Comparison of healing time and the histopathology of bone formation following tooth extraction using freeze-dried bone allograft:A randomized controlled clinical trial.

Background. A decrease in the width and height of the alveolar ridge is inevitable following tooth extraction. This study aimed to histologically evaluate the amount of newly formed bone after using a freeze-dried bone allograft (FDBA) at two different intervals in the tooth socket grafting. Methods. Forty patients were selected, who required a single-rooted tooth extraction and were candidates for implant placement, with no indication for an immediate implant. Extraction sockets were preserved using a cortical FDBA allograft in two regeneration interval groups: 3 months (group A) and 4 months (group B). At the time of implant placement, a bone sample was collected from each grafted socket. Histomorphometric analyses were performed to determine the percentage of newly formed bone and the residual graft material. Changes in histological indices, i.e., inflammation rate, percentage of ossification, and the amount of remaining biomaterial, were evaluated. Results. There were no significant differences in the amount of newly formed bone and residual graft material between the two groups. In general, the average of new bone formation and remaining graft particles in groups A and B was: %33.89 and %12.59 vs. %39.83 and %14.07, respectively. Conclusion. Bone parameters in group A were better compared to group B. However, due to the lack of significant differences in the results, it is suggested that implant placement in grafted sockets with mineralized allografts be expedited.

Reopening of dental clinics during SARS-CoV-2 pandemic: an evidence-based review of literature for clinical interventions.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes serious acute respiratory diseases including pneumonia and bronchitis with approximately 2.3% fatality occurrence. MAIN BODY: This study argues the main concepts that need to be considered for the gradual reopening of dental offices include treatment planning approaches, fundamental elements needed to prevent transmission of SARS-CoV-2 virus in dental healthcare settings, personal protection equipment (PPE) for dental health care providers, environmental measures, adjunctive measures, and rapid point of care tests in dental offices. CONCLUSION: This article seeks to provide an overview of existing scientific evidence to suggest a guideline for reopening dental offices.

A new classification of the sagittal root positioning of the mandibular anterior teeth in relation to their anterior buccal bone using cone-beam computed tomography (CBCT).

Background: This study aimed to develop a classification for the sagittal root positioning (SRP) of mandibular anterior teeth in terms of their anterior buccal bone for use before placing immediate implants. Methods: A retrospective review of CBCT images was conducted on 150 patients (75 males and 75 females; mean age: 47.5 years) who met the inclusion criteria. The root position of the tooth samples was classified as buccal, middle, or lingual types according to their respective sagittal position and subtypes a, b, c, or d, according to the morphology of their osseous housing. Results: The frequencies of the root positions of each classified group of the sample teeth were as follows: 14% buccal type, 77% middle type, and 8% lingual type; 18.0% subtype a, 4.33% subtype b, 75.55% subtype c, and 2.11% subtype d. As a complementary procedure for data collection, the sagittal position of the apex was classified into Class I (buccally angulated apex: 4.6%), Class II (apex with no angulation: 78.2%), Class III (lingually angulated apex: 0.7%) and Class IV (exposed root: 16.3%). In addition, the results of the examination of the buccal undercut showed that in 1.6%, 32.0%, and 66.3% of the sample teeth, the undercut was located coronally, medially, and apically, respectively. Conclusion: Considering these results, the newly proposed SRP classification system can be used to study the mandibular anterior buccal bone morphology as a diagnostic tool for immediate implant treatment.

Effect of two commercial acellular dermal scaffolds on biological behavior of human gingival fibroblasts.

Background: Periodontal regeneration is an essential goal of periodontal therapy. Acellular dermal matrix (ADM) has been recommended as an alternative to autogenous grafts. However, since it is devoid of cells and vasculature, there are concerns regarding the biological behavior of cells on ADM. This study aimed to assess the effects of two commonly used ADMs on biological behavior, i.e., attachment and proliferation, of human gingival fibroblasts (HGFs). Methods: This in vitro, experimental study was conducted on explanted and cultured HGFs. ADM types 1 and 2 (n=26; measuring 10×15 mm) were rinsed with saline solution, adapted to the bottom of 52 wells, exposed to HGFs with a cell density of 16,000 cells/mL, and incubated at 37°C for 12, 24, and 84 hours and seven days. Cell attachment was assessed 12 hours after incubation using 4>,6-diamidino-2-phenylindole (DAPI) and methyl-thiazol-diphenyl-tetrazolium (MTT) assay under a fluorescence microscope. Cell viability was assessed at 24 and 84 hours and one week using the MTT assay. Cells were then platinum-coated, and their morphology was evaluated under a scanning electron microscope (SEM). Data were analyzed using ANOVA. Results: HGFs were evaluated in 60 samples in three groups (n=20). Cell attachment was the same in the three groups, as shown by the MTT assay and DAPI test (P=0.6). Cell viability at one week was 3.73±0.02, 2.88±0.29, and 2.13±0.24 in the control, ADM 1, and ADM 2 groups, respectively. The difference was statistically significant (P=0.01). Conclusion: Both scaffolds were the same in terms of attachment of HGFs. However, ADM 1 was superior to ADM2 in terms of cell viability and morphology at one week. It was concluded that the quality of acellular dermal scaffolds could significantly influence cellular behaviors and tissue maturation.

Vestibular incisional subperiosteal tunnel access versus coronally advanced flap with connective tissue graft for root coverage of Miller's class I and II gingival recession: A randomized clinical trial.

Background: This study aimed to compare the clinical efficacy of vestibular incisional subperiosteal tunnel access (VISTA) with subepithelial connective tissue graft versus a coronally advanced flap (CAF) with subepithelial connective tissue graft for the treatment of gingival recession defects. Materials and Methods: This randomized clinical trial was performed on 24 recession defects that were bilaterally Miller's class I or II in the maxillary canine and premolar area. One quadrant in each patient was selected randomly to receive VISTA (test group) or CAF (control group) with connective tissue graft. Clinical parameters measured at baseline and at 3- and 6- month postoperative intervals included recession width (RW), recession depth (RD), keratinized tissue width (KTW), clinical attachment level (CAL) and probing depth (PD). Results: Healing was uneventful in both the test and control groups. At the 6-month follow-up, there was a significant decrease in RD, RW and CAL and an increase in KTW in both the test and control groups. The PD remained unchanged. At 3 and 6 months, no statistically significant differences were found between VISTA and CAF for root coverage and clinical attachment gain. Mean root coverage (MRC) was 70.69% and 67.22% in the test and control group, respectively. VISTA demonstrated higher frequency of complete root coverage (CRC) compared to CAF: 50% vs. 33% (P<0.05). The mean KTW was 2.4±0.7 mm at the test and 2.7±0.8 mm at the control sites (P>0.05). Conclusion: VISTA, as a minimally invasive approach, can enhance root coverage, KTW and clinical attachment gain; therefore, it can be used as a substitute for CAF with connective tissue graft as a gold standard for root coverage.

Inter- and intra-examiner agreement of three classification systems of gingival recession.

Background: Several classifications have been proposed for gingival recession defects. Correct diagnosis of the type of gingival recession is necessary for proper treatment planning and assessment of the prognosis. Considering the existing uncertainty regarding the reliability of different classification systems available for gingival recession and their shortcomings, this study sought to assess the reproducibility and reliability of accuracy of three available classifications (Cairo, Mahajan and Miller's classification systems) for gingival recession. Methods: This descriptive study was conducted on 32 patients presenting to the Department of Periodontics, who were selected using convenience sampling. The screening process entailed two sessions and those with a minimum of one site of gingival recession disclosing the cementoenamel junction (CEJ) of the tooth with no adjacent tooth loss at the site of recession were enrolled. Each patient was separately evaluated by three calibrated examiners twice with a minimum of one-week interval. Grading of the gingival recession defects was determined using the Cairo, Mahajan and Miller's classification systems for gingival recession. The gradings of each examiner were separately recorded by a blinded examiner. A total of 120 single recession defects were examined and data were analyzed using intra-class correlation coefficient (ICC) and Spearman's test. Level of agreement was evaluated according to Landis and Koch. Results: The results showed that the reliability of all the three methods was almost perfect (P<0.05), and no significant difference was noted in reliability of the Cairo, Mahajan and Miller's classifications for gingival recession (P=0.7). Conclusion: Based on the results of the study, the highest intra- and inter-observer agreement in the use of the three classifications belonged to the Cairo classification; however, all the three classifications showed high reliability.

Efficacy of Connective Tissue with and without Periosteum in Regeneration of Intrabony Defects.

Background and aims. Connective tissue grafts with and without periosteum is used in regenerative treatments of bone and has demonstrated successful outcomes in previous investigations. The aim of present study was to evaluate the effectiveness of connective tissue graft with and without periosteum in regeneration of intrabony defects. Materials and methods. In this single-blind randomized split-mouth clinical trial, 15 pairs of intrabony defects in 15 patients with moderate to advanced periodontitis were treated by periosteal connective tissue graft + ABBM (test group) or non-periosteal connective tissue graft + ABBM (control group). Probing pocket depth, clinical attachment level, free gingival margin position, bone crestal position, crest defect depth and defect depth to stent were measured at baseline and after six months by surgical re-entry. Data was analyzed by Student's t-test and paired t-tests (α=0.05). Results. Changes in clinical parameters after 6 months in the test and control groups were as follows: mean of PPD reduction: 3.1±0.6 (P<0.0001); 2.5±1.0 mm (P<0.0001), CAL gain: 2.3±0.9 (P<0.0001); 2.2±1.0 mm (P<0.0001), bone fill: 2.2±0.7 mm (P<0.0001); 2.2±0.7 mm (P<0.0001), respectively. No significant differences in the position of free gingival margin were observed during 6 months compared to baseline in both groups. Conclusion. Combinations of periosteal connective tissue graft + ABBM and non-periosteal connective tissue graft + ABBM were similarly effective in treating intrabony defects without any favor for any group. Connective tissue and perio-steum can be equally effective in regeneration of intrabony defects.

Comparison of nickel and chromium ions released from stainless steel and NiTi wires after immersion in Oral B®, Orthokin® and artificial saliva.

AIM: Oral environment of the mouth is a suitable place for biodegradation of alloys used in orthodontic wires. The toxicity of these alloys namely nickel and chromium has concerned the researchers about the release of these ions from orthodontic wires and brackets. The aim of this study was to measure the levels of nickel and chromium ions released from 0.018" stainless steel (SS) and NiTi wires after immersion in three solutions. MATERIALS AND METHODS: One hundred and forty-four round NiTi and 144 round SS archwires with the diameters of 0.018" were immersed in Oral B®, Orthokin® and artificial saliva. The amounts of nickel and chromium ions released were measured after 1, 6, 24 hours and 7 days. RESULTS: Two way repeated ANOVA showed that the amount of chromium and nickel significantly increased in all solutions during all time intervals (p < 0.002). CONCLUSION: Chromium and nickel ions were released more in NiTi wire in all solutions compared with SS wire. The lowest increase rate was also seen in artificial saliva. CLINICAL SIGNIFICANCE: There is general consensus in literature that even very little amounts of nickel and chromium are dangerous for human body specially when absorbed orally; therefore, knowing the precise amount of these ions released from different wires when immersed in different mouthwashes is of high priority.