Effect of buccal fat autotransplantation on improving the alveolar socket bone regeneration: An in-vivo study.

Background: There are various materials used for socket preservation following dental extraction. The aim of the present animal study was to histologically investigate the efficacy of buccal fat autotransplantation on alveolar bone regeneration following dental extraction. Study design: In this prospective, double-blind laboratory experiment with a split-mouth design, 16 mandibular second premolar teeth in eight beagle dogs were extracted, and half of the extraction sockets were randomly filled using buccal fat autotransplantation. Other samples were left untouched to heal normally by the formed blood clot. Buccal fat autotransplantation was the primary predictor variable, and the type and amount of newly formed bone were the primary outcome variables. Assessment methods were the H & E coloring technique and histomorphometric evaluation. The significance level was set at 0.05, and data was subjected to Chi-Square and Wilcoxon signed-rank tests using SAS statistical software version 9.4. Results: From the total number of 16 samples in 8 dogs, 50% of the samples in the intervention group represented inflammation with lower intensity compared to 33% in the control group; however, this difference was not considered statistically significant (Chi-Square test, P-value = 0.55). Wilcoxon test results showed no statistically significant difference between the two groups regarding the mean amount of total bone formation (Z = 0.00, P-value = 1.00). Conclusion: It was inferred from the outcomes of the present study that when compared to the normal healing of the socket, buccal fat autotransplantation did not represent with superior outcome concerning the socket bone regeneration.

Evaluating the Clinicopathologic Parameters of Tongue Squamous Cell Carcinoma based on its Local Distribution.

Background: Oral squamous cell carcinoma (OSCC) is one of the most common oral lesions and the tongue is one of the most common areas involved. The aim of this study was to evaluate the clinicopathologic feature of tongue SCCs based on its local distribution. Materials and Methods: In this cross-sectional study, clinical data such as age, gender, location, and clinical appearance were extracted from the archives of the Oral Pathology Department, Isfahan Dental School, registered with a definitive diagnosis of tongue SCC during 2005-2019. Then, 34 specimens were selected for histopathological evaluation in a simple random way. The histopathologic slides were examined to determine the grade of tumor malignancy. The data were entered into SPSS23 software and analyzed by Chi-square, Fisher exact, One-way ANOVA, and Non-parametric tests. P value <0.05 was considered significant. Results: Of the 275 OSCCs, 68 samples were tongue SCC. The mean age of patients was 61.7 ± 15 and 61.8% were women. The most common clinical manifestations were exophytic lesions (42.6%) and the most common site was the lateral border of the tongue (36.8%). The results did not show a significant relationship between the clinicopathologic feature including mean age (p = 0.766), gender (p = 0.338), clinical presentation (p = 0.434), grade of malignancy (p = 0.763) and location. But, among the histopathological parameters, the pattern of invasion (p = 0.047) was significantly associated with the local distribution. Conclusion: Given that most OSCCs had moderate differentiation of malignancy, identification of clinical features is needed. Attention to the pattern of invasion and location on the tongue can be effective in determining the therapeutic approach.

Evaluation of Dentists' Attitudes Towards Principles of Professional Ethics.

OBJECTIVE: The aim of this research was to investigate attitudes towards principles of professional ethics (PPE) amongst Iranian dentists working in Isfahan, Iran. METHODS: This pilot cross-sectional study was conducted amongst 273 dentists in Isfahan, Iran. A validated, comprehensive questionnaire including principles of respect for patient autonomy, nonmaleficence, beneficence, and justice was used to evaluate dentistry professional ethics aspects. Age, gender, marital status, type of graduate university, level of education, specialised field of study, work experience, workplace, and participation in ethics workshops and courses were registered from participants. Total and domains scores of used questionnaires were calculated and compared across categories of study participants' characteristics. RESULTS: Mean ± SD age of participants was 35.4 ± 10.7 years, and 57% were female; about 73% graduated from Isfahan University of Medical Sciences, and 65% were general dentists. The attitude total score of dentists towards PPE was 133.02 ± 13.16. Mean total score of the questionnaire and its domains was different significantly (P < .05) across categories of level of education, marital status, and passing the ethical courses. CONCLUSIONS: The attitude of dentists towards PPE was rated at a good level. However, improvement in attitudes of some specific subgroups such as general dentists and newly graduated ones is needed. Conducting specific workshops about professional ethics and incorporating these principles into university curricula can be beneficial.

The comparative evaluation of CK17 expression in histologic and cytological sections of oral squamous-cell carcinoma using immunohistochemistry.

BACKGROUD: Squamous-cell carcinoma of the mouth accounts for 90% of all oral cancers and despite advances in treatment methods, its 5-year survival rate is reported to be about 68%. This is due to the late diagnosis of the disease and its resistance to radiotherapy and chemotherapy treatments. One of the methods for diagnosing oral lesions is exfoliative cytology, which is a noninvasive method and can be easily carried out in a dental office. AIM: The purpose of this study is to find a method that in addition to being fast, accurate and less aggressive has high value and a good degree of accuracy for diagnosis of oral squamous-cell carcinoma. MATERIALS AND METHODS: In this descriptive-analytical study, 14 patients who were diagnosed with oral squamous-cell carcinoma and 14 specimens from exfoliative cytology of the same tissue before surgery were examined. Immunohistochemically stained specimens were examined by two pathologists simultaneously. Next, five nonoverlapping sections with magnification (×400) and the number of cells stained with the cytokeratin marker 17 are counted and the average percentage of each slide is determined. One-sample t-test is used to analyze the data and significance level in tests is considered 0.05. RESULTS: In examining the diagnostic value of cytology, we concluded that out of 280 affected cells, 211 cells were stained. Therefore, the sensitivity of cytology in the diagnosis of squamous-cell carcinoma of the mouth is 75.4%. In other words, cytology correctly identifies 75.4% of affected cells as affected. Also, the positive predictive value of cytology was 100%.

Effect of Duration of Root Canal Infection on the Ability of Dentin-Pulp Complex Regeneration of Immature Permanent Teeth: An Animal Study.

INTRODUCTION: Persistent infection is always considered the most important reason for the failure of dentin-pulp complex regeneration. The present study aimed to evaluate the effect of the duration of root canal infection (from 1-12 weeks) on the ability of dentin-pulp complex regeneration. METHODS: In this animal study, 64 roots of immature premolar teeth of 4 dogs were randomly divided into the following groups: the positive control group, 8 root canals treated with the regenerative endodontic procedure (REP); the negative control group, 12 infected root canals; the intervention groups, 36 root canals infected with supragingival plaque (1, 3, 6, and 12 weeks) and treated with REP; and an additional positive control group, 8 normal roots. After 3 months, the teeth were investigated by radiographic images and immunohistochemical staining (CD31, CD34, and S100 markers). In addition, DSPP gene expression was assessed using a real-time polymerase chain reaction technique. RESULTS: Based on radiologic evaluation among the intervention groups, the highest root canal development (length and width) occurred in the intervention group of 1 week, and the lowest radiologic results were in the intervention groups of 6 and 12 weeks (1-way analysis of variance, P-value < .05). There was a significant difference between the groups in terms of CD31, CD34, S100, and DSPP expression percentage (1-way analysis of variance, P-value < .05); the highest and lowest expression percentages belonged to the 1- and 12-week groups, respectively, among the intervention groups. CONCLUSIONS: This study demonstrated that long root canal infection decreased the ability of the body to regenerate the dentin-pulp complex.

Granular cell odontogenic tumor: report of a rare case and a review of literature.

BACKGROUND: Granular cell odontogenic tumor (GCOT) is a rare neoplasm with about 45 cases reported in the literature. It usually occurs in the posterior mandible of middle-aged women. CASE PRESENTATION: We report a case of asymptomatic GCOT in the posterior mandible of a 28 years old female and provide a literature review of GCOT cases. Some unusual features such as root resorption, displacement of inferior tooth canal, and multilocular appearance were considerable in this case. CONCLUSIONS: Complete surgical excision of the lesion was beneficial for the patient.

Histological assessment of the local effect of different concentrations of aminoguanidine hydrochloride on bone healing in rats.

BACKGROUND: Nitric oxide (NO) has several functions in bone healing and affects bone metabolism. Selective inducible NO synthase (iNOS) inhibitors can be used to assess the efficacy of NO for healing of bone defects. This study sought to assess the local effect of different concentrations of aminoguanidine hydrochloride (AG), a selective iNOS inhibitor, on bone healing in rats. MATERIALS AND METHODS: In this animal experimental study, 72 rats were divided into six groups of control, placebo, 5% AG, 10% AG, 15% AG, and 20% AG. A bone defect measuring 5 mm × 5 mm was created in the femur. The defect remained empty in the control group. In the placebo group, neutral gel was placed in the bone defect, and in the remaining four AG groups, different concentrations of AG were applied to the defects. Bone healing was assessed histologically. The healing score in the six groups was analyzed by the Kruskal-Wallis test. A P < 0.05 was considered statistically significant. RESULTS: The healing score in 20%, 15%, 10%, and 5% AG groups was significantly higher than that in the neutral gel and control groups (P < 0.01). Among the four groups of AG, 20% concentration showed better results, but the difference was not significant. CONCLUSION: Four concentrations of AG caused greater bone healing compared to the other two groups. Selective iNOS inhibitors such as AG can be used to promote local bone healing.

Improving pulp revascularization outcomes with buccal fat autotransplantation.

Several techniques have been introduced to improve the pulp revascularization outcomes. The use of the tissue graft can create more practical tissue regeneration, provide vascular supply, and enhance tissue healing. The aim of the present study was to investigate the histologic and molecular outcomes of pulp revascularization with buccal fat autotransplantation. Fifty-six open apex roots from four dogs aged 4-6 months were randomly allocated to five groups of endodontic regeneration models: Group 1 (negative control, n = 4); Group 2 (control and without intervention, n = 4); Group 3 (blood clot, n = 16); Group 4 (buccal fat autotransplantation, n = 16); and Group 5 (blood clot plus buccal fat autotransplantation, n = 16). After 3 months, the extracted dog teeth were analyzed by histological and immunohistochemical techniques. Furthermore, real-time quantitative polymerase chain reactions were implemented to assess the gene expression profiles of dentin sialophosphoprotein (DSPP), dentin matrix protein (DMP), collagen I (COL1), and alkaline phosphatase (ALP) on regenerated tissue in the root canals. There were no significant differences in the severity of inflammation and necrosis between intervention groups. Immunohistochemical analysis showed significant differences among the study groups in expression level of extracellular glycoproteins such as fibronectin, laminin, and tenascin C. Group 5 showed an increase in the expression of DMP1 and COL1 genes. The expression of DSPP gene increased significantly in Group 4. The expression of ALP gene increased significantly in Group 3. Using this procedure may open new fields of research for regenerative endodontic procedure in which tissue autotransplant, particularly adipose tissue, may improve the outcomes of pulp revascularization.

Retro MTA and tricalcium phosphate/retro MTA for guided tissue regeneration of periodontal dehiscence defects in a dog model: a pilot study.

OBJECTIVES: Retro MTA is a fast setting Calcium silicate cement used in endodontic regeneration procedures in recent years. Beta-tricalcium phosphate (ß-TCP) is another common biomaterial used for bone augmentation procedures. The present pilot study was undertaken to evaluate and compare the efficacy of Retro MTA and a mixture of Retro MTA / ß-TCP for periodontal tissue regeneration. MATERIALS AND METHODS: In 4 beagle dogs, periodontal dehiscence type defects were created. In each side, one dehiscence defect was left empty as a control site and three treatment modalities were randomly applied for the others: Retro MTA covered with a collagen membrane, Retro MTA + ß-TCP covered with a membrane and covering the defect with a membrane without any bone augmentation. After 8 weeks Animals were sacrificed and Histomorphometric and histologic analysis were conducted. RESULTS: Histologic analysis showed more cementum formation for both Retro MTA+ ß-TCP (3.74 ± 0.34 mm) and Retro MTA group (3.24 ± 0.56 mm) compared to control group 1 (1. 15 ± 0.45 mm) and control group 2 (0.78 ± 0.65 mm). Formation of newly formed bone and cementum in the experimental groups were significantly higher as compared to the control groups (P < 0.0001). CONCLUSIONS: Retro MTA or Retro MTA+ ß-TCP covered with a collagen membrane resulted in regeneration of periodontal tissues. However, Retro MTA+ ß-TCP showed tendency towards better results than the use of Retro MTA alone.

Systemic supplement with resveratrol increased bone formation in rats' alveolar socket / Aumento de la formación ósea en el hueso alveolar de rata con suplemento sistémico con resveratrol

Resveratrol in cell culture media increases osteoblastic markers. Also results from previous studies provide evidence for resveratrol positive effects on bone healing and bone production. In this preclinical study we investigated bone healing in rats by resveratrol systemic application. 30 Wistar male rats were divided into two groups (study group and control group). At first, maxillary second molars of rats were extracted. The rats were kept in laboratory for next 28 days. Study group received resveratrol 20 mg/kg by abdominal injection every day. The control group received placebo in the same manner that study group. Rats were sacrificed after 28 days and bone samples were collected from center of maxillary second molar socket. Samples were evaluated histologically for new bone formation, inflammation, necrosis, fibrosis and foreign body reaction. The mean difference of new bone formation in control group (28.30 %) and study group (45 %) were statistically significant (P=0.014). There were no significant differences in inflammation, fibrosis, necrosis and foreign body reaction (P>0.05). Resveratrol has positive effects on bone healing but more evidence needed from more clinical and animal studies.

El resveratrol en los medios de cultivo celular aumenta los marcadores osteoblásticos. Los resultados de estudios anteriores proporcionan evidencia de efectos positivos del resveratrol sobre la curación ósea y la producción ósea. En este estudio preclínico, investigamos la curación ósea en ratas mediante la aplicación sistémica de resveratrol. Se dividieron 30 ratas macho Wistar en dos grupos (estudio y control). Inicialmente se extrajeron los segundos molares maxilares de las ratas y los animales se mantuvieron en el laboratorio durante los siguientes 28 días. El grupo de estudio recibió todos los días resveratrol 20 mg/kg por inyección abdominal . El grupo control recibió placebo de la misma manera que el grupo estudio. Las ratas fueron sacrificadas después de 28 días y se recogieron muestras de hueso del centro del segundo molar maxilar. Las muestras se evaluaron histológicamente para la formación de hueso nuevo, inflamación, necrosis, fibrosis y reacción de cuerpo extraño. La media de formación de hueso nuevo en el grupo control (28,30 %) y en el grupo estudio (45 %) fueron estadísticamente significativas (P=0,014). No hubo diferencias significativas en la inflamación, fibrosis, necrosis y reacción al cuerpo extraño (P>0,05). El resveratrol tiene efectos positivos sobre la curación de los huesos, pero aún es necesario realizar más pruebas de estudios clínicos, como también en animales.

Histological Comparison of New Bone Formation Using Amnion Membrane Graft Versus Resorbable Collagen Membrane: An Animal Study.

The purpose of this article was to evaluate the bone induction effects of an amnion membrane-protected graft compared with a collagen membrane-protected graft in the repair of tibial bony defects in dogs. This study was performed using the tibial bone of dogs. After the removal of periosteum, similar holes were made with a 16-mm trephine drill (38 holes in total). For the study group, 10 holes were covered by absorbable collagen and 16 holes by amniotic membrane. In the control group, 12 holes were made and covered by the overlying soft tissue. Tibial bones were exposed after 6 and 12 weeks, and the samples were harvested and histologically processed. New bone formation was evaluated by histomorphometric study. Four Iranian mixed dogs older than 1.5 years were included in this study. The new bone formation was less in the control group when compared with the collagen group ( P = .863). The collagen group showed less bone formation than the amnion group ( P = .194), but this difference was not significant. However, bone formation in the amnion group was significantly more than in the control group ( P = .050). Using the amniotic membrane appears to accelerate bone formation in guided bone regeneration. However, further studies should investigate its clinical impact on bone healing.

A Comparative Study of the Perspectives of General and Oral and Maxillofacial Pathologists about the Rate and Value of Second Referral in Assessment of Oral and Maxillofacial Pathologic Lesions.

The main purpose in the practice of pathology is to provide an accurate diagnosis. Second referral and reassessment by a second pathologist significantly cause diagnostic errors, help to make an accurate diagnosis, and improve patient management. This study was aimed to assess the general perspectives of general and oral and maxillofacial pathologists in Iran on second referrals. In this cross-sectional, descriptive-analytical study, a 20-item questionnaire on second referrals was used to assess the general and oral and maxillofacial pathologists' perspective in Iran. The obtained data were analyzed by chi-square and Mann-Whitney tests (α = 0.05). A total of 64 questionnaires from general and 45 questionnaires from oral and maxillofacial pathologists were collected. The findings showed 70.9% of pathologists were in favor of seeking a second opinion when faced with diagnostic challenges. Significant differences were found between the oral and general pathologists in terms of the most challenging oral and maxillofacial lesions (p value < 0.001). In total, 74.8% of pathologists suggested second opinion to be useful and productive. Both groups of pathologists approved of the second referral. However, this pattern is still different, and it is possible to improve the referral rate among both groups and to enhance the knowledge of general pathologists about second referral to oral and maxillofacial pathologists.

Orofacial Pathological Lesions in Children and Adolescents: A 25-year survey in Iran.

STATEMENT OF THE PROBLEM: Oral pathological conditions presented in children are various and often different from those of adults. There is considerable variation in the prevalence of these lesions among different regions of the world. PURPOSE: The aim of this study was to assess the frequency and clinical-pathological features of oral lesions diagnosed in children and adolescents throughout 25 years in an oral pathology department. MATERIALS AND METHOD: This cross-sectional study was conducted in the Department of Oral and Maxillofacial Pathology at Dental School of Isfahan University of Medical Sciences. All the medical reports and biopsy files of the patients aged <18 years that were diagnosed during January 1990 and December 2015 were retrieved. The data regarding histopathologic diagnosis, site of lesions, and date of diagnosis and demographic characteristics of patients were elicited. The lesions were categorized based on their origin and age group of the patients. Descriptive statistics were used as appropriate. The critical level of significance was set at p< 0.05. RESULTS: 1267 lesions were recorded. The mean age of the samples was 12.5±3.9. Of lesions, (408, 49.3%) were in posterior area. The most common lesions were odontogenic cysts (416, 32.9%) and reactive lesions (317, 25.1%) and the least common lesions were allergic and immunologic disorders (2, 0.2%). In age groups of 7-12 and 13-18 years, odontogenic cysts [(208, 38.1%), (198, 31.4%)] and reactive lesions [(143, 26.3%), (147, 23.3%)] were the most common lesions, respectively. During the 25 years of survey, the prevalence of pulp and periapical disease increased (p <0.001), that of bone pathology decreased (p< 0.05) and trend of other lesions did not significantly change over this time. CONCLUSION: The most frequent lesions were odontogenic cysts and reactive lesions. The prevalence of lesions was not changed dramatically during the 25 year. The frequency of oral lesions in Isfahan province (in Iran) is different from other regions in the world and even, to some extent, different from other regions in Iran, which is in agreement with the hypothesis of geographical distribution of these lesions.

A case of central mucoepidermoid carcinoma associated with dentigerous cyst.

Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland neoplasm. Central MEC (CMEC) is a rare primary intraosseous bony lesion with an incidence of 2%-4.3% of all MECs reported. In this article, we present a rare case of a CMEC in the anterior region of maxilla at a 43-year-old female patient that was arising from a dentigerous cyst. CMECs are extremely rare tumor. They are usually low-grade lesions with favorable prognosis. Odontogenic cysts are one of the origins of this lesion. Treatment of impacted tooth is necessary in the early stage for prevention of this neoplasm.

Selective nitric oxide synthase inhibitor promotes bone healing.

BACKGROUND: Nitric oxide (NO) has many functions in wound healing and bone metabolism. This study sought to assess the local effect of aminoguanidine (AG), a selective inducible NO synthase (iNOS) inhibitor, on the rate of bone healing. MATERIALS AND METHODS: This experimental interventional study was conducted on 36 rats, which were randomly divided into three groups of control, placebo, and AG. Bone defects measuring 5 mm × 5 mm were created in the femur. In control group, bone defects remained empty. A placebo gel was applied to defects in the placebo group. AG gel was placed in bone defects in AG group. New bone formation and healing were assessed using histological and histomorphometric analyses. The healing score and the percentage of new bone formation (total bone mass, immature bone, and mature bone) were compared among the three groups using the Kruskal-Wallis test and analysis of variance, respectively. A P < 0.05 was statistically significant. RESULTS: The mean healing score in AG group (3.17 ± 0.577) was significantly higher than that in control (2.67 ± 0.49) and the placebo (2.58 ± 0.515) groups (P = 0.036). The percentage of new mature (lamellar) bone in AG group (22.06 ± 1.90) was significantly higher than that in control (20.94 ± 2.03) and the placebo (20.53 ± 1.20) groups (P = 0.008). CONCLUSION: The rate of bone healing was faster in the AG compared to the other two groups. Local application of selective iNOS inhibitors like AG may be efficient as an adjunct in the clinical setting where local bone formation is required.

Rare and Extensive Malignant Melanoma of the Oral Cavity: Report of Two Cases.

Primary oral melanomas are uncommon malignant neoplasm of melanocytes origin. The most common site of oral melanoma is maxillary gingiva and hard palate. Oral mucosal melanoma exhibit a pathobiological behavior and clinical features different from cutaneous melanomas. Oral melanomas are often clinically silent which may consequently result in delayed diagnosis; thus, making the prognosis extremely poor. This case report presents clinical, histopathological and immunohistochemical features of two cases of advanced oral melanoma, one pigmented or melanotic melanoma in a 46-year-old female and another amelanotic melanoma in a 59-year-old male patient, with chief complaint of swelling in oral mucosa. Most oral melanomas are usually asymptomatic lesions with quick growing. Thus, the most cases are detected in late stage of diagnosis. Early diagnosis with careful examination by dentists, and early biopsy of pigmented and suspicious non-pigmented lesions would have an imperative role in more survival rate and better prognosis.

Assessment of the quality of life of the patients with treated oral cancer in Iran.

PURPOSE: Oral cancer diagnosis and treatment could influence the well-being of patients. The aim of this study was to assess the quality of life (QOL) of oral cancer patients after their treatments. METHOD: In this descriptive-analytical study, all oral cancer patients' records were retrieved from the archives of the oral pathology departments of Isfahan dental school and Sayed-al-Shohada from 2004 to 2015. Telephone interviews were conducted to collect data using the short form 36 (SF-36) and Head and Neck (H&N35) questionnaire. Demographic information of participants as well as tumor-related information, including last treatment date, therapy method, differentiation grade (mild, moderate, poorly differentiated), primary place of tumor in the mouth, and history of recurrence were recorded. Analysis of variance (ANOVA), t test, and Pearson and Spearman correlation coefficients were used for data analysis (α = 0.5). RESULTS: From 223 registered patients, 73 were available. Most of the participants were in the age group of 29-87 years (61 ± 16.3). The mean of SF36 and H&N QOL was 63.77 ± 23.44 (from 100) and 63.7 ± 15.36 (35-140). Females and those receiving combined therapy had lower QOL status. Participants who received their last treatment earlier had a significantly better QOL for both scores (P value < 0.001). History of recurrence, older age, and lower education had a significant correlation with general and disease specific QOL (P value < 0.001). CONCLUSION: The general QOL of patients with oral cancer was lower than that of the normal population in most domains. The postoperative QOL in our patients was significantly influenced by demographic and tumor-related factors. These factors should be considered by the treatment teams.

Application of Orthodontic Immediate Force on Dental Implants: Histomorphologic and Histomorphometric Assessment.

AIMS: Application of force to implants is helpful, especially in orthodontic-implant therapies. The aim of this study was a histomorphologic and histomorphometric evaluation of peri-implant bone after immediate orthodontic and orthopedic forces comparing them with a control group. MATERIALS AND METHODS: Eighteen dental titanium implants were inserted in the premolar region of three dogs. Implants were divided into three groups: (1) group with immediate orthodontic force of 300 NC, (2) group with immediate orthopedic force of 600 NC, and (3) control group. Implants were explanted with adequate amount of surrounding bone after 3 months and bone-implant contact (BIC), amount of lamellar bone (LB), amount of woven bone (WB), amount of inflammatory connective tissue, and the rate of the movement were investigated. ANOVA, t-test, paired t-test, and Pearson's test were used to analyze the data using SPSS software version 16 at a significant level of 0.05. RESULTS: Based on BIC, amount of lamellar and WB and the amount of inflammatory connective tissue, there was no significant difference between the three groups (300 centinewton (CN), 600-CN, and control group) (P > 0.05). In the 300-CN and 600-CN groups, the rate of movement was reported 0.41 and 0.94 with no significant differences (P = 0.38). CONCLUSION: 300-CN and 600-CN immediate static loads do not interfere with osseointegration phenomenon and it does not decrease the amount of BIC and LB. Implants can be moved by preserving osseointegration, and this movement is in direct relation with the amount of applied force.

Comparing the Efficacy of Three Different Nano-scale Bone Substitutes: In vivo Study.

BACKGROUND: Synthetic biocompatible bone substitutions have been used widely for bone tissue regeneration as they are safe and effective. The aim of this animal study is to compare the effectiveness of three different biocompatible bone substitutes, including nano-hydroxyapatite (nano-HA) nano-bioglass (nano-BG) and forstrite scaffolds. MATERIALS AND METHODS: In this interventional and experimental study, four healthy dogs were anesthetized, and the first to fourth premolars were extracted in each quadrant. After healing, the linear incision on the crestal ridge from molar to anterior segment prepared in each quadrant and 16 defects in each dog were prepared. Nano-HA, nano-BG, and forstrite scaffold was prepared according to the size of defects and placed in the 12 defects randomly, four defects remained as a control group. The dogs were sacrificed in four time intervals (15, 30, 45, and 60 days after) and the percentage of different types of regenerated bones (lamellar and woven) and connective tissue were recorded in histological process. The data were analyzed using Mann-Whitney test (α = 0.05). RESULTS: The difference in nano-HA and nano-BG with the control group was significant in three-time intervals regarding the amount of bone formation (P < 0.01). After 15 days, the nano-HA showed the highest amount of woven and lamellar bone regeneration (18.37 ± 1.06 and 30.44 ± 0.54). CONCLUSION: Nano-HA and nano-BG groups showed a significant amount of bone regeneration, especially after 30 days, but paying more surveys and observation to these materials as bone substitutes seem to be needed.

Pulp Response following Direct Pulp Capping with Dentin Adhesives and Mineral Trioxide Aggregate; An Animal Study.

INTRODUCTION: Pulp vitality and its continuous dentin prodution are essential for long-term success of direct pulp capping (DPC). The aim of present study was to evaluate the histopathological response of the canine pulp following DPC using either different dentin adhesive resins (DAR), calcium hydroxide (CH) or mineral trioxide aggregate (MTA). METHODS AND MATERIALS: DPC was done on 72 dog's teeth using 6 types of dental materials (n=12) (4 types of DAR, white MTA and CH). Therefore, six healthy dogs were anesthetized and 2 teeth from each dog were allocated to either type of mentioned DPC agents. The dental pulps were exposed mechanically by drilling in the center of class V cavities. The different types of capping materials included DARS (Clearfil S3 Bond, Optibond FL, Single Bond and Clearfil SE Bond), white MTA and CH. After 7, 21 and 63 days, two dogs were euthanized in each interval. Microscopic evaluations were done according to following criteria: intensity of inflammation, presence of necrosis and formation of hard tissue. The recorded data were analyzed by the Kruskal-Wallis, Friedman, Cochran's and Fisher's exact tests using SPSS software version 12 at significant level of 0.05. RESULTS: No significant differences were found regarding necrosis among DPC materials (P>0.05). However, MTA caused higher amount of hard tissue formation after 63 days in comparison with 21 days. CONCLUSION: MTA provided the highest degree of hard tissue formation after 63 days. However, further studies should be performed for administering a definitive material.