Marginal bone loss around crestal or subcrestal dental implants: prospective clinical study.

Objectives: The stability of crestal bone has been reported as a major factor in the success of dental implants. Implants can be placed in an equicrestal (crestal) or subcrestal position. The aim of this study was to evaluate the effect of implant depth placement on marginal bone loss. Materials and Methods: The study was created in a split-mouth design. Immediately after implant surgery, digital parallel radiographs were prepared and levels of bone were measured where marginal bone loss and bone level changes occurred. These measurements were repeated at 3-month and 6-month follow-up periods. Results: In this interventional study, 49 implants were evaluated in 18 patients. Primary bone height was not significant between the intervention and control groups in both mesial and distal aspects at 3 months and 6 months from the baseline. The mean marginal bone loss on the mesial side was 1.03 mm in the subcrestal group and 0.83 mm in the crestal group. In addition, mean marginal bone loss on the distal side was 0.88 mm and 0.81 mm in the subcrestal and crestal groups, respectively. Marginal bone loss was not significantly different between sexes, the maxilla or mandible, and in the anterior or posterior regions as well as between different lengths and diameters of implants. Conclusion: Based on the results of this study, there was no significant difference in terms of marginal bone loss between crestal and subcrestal implants.

Histological Evaluation of Bone Regeneration Using Hydroxyapatite Based Bone Substitute Derived from Antler: An Animal Study.

OBJECTIVE: 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. METHODS AND MATERIALS: 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. RESULTS: 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. CONCLUSION: 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.

Surgical Treatment of a Huge Pleomorphic Adenoma in the Hard Palate of a Young Female Adult: A Case Report.

Pleomorphic adenoma is the most common salivary gland tumor. This tumor mostly involves the parotid gland; however, if it occurs in the minor salivary glands, the palate would be the most common site. This lesion is more prevalent in patients with 40 to 60 years of age. Regarding the literature, the incidence of giant pleomorphic adenoma of the palate in young patients is considered a rare finding. Hereby, we present a rare case of pleomorphic adenoma of the palate, with an astonishing size, found in a 27-year-old patient. Furthermore, the surgical treatment of this lesion is described. This case was effectively treated with surgical curettage and tumor resection, emphasizing the significance of early detection in order to minimize complications. Surgical treatment, was beneficial to help the patient resume to normal life. Additionally, the clinical, radiological, and histopathological aspects and potential surgical treatments are discussed.

The evaluation of implant stability measured by resonance frequency analysis in different bone types.

OBJECTIVES: Bone density seems to be an important factor affecting implant stability. The relationship between bone density and primary and secondary stability remains under debate. The aim of this study was to compare primary and secondary stability measured by resonance frequency analysis (RFA) between different bone types and to compare implant stability at different time points during 3 months of follow-up. MATERIALS AND METHODS: Our study included 65 implants (BioHorizons Implant Systems) with 3.8 or 4.6 mm diameter and 9 or 10.5 mm length in 59 patients. Bone quality was assessed by Lekholm-Zarb classification. After implant insertion, stability was measured by an Osstell device using RFA at three follow-up visits (immediately, 1 month, and 3 months after implant insertion). ANOVA test was used to compare primary and secondary stability between different bone types and between the three time points for each density type. RESULTS: There were 9 patients in type I, 18 patients in type II, 20 patients in type III, and 12 patients in type IV. Three implants failed, 1 in type I and 2 in type IV. Stability values decreased in the first month but increased during the following two months in all bone types. Statistical analysis showed no significant difference between RFA values of different bone types at each follow-up or between stability values of each bone type at different time points. CONCLUSION: According to our results, implant stability was not affected by bone density. It is difficult to reach a certain conclusion about the effect of bone density on implant stability as stability is affected by numerous factors.

Comparison of the effect of hemihydrate calcium sulfate granules and Cerabone on dental socket preservation: An animal experiment.

Background. Early bone loss due to tooth extraction can be significantly reduced by socket preservation. The aim of this study was to compare the in vivo effects of hemihydrate calcium sulfate granules (an alloplastic material) and Cerabone (a bovine-derived xenograft) on socket preservation in dogs. Methods. Six male Mongrel dogs were randomly divided into 2 groups (n=3) for sacrificing and histological evaluation 4 and 8 weeks after a surgery. The second and third premolars on both sides of the lower jaw were extracted surgically. The sockets on one side were filled with Cerabone, and with calcium sulfate on the opposite side. In the slides, the ratio of the area of newly formed bone to the area of the entire cavity, and the ratio of the area of fibrous connective tissue to the area of the entire cavity were measured. The presence of inflammation was also examined. Wilcoxon signed-rank test, Sign test and McNemar test were used for statistical analyses (ɑ=0.05). Results. The means of new bone proportion were 11% and 8% for Cerabone and calcium sulfate, respectively (P=0.58). The means of connective tissue proportion were 29% and 33% for Cerabone and calcium sulfate, respectively (P=0.72). No inflammatory cells were observed in the Cerabone group, although 50% of the samples in the calcium sulfate group showed inflammation (P=0.50). Conclusion. The effects of calcium sulfate and Cerabone on socket preservation in dogs on bone formation, fibrous connective tissue and inflammation levels were not significantly different at 4- and 8-week postoperative intervals.

Evaluation of crestal bone resorption around cylindrical and conical implants following 6 months of loading: A randomized clinical trial.

OBJECTIVE: The purpose of this clinical study was to evaluate the effect of implant body form (cylindrical and conical implants) on crestal bone levels during 6 months' follow-up after loading. MATERIALS AND METHODS: A total of 32 SPI implants (19 conical implants/13 cylindrical implants) were randomly placed in 12 male patients using a submerged approach. None of the patients had compromising medical conditions or parafunctional habits. Periapical radiographs using the parallel technique were taken after clinical loading and 6 months later. Clinical indices including pocket depth and bleeding on probing (BOP) were recorded on 6-month follow-up. Data were analyzed by independent samples t-test and Chi-square test with a significance level of 0.05. RESULTS: Six months after loading, crestal bone loss was 0.84 (±0.29) mm around the cylindrical implants and 0.73 (±0.62) mm around the conical types, which was not significantly different (P = 0.54). Pocket depth around the cylindrical and conical implants was 2.61 (±0.45) mm and 2.36 (±0.44) mm, respectively (P = 0.13). BOP was observed among 53.8% and 47.4% of the cylindrical implants and conical (P = 0.13). Bone loss and pocket depth in the maxilla and mandible had no significant difference (P = 0.46 and P = 0.09, respectively). CONCLUSION: In this study, although bone loss and clinical parameters were slightly higher in the cylindrical implants, there was no significant difference between the conical- and cylindrical-shaped implants.

Comparison of Three types of Tooth Brushes on Plaque and Gingival Indices: A Randomized Clinical Trial.

OBJECTIVE: To compare clinical results of three types of manual tooth brushes on plaque removal efficacy and gingivitis. METHOD: This study is a single blind randomized trial with crossover design which involved 30 periodontaly healthy individuals. Professional plaque removal and oral hygiene instruction were performed for all the participants in the first step of our study followed by asking them to avoid brushing for 2 days. Thereafter plaque and gingivitis scores were measured using plaque and gingival indices (PI and GI). Then subjects were instructed to use Pulsar tooth brush for a two-week period and then, GI and PI indices were assessed again. After passing one-week period for wash out, subjects didn't brush for 2 days and indices were recorded again. The same procedure was done for CrossAction, and Butler 411 tooth brushes respectively and at the end of the study these variables were analyzed using SPSS software ver.16. Repeated measurement ANOVA test was used to compare the scores between different brushes. RESULT: Finding of this study reveals that using all three types of tooth brushes resulted in significant plaque and gingivitis reduction compared to baseline levels. Pulsar tooth brush was significantly more effective in diminishing PI and GI than Butler tooth brush (p=0.044 and 0.031 respectively). CONCLUSION: According to our findings all 3 types of tooth brushes are effective in reduction of plaque and gingivitis and this reduction is significantly greater for Pulsar tooth brush compared to Butler and CrossAction tooth brushes.