was performed to evaluate whether the distal-triangular flap was a practical alternative surgical approach for extracting mandibular third molars. METHODS: Sixty participants with impacted mandibular third molars were randomly divided into three groups: group A, distal-triangular flap; group B, Szmyd flap; and group C, envelope flap. The impacted third molars were extracted by the corresponding flapping method. During a three-month follow-up observation after the extraction, the postoperative pain, swelling, mouth opening, and periodontal status were recorded and analyzed by ANOVA and chi-square tests. RESULTS: The 60 participants had successful extraction and 3-month follow-up observation. No participant suffered from postoperative infections, lower lip disorder, or tongue sensory disorders. No statistical differences were found in the postoperative symptoms and signs of the three flap designs, such as postoperative pain, swelling, mouth opening, and periodontal status (P>0.05). CONCLUSIONS: The distal-triangular flap was as safe and reliable as the Szmyd and envelope flaps but more advantageous because of its convenient operative field exposure and low requirement for the patient's mouth opening. Thus, the distal-triangular flap is one of the alternative flap options for extracting impacted mandibular third molars.

[Clinical study of age-related sensory innervation of the anterior hard palate].

OBJECTIVES: The present study aimed to explore the innervation of the anterior hard palatine and its relationship with individual development stage. Specifically, the effects of anesthesia on patients of different ages were observed, and neurodevelopment in the maxillofacial region was invesitgated. References that are helpful in selecting local anesthesia were provided. METHODS: A total of 182 patients with mixed dentition were randomly divided into the nasopalatine nerve block and greater palatine nerve block groups. Then, 219 patients with permanent dentition were divided into an adolescent group (13-18 years old) and adult group (over 19 years old), all of whom underwent bilateral greater palatine nerve block. Palatal mucosal pain sensation was tested pre- and post-anesthesia with Von Frey hairs. RESULTS: Among the children with mixed dentition, bilateral greater palatine nerve block tended to result in better anesthetic effects than nasopalatine nerve block (P<0.05), except in the incisive papilla. No difference in anesthetic effect was observed between adolescents and adults (P>0.05). The bilateral greater palatine nerve block was more effective in inducing an anesthestic effect in the anterior hard palatine in mixed dentition than in permanent dentition (over 13 years old; P<0.05). CONCLUSIONS: The sensation of the anterior hard palatine seems mainly dominated by the greater palatine nerve until mixed dentition and gradually shifted to the nasopalatine nerve in conjunction with maxillary development and tooth replacement. Hence, the innervation of the anterior hard palatine induce a secondary development during the development of the maxilla.

A novel theranostic nanoplatform for imaging-guided chemo-photothermal therapy in oral squamous cell carcinoma.

Oral squamous cell carcinoma (OSCC) is highly malignant and invasive, and current treatments are limited due to serious side effects and unsatisfactory outcomes. Here, we reported the terbium ion-doped hydroxyapatite (HATb) nanoparticle as a luminescent probe to encapsulate both the near-infrared (NIR) photothermal agent polydopamine (PDA) and anticancer doxorubicin (DOX) for imaging-guided chemo-photothermal therapy. The morphology, crystal structure, fluorescence, and composition of HATb-PDA-DOX were characterized. HATb-PDA showed a high DOX loading capacity. A theranostic nanoplatform showed pH/NIR responsive release properties and better antitumor outcomes in OSCC cells than monomodal chemotherapy or photothermal therapy, while keeping side effects at a minimum. Also, the luminescence signal was confirmed to be tracked and the increase of the red/green (R/G) ratio caused by the DOX release could be used to monitor the DOX release content. Furthermore, HATb-PDA-DOX plus NIR treatment synergistically promoted in vitro cell death through the overproduction of reactive oxygen species (ROS), cell cycle arrest, and increased cell apoptosis. Overall, this work presents an innovative strategy in designing a multifunctional nano-system for imaging-guided cancer treatment.

Anterior skull base reconstruction with galeal-frontalis-pericranial flap based on temporalis myofascial flap.

Such a giant anterior skull base mucocele involving the orbito-ethmoido-maxillo-fronto sinuses is a rare case. This patient complained of a right orbital mass for 18 years, and he was recommended to our hospital for treatment. His history, physical examination, laboratory study results, diagnosis, and treatment are reported in detail. In conclusion, we show that modified transcranial pathway and ingenious assistant incision can get the utmost exposure and can obtain a satisfactory aesthetic result and that anterior skull base reconstruction with the galeal-frontalis-pericranial flap based on the temporalis myofascial flap for the first time can successfully prevent life-threatening complications from happening.

[Strategy of dental clinics to cope with the epidemic period of infectious diseases based on the experience of corona virus disease outbreak].

The outbreak of corona virus disease (COVID-19) has raised concerns among dentists to develop strategies to prevent infection of dental equipment, materials, and patients during an epidemic period. Strategies following the National Laws and Standards of China and local standards of several provinces for controlling cross-infection and instituting protective measures for medical staff in dental clinics during an epidemic period are discussed. A proposal is put forth for dental clinics that will face similar situations in the future. Further research is warranted to address potential problems that will be encountered under such dire circumstances.

Metastatic tumors to the oral and maxillofacial region: a retrospective study of 19 cases in West China and review of the Chinese and English literature.

PURPOSE: The aim of this article was to obtain an overview of metastatic tumors to the oral and maxillofacial (OMF) region, especially the differences in the constituent ratios of primary cancers between the United States and China. PATIENTS AND METHODS: Clinical findings of 19 cases encountered in West China Hospital of Stomatology were summarized and the English and Chinese literature were reviewed and analyzed. The main clinical features of OMF metastases were summarized, with an emphasis on primary cancers' constituents. RESULTS: The lung, breast, kidney, liver, and prostate were the top 5 common primary sites of cancer. However, there was a significant difference in the primary cancers' constituents between United States and China (P < .001). The breast, kidney, prostate cancers, and melanoma of skin were more frequent primary cancers in United States than in China, whereas that of the lung, thyroid, liver, esophagus, and the stomach were more common in China than in United States. The proportions of the OMF metastatic lesions originating in the lung, kidney, liver, thyroid, and esophagus in all OMF metastatic tumors were higher than the corresponding primary cancers' prevalent proportions. CONCLUSIONS: The frequency of developing OMF metastasis is not always consistent with primary cancers' prevalence, which suggests that different cancers have different potentiality to develop OMF metastasis. Cancers of the kidney, liver, lung, thyroid, and esophagus were more likely to spread to the OMF region. In general screening of primary cancer, it would be helpful to take into account the metastatic potentiality of different cancers and primary cancers' prevalence in different countries in the case of occult primary.

[Prognosis of teeth with external root resorption caused by adjacent impacted teeth].

OBJECTIVE: This study aimed to investigate the prognosis of permanent teeth with external root resorption (ERR) caused by adjacent impacted teeth. METHODS: A total of 75 ERR teeth (permanent teeth) caused by adjacent impacted teeth of 63 patients were included. The prognosis of ERR teeth was analyzed followed by minimally invasive extraction of the adjacent impacted teeth. The time of follow-up was six months. The relationship between prognosis of ERR teeth and patients' age, gender, root number, type of root resorption and degree of root resorption were analyzed. RESULTS: In the 75 ERR teeth, 67 teeth (89.3%) did not show pulpitis symptoms. The clinical outcome was found to be related with age (r=0.330, P<0.05), whereas no relationships with gender, root number, as well as type and degree of root resorption were observed (P>0.05). Pulpitis symptom was not found in ERR teeth of patients under 30 years old. CONCLUSIONS: For ERR teeth caused by adjacent impacted teeth, keeping the pulp vital after surgical removal of impacted teeth is highly probable. Post-operative follow-up instead of preventive root canal therapy of ERR teeth is recommended.