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Guided bone regeneration (GBR) is considered as a prerequisite in some cases of implant dentistry. For this purpose, bone materials are commonly used. Calcium compounds and Ca-P based materials like hydroxyapatite (HA, Ca10 (PO4)6(OH)2), due to their similarity with the human bone, can be used as graft materials for bone regeneration. This study aimed to evaluate biocompatibility of antler xenograft and compare the osteoconduction effects of antler xenograft with Cerabone in regeneration of calvarium bony defects of rabbits.Five defects with a diameter of 6 mm and a depth of 3 mm were prepared in the calvarium of four rabbits. Thereafter, two defects were randomly grafted with antler xenograft, two defects were filled with Cerabone, and one defect remained as the untreated group. Histological evaluations, including measuring percentage of new regenerated bone and the amounts of osteoblast, osteoclast, and osteocyte cells, were also performed. To do statistical analyses, paired t-test, chi-square, and Fisher tests were applied.The percentage of new bone formation was significantly higher in antler xenograft (73.33%) and in Cerabone (48.91%) compared to the untreated group (18.91%). The amounts of osteocytes and osteoblasts were obtained as 3.52 ± 0.17 and 2.41 ± 0.24 in the Antler xenograft and as 2.57 ± 0.29 and 2.31 ± 0.32 in the Cerabone group, respectively. Bone marrow formation were significantly higher in antler xenograft (6.66 ± 5.34) and Cerabone (1.99 ± 3.17) compared to the untreated group.According to this pilot study, results of using antler xenograft as an osteoconductive materials in regeneration of rabbit calvarial defects are comparable with Cerabone. Although more clinical studies are needed.

This retrospective study was aimed to compare the clinical and radiographic outcomes of implants with the same body design but different collar surface (laser-microtextured vs. not laser-microtextured) after functional loading. Forty-three patients (29 females, 14 males) with 139 implants (60 laser-microtextured and 79 without laser microtexturing) were included in this study. Patients were consecutively included, and the data were collected during their implant maintenance visit. Clinical and radiographic parameters including probing depth (PD), bleeding on probing (BoP), and marginal bone loss (MBL) were recorded. In addition, the implant success index (ISI) score was determined. Statistical analysis was performed using the Mann–Whitney U test, the Kruskal–Wallis rank test, or the Pearson χ2 test, along with binary logistic regression (p

Background Improvement in implant design has made implant dentistry a challenging treatment modality worldwide. Objectives This study aimed to investigate the efficacy of a xenogeneic collagen matrix in managing 3-4-millimeter gaps in flapless immediate implant placement. Material and methods Twenty-two patients received 39 immediate implants via the flapless approach. Patients with intact bony walls, buccal bone thickness ≥2 mm and a jumping distance of 3-4 mm were included in this study. The gap between the implant and the socket walls was filled with a xenogeneic collagen matrix (Collacone®). The final clinical and radiographic evaluations were performed at least 24 months following functional loading. Results There was no early or late failure, and the implants showed a 100% survival rate. The mean mesial (0.28 ±0.39 mm) and distal (0.28 ±0.39 mm) marginal bone loss (MBL) at the site of incisors was not significantly different from the values at the site of premolars and molars (0.30 ±0.42 mm and 0.34 ±0.48 mm, respectively). The evaluation of the implant success index (ISI) score revealed no difference between the mandible and the maxilla (p = 0.700), or incisors compared with premolars and molars (p = 0.420). The only significant difference was in terms of distal MBL, which was higher in the maxilla (0.39 ±0.49 mm) than in the mandible (0.12 ±0.23 mm) (p = 0.040). Conclusions Within the limitations of this study, it seems that the application of a xenogeneic collagen matrix to manage 3-4-millimeter gaps in carefully selected cases may bring promising outcomes.

Consenting to a dental implant treatment plan may be a challenging decision for many patients, and they may prefer to consult their family and friends before making the final decision on this matter. The purpose of this preliminary report was to assess the role of family and friends, as the consultees, in consenting to a dental implant treatment plan by patients.A total of 106 patients with dental implants were questioned about whether they made the final decision regarding their dental implant treatment by themselves or they consulted their family and friends prior to finalizing their decision.The majority of men (52.1%) reported making this decision by themselves and based on their own personal opinion, while most women (48.2%) reported making the decision after consulting their children.Within the limitations of this preliminary report, it appears that women are more willing to consult their children and friends on this matter compared with men. Also, men mostly consult their wives in making such a decision while women pay more attention to the opinion of their children in this respect.

Successful bone regeneration often requires induction by signaling molecules. Enamel matrix derivative (EMD) is said to enhance initial phases of healing. N-acetyl cysteine (NAC) is a molecule assumed to enhance osteogenesis and induce osteoblastic differentiation. This study sought to compare effects of EMD and NAC on proliferation, mineralization, and enzymatic activity of dental pulp mesenchymal stem cells (DPSCs). DPSCs were cultured on mineralized bone allograft (MBA) powder. After 24 hours, EMD in concentrations of 10, 50, and 100 μg/mL and NAC in 5 mM concentration were added. Methyl thiazolyl tetrazolium (MTT) assay was used for cell proliferation assessment at 1, 2, and 3 days. Osteoblastic differentiation of DPSCs was evaluated at 30 days, by alizarin red staining and assessment of alkaline phosphatase (ALP) activity. Both EMD and NAC caused time-dependent reduction of cell proliferation compared with the negative control. Maximum proliferation of DPSCs was observed in the 10 μg/mL EMD group at all time points, whereas NAC caused higher ALP activity and mineralization of DPSCs compared with EMD. In vitro application of NAC, as a signaling molecule, may effectively enhance bone regeneration by the induction of mineralization and enzymatic activity, despite the resultant reduction in cell proliferation rate.

Introduction - This study aimed to compare the amount and pattern of stress and strain distributed around periodontally compromised splinted teeth and the two-implant abutments supported six-unit fixed partial denture (FPD) using finite element analysis (FEA). Methods and Materials - Six mandibular anterior teeth of a dental model were scanned and the scans were transferred to 3D CAD design and finite element software. Jaw bone was also designed and the teeth were splinted by fiber-reinforced composite (FRC) band. In another model, two implants were placed at the site of canine teeth and a six-unit FPD was designed over them. Models were transferred to finite element software and after meshing and fixing, they were subjected to 100- and 200-N loads under 0 and 30° angles. Results - Apical areas and crestal bone showed the highest accumulation of stress and strain in periodontally compromised splinted teeth. Crestal bone and bone between crestal microthread and the first thread of implant body had the highest accumulation of stress and strain in the implant supported six-unit FPD. Conclusion - The results showed significantly higher shear stress, von Mises stress and von Mises strain in peri-implant bone compared with bone around periodontally compromised teeth. Increase in applied load magnified this difference. Also, a greater difference was noted in stress and strain in bone around teeth and implants when oblique load was applied.

This in vitro study aims to assess inward bacterial microleakage at the implant-healing abutment (IHA) interface in two different implant designs, namely platform switching (PS) and platform matching (PM). Five samples were collected from each of the PS and PM implant systems. In the first phase, healing abutments were tightened onto the implants by 10 Ncm torque. Next, IHA assemblies were immersed in an Escherichia coli (E. coli) suspension for 24 hours and 7 and 14 days. The healing abutments were then unscrewed, and samples were collected from the internal part of the implants and streak-cultured on culture media. After 1 day of incubation, the number of grown colonies was counted. In the second phase, the aforementioned steps were repeated for the assemblies that were torqued by 20 Ncm. Data were analyzed by the Kruskal-Wallis and Mann-Whitney tests (α = 0.05). The mean colony count was found to increase over time in the PM group torqued by 10 and 20 Ncm; however, this increase was only significant for 10 Ncm torque (P = 0.02). In the PS group, the colony count did not follow a certain pattern over time, neither in the 10 Ncm nor in the 20 Ncm torque. The mean colony count in the PS group was lower than that in the PM group at all time points in both torques. This difference was not significant at day 1, irrespective of torque value, but it was significant at 7 and 14 days, in both 10 and 20 Ncm torques (P < 0.05). Thus microleakage is lower in PS than PM design. The selection of a PM or PS design is a more important factor than the applied torque (10 or 20 Ncm) for reduction of bacterial microleakage in Tube-in-Tube implant systems with screw-retained connections.

Objective. The aim of this study was to determine the average and maximum height of the papilla around maxillary anterior implants in respect of neighboring structures and location of implants. Materials and Methods. 92 dental implants from 63 patients were investigated in this study. Those implants were placed in the anterior maxillary region and had been loaded for a minimum of one year. After receiving written consent, clinical data including the height of interproximal papillae adjacent to the tooth/implant/pontic were obtained through clinical observation. The independent t-test or ANOVA, the regression modeling, and generalized estimating equation (GEE) models were used for statistical analysis ( p < 0.05 ). Results. Papilla height was calculated as 2.8 mm (1–5.5 mm) for implant-tooth sites, 2.6 mm (1–4 mm) in implants beside pontics, and 2.5 mm (1–3.5 mm) for implants adjacent to implants. Despite the lack of a significant difference in the mean papilla height in the studied groups, the maximum values of papilla heights were significantly different. Conclusions. In this study, no significant differences were found in papilla height mean values in relation to neighboring structures or location of implants in the anterior maxilla. However, the maximum values of papilla heights were observed around implants next to natural teeth.

Objectives - Aphthous stomatitis is one of the most common ulcerative lesions in the oral cavity. The aim of this study was to report the characteristics of patients with aphthous stomatitis after dental implantation. Patients and Method - The study included 14 patients who were diagnosed with aphthous stomatitis. The subjects were analyzed with the respect to age, sex, patient's general health status, type, number, location, and duration of the ulcers and the number of dental implants. Results - Of the 14 cases, 64.3% were female and 35.7% were male. The mean age of patients was 57.7. In terms of general health status, 64.3% of patients did not have a remarkable disease; however, 14.3%, 14.3%, and 7.1% of cases had diabetes, hypothyroidism, and cardiac disease, respectively. The majority of the lesions have been presented as minor type (85.7%) and the mean number of the ulcers was 2.5. Labial mucosa has been affected more frequently (71.4%), followed by tongue and floor of the mouth. The most lesions (42.8%) were occurred one day after dental implant surgery. The mean number of dental implants was 3.1. Conclusion - Presence of apthous ulcers should be considered by dentists as a potential postoperative complication of dental implantation.

Background Bone volume plays a pivotal role in the success of dental implant treatment. Autogenous bone grafts should be harvested from reliable sites in the maxillofacial region. This study sought to assess the quantity and quality of bone in the mandibular symphysis for autogenous bone graft harvesting using cone-beam computed tomography (CBCT). Methods This cross-sectional study evaluated the CBCT scans of 78 adults presenting to three oral and maxillofacial radiology centers. The vertical (VD) and horizontal (HD) alveolar bone dimensions, cortical thickness (CT), and cancellous to cortical bone ratio (C/C) were measured in the interforaminal region of the mandible at the sites of central incisor to first premolar teeth. The interforaminal distance (ID) and the anterior loop length were also measured. Nonparametric statistical tests were used to analyze the data with respect to sex, age, and tooth position. Results The median VD, HD, and CT of the symphysis were 20.21 (3.26), 4.13 (0.37), and 2.25 (0.23) mm, respectively. The median C/C was 1.51 (0.11). The median ID was 52.24 (8.24) mm, and the median anterior loop length was 1.82 (1.06) mm. Significant differences were observed in all parameters among different teeth. Most of the measured parameters were greater in males compared with females. There were significant differences in ID, VD, and CT between different age groups. Conclusions The quantity and quality of the available bone in the mandibular symphysis for bone graft harvesting vary by gender, age, and harvesting site, necessitating careful preoperative evaluation.

Objective Contemporary implantology is moving toward less invasive approaches. To date, several techniques have been proposed for maxillary sinus lift surgery. In this article, we introduce a new technique for maxillary sinus floor elevation that is less invasive than the osteotome technique. Methods and materials In the vertical expander screw (VES) technique, which uses a combination of drilling and bone-expander screws; a primary implant hole is created. Bone expander screws are used in lateral and vertical dimensions to elevate the sinus membrane. Results The results at the two-year follow-up revealed bone formation around the implant body in the bony sinus cavity for three patients. Accordingly, 100% survival and success rates were reported for implants placed with VES technique. Conclusion The maxillary sinus floor can be elevated to the desired height with a VES technique with minimal invasion. The VES technique can be used as an alternative to elevate the sinus floor with less invasion than the osteotome technique.

Introduction - Scaffolds and cells are two important components in bone tissue engineering. There is a gap of information about stem cell activity next to bone substitutes. Thus, the aim of this in vitro study was to compare the proliferation and differentiation of bone marrow stem cells (BMSCs) and dental pulp stem cells (DPSCs) in presence of freeze-dried bone allograft (FDBA). Method and Materials - DPSCs and BMSCs were cultured and placed on mineralized bone allograft. Cell proliferation was analyzed by the methyl thiazolyl tetrazolium (MTT) assay after 24, 48, and 72 h. To compare the enzymatic activity and mineralization of cells, the alkaline phosphate (ALP) test and alizarin red staining were performed at 30 days. Data were analyzed by ANOVA. Results - The rate of proliferation of DPSCs was higher at 48 and 72 h. ALP activity was significantly higher in DPSCSs (P < 0.05), while alizarin red staining did not show any significant difference between the groups in formation of calcified nodules. DPSCs showed higher cell proliferation and osteoblastic differentiation than BMSCs. Conclusion - Considering the easier and less invasive isolation of DPSCs, a combination of DPSCs and allograft can be a good choice for bone regeneration, especially in the dentoalveolar area.

Leukocyte platelet-rich fibrin (L-PRF) has the potential to accelerate wound healing. Here, we assess clinical and radiographic outcomes of socket preservation using L-PRF. For this single-blind, randomized, split-mouth clinical trial, we selected 22 patients (15 males and seven females), who required extraction of single-rooted teeth. Subjects were randomly assigned to two groups. We used L-PRF in the extraction socket on one side and no material on the contralateral side. We obtained cone-beam computed tomographic images and diagnostic casts from tooth extraction sockets before surgery and 3 mo after the procedure. Changes in buccolingual diameter and height of bone at 3 mo after tooth extraction (compared to baseline) were determined and digitized data statistically analyzed using Statistical Package for the Social Sciences software, ver. 25.0 (IBM, Armonk, NY) via the paired t-test. In tooth sockets with/without L-PRF application 3 mo after extraction, bone buccolingual diameter significantly decreased at socket center to 0, 1, and 3 mm from the ridge crest, compared to baseline. A significant reduction occurred in sockets with/without L-PRF application in buccal and lingual bone height at the bony socket midbuccal portion of and mesial and distal septa (p < 0.0001). However, the Mann-Whitney U test showed changes to be significantly greater in controls than the case group (p < 0.0001). Taking into account study limitations, application of L-PRF in tooth extraction sockets significantly decreased reductions in bone height and buccolingual diameter compared to control sockets.

This study sought to histologically and histomorphometrically assess and compare application of xenograft bone substitute and synthetic nonceramic hydroxyapatite for tooth-socket preservation in dogs. This split-mouth clinical trial was conducted in five hybrid dogs, using four tooth sockets in each dog, with a total of 20 sockets for evaluation. Group 1 received xenografts, and group 2 received synthetic nonceramic hydroxyapatite in the sockets. In group 3 (positive controls), sockets remained empty. All sockets were covered with collagen resorbable membrane, and the flap was stitched using nonresorbable sutures. In group 4 (negative control), sockets were without membrane, left empty, and sutured. After 12 wk, 8-mm-high bone core biopsies were harvested from inside the sockets, using a trephine bur with an internal diameter of 2 mm. We assessed the tissue in terms of percentage of newly formed viable bone, percentage of remaining particles, degree of inflammation, and type of connective tissue. Data were statistically analyzed. The percentage of newly formed viable bone was 34.98% in group 1 and 41.30% in group 2, and this difference was not statistically significant (p = 0.710). The percentage of remaining particles was 15.95% in group 1 and 14.14% in group 2; this difference was also not statistically significant (p = 0.902). Both synthetic nonceramic hydroxyapatite and xenograft bone substitute showed similar efficacy, histologically and histomorphometrically, when used with resorbable collagen membrane for tooth-socket preservation in dogs.

Background The finite element method (FEM) has been used to analyze stress and strain distributions around 3 suggested dental implants with newly-designed thread parameters and the optimal shape of the implant was introduced considering the response surface optimization method sensitivity analysis. Experimental tests seemed necessary to confirm the results of the FEM. Objectives The aim of this study was to use experimental tests to prove the results of a finite element analysis of 3 dental implants with different thread designs under axial loads. Photoelastic stress analysis was chosen due to the similarity of analysis with FEM. Material and methods Two-dimensional models of 3 dental implants were built of grade 4 titanium to be tested in the polariscope. Model 1: A tapered implant with V-shaped threads; Model 2: A tapered implant with micro-threads in the upper area and V-shaped threads in the rest of the body; Model 3: A tapered implant with reverse buttress threads in all areas. Axial loading of 100 N was applied to the top of the implants and stress patterns and the maximum stress were evaluated for each implant. Results The minimum Huber-Mises-Hencky stresses of cortical bone were recorded in model 2, a tapered implant with micro-threads in the upper area and V-shaped threads in the rest of the body. The value for 100 N loading was 15.25 MPa, which was in agreement with the FEM. Conclusions Considering the stress patterns and values obtained from experimental tests of photoelasticity, the tapered implant with micro-threads in the upper area and V-shaped threads in the rest of the body has the most uniform and desirable stress distribution in the surrounding cortical bone and is preferred to be used in future applications.

This study sought to assess the relationship between facial gingival and bone dimensions in maxillary anterior teeth region using cone beam computed tomography (CBCT).This study assessed 621 maxillary anterior teeth in 144 patients. In the sagittal plane, facial bone thickness (BT) and gingival thickness (GT) were measured at the crestal level and at 2, 4 and 6mm apical to the cementoenamel junction (CEJ). The dentogingival complex (DGC) dimensions and the distance from the CEJ to bone crest were also measured on CBCT scans. To determine the gingival biotype, GT at 2mm apical to the gingival margin was measured and GT1.5mm was categorized as thin while GT ≥1.5mm was categorized as thick. The data were analyzed using SPSS version 21 via repeated measures ANOVA and the Cochrane's Q, chi-square and independent samples t-tests.The BT around the maxillary central and lateral incisors and canine teeth at 4 and 6mm apical to the CEJ was significantly different in thick and thin gingival biotypes (P0.05). The mean GT at 2 and 4mm apical to the CEJ was significantly different around central and lateral incisors (P0.05). Thickness of crestal bone was significantly different between the two gingival biotypes around central and lateral incisors (P0.05).The two gingival biotypes had significantly different mean BT; different biotypes and their relationship to BT varied around anterior maxillary teeth.

COVID-19 has imposed tremendous burden on the healthcare systems and healthcare professionals worldwide. As periodontitis and peri-implantitis are chronic diseases, regular recall visits play a critical role in management of these conditions; however, the current situation may stop patients from attending their regular maintenance. Therefore, it may be necessary to reconsider and revise the treatment protocols.

The aim of this study was to assess stress and strain patterns in cortical and cancellous bones surrounding newly designed dental implants with different thread patterns. Static loading of dental implants has been well studied, but studies on dynamic loading and fatigue analysis of dental implants are scarce. This study analyzed the static, dynamic, and fatigue behaviors of dental implants using finite element analysis (FEA). Two models of dental implants were analyzed in this study. Model A was a tapered implant with V-shaped threads and model B was a tapered implant with microthreads in the uppermost region and V-shaped threads in the rest of the body. Two types of loading conditions were simulated in an FEA model and stress and strain patterns in the surrounding bone were analyzed. Dynamic loading increased the level of stress by 5-10% compared with static loading. Both implants showed acceptable results under static and dynamic loadings, but the second implant with microthreads caused lower stress and strain in cortical and cancellous bones. Dynamic and fatigue analyses can provide a more realistic understanding of the function of dental implants. Replacing the uppermost threads with microthreads can lead to more desirable stress patterns in bone, as well as a higher safety factor and longevity.

Short implants can be used as alternatives to standard implants to prevent invasive surgical procedures. However, due to concerns about complications caused by less bone-implant contact area, researchers have focused on biomechanical properties of short implants and methods to promote them. Splinting has been suggested to decrease the limitation of short implants. This study compared the pattern of stress and strain distribution in bone supporting splinted standard and short implants positioned at crestal and subcrestal levels. An edentulous posterior mandible was made using computer-aided design. Five models of different combinations of splinted short (4 × 6 mm) and standard (4 × 10 mm) implants placed at the level of crestal bone or subcrestally mesial and distal to the edentulous region with a pontic between them were designed using the CATIA software program. ANSYS software was used for finite element analysis (FEA). In each model, 100 and 300 N loads at zero (parallel to the long axis of implants) and 30° angles were applied to implants. Maximum stress and strain for each of the five models, including equivalent stress, shear stress, and strain in peri-implant cortical and cancellous bone, were calculated and stress distribution pattern in different models were recorded. The highest stress was caused by the 300 N load applied at a 30° angle, followed by the 300 N load applied axially and the 100 N load applied at 30°. This order changed in model 1, where the highest stress was noted under the 300 N load at 30°, followed by the 100 N load at 30°. Maximum stress in peri-implant bone occurred under oblique (30°) load. Maximum stress was noted when two splinted short implants were placed subcrestally. In addition, stress in bone around crestal-level splinted short implants was lower than that around standard implants. Combination of short and standard implants had no biomechanical advantage. Application of load parallel to the long axis can significantly decrease stress in peri-implant bone. Although the combination of short and standard implants has no biomechanical advantage, crestal-level placement of splinted short implants is a suitable treatment plan.

Periodontitis is an infectious disease of the tooth-supporting tissues. Specific periodontal pathogens trigger inflammatory responses and result in progressive bone loss, which eventually leads to exfoliation of teeth. Periimplantitis is the destructive inflammatory process affecting the soft and hard tissues surrounding dental implants. The periodontal pathogens found around failing implants are very similar to those associated with various forms of periodontal diseases. Genetic susceptibility has been known to be an important risk factor for periodontitis and periimplantitis and there have been numerous studies evaluating this in different populations. Many gene polymorphisms may influence individual susceptibility to periodontitis and peri-implantitis. We conducted a review of the literature for gene polymorphisms associated with periodontitis and peri-implantitis susceptibility in the Iranian population. A comprehensive search of the literature on human studies in English, published from January 2004 to February 2015 in PubMed database and Google scholar was performed using the key words "periodontitis," "peri-implantitis," "gene polymorphisms," and "Iranian population." Sixty-six studies were identified; 33 articles were excluded based on review of titles and abstracts. Thirty articles were eligible and had the full text evaluated. Further studies are needed to get more inclusive perception of the influence of gene polymorphisms in periodontitis and peri-implantitis.

Objective RANK/OPG/RANKL pathway plays a significant role in osteoclastogenesis, osteoclast activation, and regulation of bone resorption. The aim of this study was to investigate the association of RANKL gene polymorphisms (rs9533156 and rs2277438) with chronic periodontitis and peri-implantitis in an Iranian population. Design 77 patients with chronic periodontitis, 40 patients with peri-implantitis and 89 periodontally healthy patients were enrolled in this study. 5cc of blood was obtained from the cephalic vein of subjects arms and transferred into tubes containing EDTA. Genomic DNA was extracted using Miller's Salting Out technique. The DNA was transferred into 96 division plates, transported to Kbioscience Institute in United Kingdom and analyzed using the Kbioscience Competitive Allele Specific PCR (KASP) technique. Differences in the frequencies of genotypes and alleles in the disease and control groups were analyzed using Chi-square and Fisher's exact statistical tests. Results Comparison of frequency of alleles in SNP rs9533156 of RANKL gene between the chronic periodontitis group with the control and peri-implantitis groups revealed statistically significant differences ( P = 0.024 and P = 0.027, respectively). Comparison of genotype expression of SNP rs9533156 on RANKL gene between the peri-implantitis group with chronic periodontitis and control groups revealed statistically significant differences ( P = 0.001); the prevalence of CT genotype was significantly higher amongst the chronic periodontitis group. Regarding SNP rs2277438 of RANKL gene, comparison of prevalence of genotypes and frequency of alleles did not reveal any significant differences ( P = 0.641/ P = 0.537, respectively). Conclusions The results of this study indicate that CT genotype of rs9533156 RANKL gene polymorphism was significantly associated with peri-implantitis, and may be considered as a genetic determinant for peri-implantitis.

Immediate implantation related to socket and vital anatomy of the maxillary sinus area requires careful consideration. One major complication that may occur during immediate replacement of posterior teeth is maxillary sinus membrane perforation. To date, no specific technique has been proposed to manage this problem so that implant insertion remains possible during the same surgery. In this paper, we introduce a method to manage this type of perforation and while performing simultaneous implantation. We used sinus-socket osteotomy (SSO), a modified osteotomy technique for socket preparation that blocks sinus perforation with autogenous bone. A 12-month follow-up showed that this technique was clinically successful and reduced the overall treatment time. However, this advanced method requires a skillful surgeon.

AIM: MicroRNAs (MiRs) are small noncoding RNAs that are involved in protein translation, osteoclastogenesis, and immunoregulation. Peri-implantitis and chronic periodontitis are multifactorial diseases. They are the consequence of complex interactions among host response, genetics, and environment. In the present study, we aimed to investigate the possible association between MiR146a/MiR499 gene polymorphisms and periodontitis/peri-implantitis as a first report in oral implantology. METHODS: From 197 individuals referred to Periodontology Department of Shahid Beheshti Dental School, three groups were enrolled in the assessment: 75 patients in the chronic periodontitis (CP) group, 38 patients in the peri-implantitis (PI) group, and 84 healthy subjects. DNA was extracted from fresh blood samples from the arm veins of participants and transferred to KBiosience Institute (Hoddesdon, United Kingdom) for genotyping. Chi-squared and Kruskal-Wallis tests were performed using SPSS software v.19 for statistical analyses. P-value < 0.05 was considered significant. RESULTS: The genotype frequencies in MiR 146a and MiR 499 were significantly different among the three groups. CONCLUSIONS: MiR146a (rs2910146) and MiR499 (rs3746444) gene polymorphisms may be genetic determinants for increased risk of chronic periodontitis and peri-implantitis in Iranians. More studies with larger sample sizes in different populations are necessary for determining the effect of these SNPs.

The aim of this study was to use intra-oral radiographs to evaluate changes in marginal bone levels around three different implant designs after 1 year.Three implant designs; two with a straight and one with a conical design, were placed adjacent to each other in the partially edentulous areas of 25 patients. The patients received 46 implants with a straight design (All fit SSO and SPI-element) and 29 implants with a conical design (SPI-contact). Two-way repeated analysis of variance (ANOVA) was used to evaluate the marginal bone changes in each group at 12 months follow-up (p0.05).None of the implants had failed by the end of this study. After 12 months, significant differences were noted in the amount of alveolar bone loss recorded between the All fit SSO and SPI implants (p0.05). Mean crestal bone loss was 0.88 ± 0.43 mm for the All fit, 0.61 ± 0.34 mm for the SPI contact and 0.54 ± 0.27 mm for the SPI element implants.The results of this study demonstrate that straight (cylindrical) implants with shorter high polish surface displayed less bone resorption.

AIMS The present study aimed at evaluating the acceptability of the Implant Success Index (ISI) in comparison with the conventional classification system. MATERIALS AND METHODS A comparative questionnaire was designed to evaluate 10 criteria that were reported to be important for acceptance of a new classification system. We asked 20 experts who had at least 5 years of clinical experience in implant dentistry to complete a questionnaire based on a visual analog scale. Data were analyzed by a blinded statistician using a Wilcoxon non-parametric rank test. RESULTS Measuring all 10 criteria, the acceptability level of ISI was significantly higher than that of the Misch classification (70.90 and 54.90, respectively; P < 0.05). The most significant differences were found in the system's ability to detect early lesions, its lack of overestimation, its quantitative base, and its comprehensiveness. The simplicity and compatibility of the two understudy classification systems were not significantly different. CONCLUSIONS ISI seems to be a proper scoring system with a high level of acceptability for determining the success rate of dental implants and for selection of procedures used for improving the status of peri-implant tissue.

Cigarette smoking and tobacco consumption are serious hazards threatening the health of human beings. Several strategies have been proposed for smoking cessation in patients presenting to medical centers to seek treatment. Some believe that the dental profession plays a key role in quit smoking programs due to its extensive and long-term relationship with patients. Use of known strategies to create motivation for quitting smoking among patients has yielded relatively optimal results. However, it seems that patients' attitudes toward smoking can be changed if we enhance their knowledge about the hazards of tobacco consumption and its adverse effects on dental and oral health and especially the health of dental implants' surrounding structures. This study reports smoking cessation in two patients requiring dental implant treatment. Twenty-eight months after loading of implants, treatment success was confirmed by use of clinical and radiographic indices. No sign of peri-implant disease was detected and the patients were eagerly following the smoking cessation program. It seems that contemporary dental treatments, especially dental implant therapy, can provide a good opportunity to create the motivation required for lifestyle changes in patients.

Objectives: The aim of this study was to investigate the effects of implant design on the apex area and on stress and stress patterns within surrounding bone. Methods: Three commercially available implants with the same diameter (3.5 mm), same length (10-11 mm), and same complement abutment were selected for modeling as follows: (1) flat apical design with light tapering degree, (2) dome-shaped apical design with light tapering, and (3) flat apical design with intense tapering in one-third of the apical area. According to human cone-beam computed tomography (CBCT), the bone was modeled using a cortical thickness of 2 mm and cancellous bone. Forces of 100 N and 300 N in the vertical and 15° angle directions were applied to the entire abutment surface, and the equivalent stress and strain were calculated using finite element analysis (FEA) methods. Results: In all models, stress was concentrated on the cortical bone around the implant neck; in non-axial loads, stress was concentrated on the buccal side. The maximum strain recorded was a microstrain of 7200 μm μm-1 around the apex of sample C, which also showed the highest level of stress detected in cancellous bone (4.4 MPa). We observed the pathologic overload in the apical area of sample B (with a dome-shaped apex); however, the strain value was less than that of sample C. Conclusion: FEA revealed that great sudden changes in diameter along the fixture increases stress and strain in peri-implant bone. Therefore, uniform tapering should be considered as a standard feature for most clinical situations, and a flat apical design, which creates a better stress and strain distribution in surrounding bone than dome-shaped bone, should also be used. © 2014 by Begell House, Inc.

Aim To explore the relationship between primary implant stability and cortical bone thickness. Materials and methods Twenty-three implants were inserted into fresh sheep bone. The cortical width of implant recipient sites was determined using cone-beam computed tomography (CBCT). The maximum insertion torque value of each implant was recorded. Implant stability was measured using an Osstell system. Spearman's correlation coefficient was used to evaluate the correlations among variables. Results The cortical width and Hounsfield unit mean values were 3.3 ± 1.0 (mm) and 1468.5 ± 272.3, respectively. The correlation between cortical bone thickness and Osstell value was not statistically significant (p > 0.01). Conclusion The cortical bone thickness evaluated using CBCT had no correlation with the primary stability of dental implants.

UNLABELLED: This study sought to determine TANK (rs1921310, rs3820998) gene polymorphism in patients suffering from chronic periodontitis and peri-implantitis among an Iranian population. MATERIALS AND METHODS: In this cross-sectional study, 77 chronic periodontitis and 40 peri-implantitis patients, along with 89 periodontally healthy subjects, were evaluated. A 5 cc venous blood sample was obtained from subjects. DNA was extracted using Miller's salting-out method and polymorphisms were determined by the use of KBioscience's Competitive Allele-Specific PCR (CASP) genotyping system. Data were analyzed using SPSS version 11.5 software. Differences in allele and genotype frequencies among patients and controls were evaluated with Kruskal-Wallis test. P

AIM In the present study, we sought to assess the correlation of IKKi gene polymorphisms (rs1539243 and rs12728136) with chronic periodontitis and peri-implantitis in an Iranian population for the first time in dentistry. MATERIALS AND METHODS This cross-sectional study was conducted on 75 patients with chronic periodontitis, 38 patients with peri-implantitis, and 84 periodontally healthy subjects. Blood samples were taken from all subjects (5 cc venous) and transferred into Falcon tubes containing EDTA. Extracted DNA samples were evaluated with a spectrophotometer (75 ng), transferred into a 96-well plate, and sent to KBioscience Institute in the United Kingdom for analysis. Assessment of IKKi gene polymorphisms was performed at the KBioscience Institute. Data were analyzed using SPSS v19 software. Differences in genotype frequencies and allele among patients and controls were evaluated using the chi-squared test (P

Aim: The purpose of this study was to investigate the cytotoxicity of nanohybrid mineral trioxide aggregate (MTA) in comparison with calcium-enriched mixture (CEM) cement and MTA-Angelus, using human gingival fibroblasts (HGFs). Materials and Methods: Nine disc-shaped specimens of each material (in 2 set stat: A, set for 24 h; B, set for 30 min; and C, fresh stat) were prepared. HGFs were exposed to tested materials’ extracts or control media. Cytotoxicity testing was performed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide assay in two time intervals. Statistical Analysis: Results were evaluated by one-way ANOVA and t-test. Statistical significance was set at P < 0.05. Results: CEM cement demonstrated favorable cell viability values when completely set (24 h set MTA = 24 h set CEM) at both time intervals. Interestingly, 24 h after incubation, CEM in Groups B and C demonstrated higher cell viability values than MTA (P < 0.05). However, after 72 h of incubation, these groups of CEM and MTA showed equal cell viability. All samples of nanohybrid MTA had slight cytotoxic effects after 24 h of incubation, and moderate cytotoxic effects after 72 h of incubation. Conclusion: Set CEM and set MTA-Angelus exerted similar, favorable effects on cell viability. However, within the limitations of this in vitro study, the results suggest that nanohybrid MTA could not be recommended as a material of choice for cervical root resorption.

AIMS The purpose of this study was to evaluate the regenerative response of parietal bone defects in rats to bioactive ceramic and TGF-beta 1. MATERIALS AND METHODS Sixty mature adult rats with initial weights of 300 g to 324 g were used. The diameter of each defect was 3 mm. The animals were divided into four study groups consisting of 15 rats per group. Groups 1 and 3 (control groups) received 30 μg bioceramic per surgical defect site. Groups 2 and 4 (experimental groups) received 30 μg bioceramic combined with 10 μL of reconstituted TGF-beta 1 (200 ng). Animals of Groups 1 and 3 were euthanized at 18 days; Group 2 and 4 animals were terminated at 49 days after surgery. Each of the outcomes was analyzed via two-way analysis of variance model (ANOVA). RESULTS Histologic reactions to the implants were similar with no significant difference between bioceramic and bioceramic + TGF-beta 1 specimens. In the 18-day specimens, the percentage of ceramic was marginally higher than the 49-day specimens. No significant difference was noted in the percentage of bone in 18-day and 49-day specimens. CONCLUSIONS Based on the findings of this study, it was concluded that TGF-beta 1 promoted no significant increase in new bone when compared to bioactive ceramic alone.