Effect of 980 nm photobiomodulation delivered by a handpiece with Gaussian vs. Flat-Top profiles on proliferation and differentiation of buccal fat pad stem cells.

The aim of this study was to compare the effectiveness of the Gaussian and Flat-Top profiles in proliferation and differentiation of mesenchymal stem cell of buccal fat pad. Based on the timing schedule and type of laser handpieces, the cells were assigned to a control group with no radiation, and two irradiation test groups (980 nm) with Flat-Top (F) (power of 1.1 W, beam area of 1 cm2 ) and standard Gaussian (G) (power of 0.7 W, beam area of 0.5 cm2 ) handpieces. Each test group was divided into three subgroups, receiving one time (60 J/cm2 ), two times (120 J/cm2 ), and three times (180 J/cm2 ) irradiation. 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and Annexin V tests were performed. The Alizarin Red staining and polymerase chain reaction tests were done both at the beginning and the end of the first and second weeks. The degree of mineralization and expression of osteogenic markers, RUNX2, OCN, and OPN were evaluated. Based on the MTT and Annexin V test results, both test groups outperformed the control group in degrees of cell proliferation during the first day of laser irradiation (p < 0.05). After one and two times irradiation, the expression of osteogenic markers in the test groups was significantly higher than the control group. PBM with Flat-Top and Gaussian handpieces can enhance ossification and cell differentiation regardless of the type of handpieces.

Dental service utilization and the COVID-19 pandemic, a micro-data analysis.

BACKGROUND: Global crises and disease pandemics, such as COVID-19, negatively affect dental care utilization by several factors, such as infection anxiety, disrupted supply chains, economic contraction, and household income reduction. Exploring the pattern of this effect can help policy makers to be prepared for future crises. The present study aimed to investigate the financial impact of COVID-19 disruptions on dental service utilization. METHODS: Data on the number of dental services offered in Dental School Clinics of Tehran University of Medical Sciences was collected over a period of two years, before and after the initial COVID-19 outbreak in Iran. School of Dentistry operates two clinics; one with competitive service fees and one with subsidies. Regression analyses were performed to determine the effect of the pandemic on the number of dental services divided by dental treatment groups and these clinics. The analyses were adjusted for seasonal patterns and the capacity of the clinics. RESULTS: There was a significant drop in dental services offered in both clinics across all dental groups in the post-COVID period (on average, 77 (39.44%) fewer services per day). The majority of the procedure loss happened in the Private clinic. Adjusting for seasonal patterns and the service capacity, regression results documented 54% and 12% service loss in Private and Subsidized clinics following the pandemic, respectively. Difference-in-difference analysis documented that the Subsidized clinic performed 40% more treatments than the Private clinic in the post-COVID period. CONCLUSIONS: Pandemic -reduction in dental care utilization could have long-term ramifications for the oral health of the population, and policymakers need to provide supportive packages to the affected segments of the economy to reverse this trend.

Application of Hyaluronic Acid for Treatment of Interdental Papillary Deficiency: A Systematic Review and Meta-Analysis.

Objectives: The focused question of this systematic review was "does hyaluronic acid (HA) injection in areas of interdental papillary deficiency reduce black triangles?" Materials and Methods: A systematic literature search was performed to find clinical studies on human patients with a minimum of 6-month follow-up, published in English from 2005 to May 2020. There were two outcome variables: black triangle area (BTA) change after treatment at different measurement time points compared with baseline, and patient reported outcome measures (PROMs), when available. Results: Of eight eligible articles (2 randomized clinical trials (RCTs) and 6 non-randomized, non-placebo controlled clinical studies), seven reported that HA injections had a positive impact on reduction of BTA and subsequent papillary augmentation. Six studies were included in meta-analysis and showed that the intervention led to a pooled reduction percentage of 57.7% in BTA after 6 months. Although there were clinical diversities between the studies, all the studies applied the same concentration of HA (approximately 2%), 2-3 mm apical to the papilla tip in several intervals. Some degrees of relapse were reported in some studies. Conclusion: Within the limits of this study, this systematic review and meta-analysis showed that HA injection can serve as an efficient minimally-invasive treatment for small interdental papillary deficiencies. It is essential to conduct further randomized clinical studies with prolonged follow-ups in order to support this conclusion.

Relationship of Maxillary Sinus Mucosal Thickening and Residual Alveolar Ridge Height: A CBCT Analysis.

Objectives: Maxillary sinus pathological conditions, like thickening of the Schneiderian membrane, can influence the outcomes of augmentation procedures and implant treatment. The present study aimed to evaluate the relationship between the residual ridge height and maxillary sinus membrane thickening. Materials and Methods: A total of 240 cone-beam computed tomography (CBCT) images of the maxillary sinus of 141 patients (62.1% males and 37.9% females, bilateral in 99 patients and unilateral in 42 patients) who were candidates for implant placement were evaluated. The CBCT scans were subsequently assessed for the following variables: residual ridge height, sinus membrane thickening at future implant(s) site(s), the ostium patency, and presence of periapical lesion adjacent to the edentulous area. Results: The total prevalence of sinus membrane thickening (66.2%) was sub-classified as follows: flat in 53.7%, polypoid in 12.1%, and complete opacification in 0.4%. The prevalence of sinus membrane thickening was higher in male participants. It was revealed that age had no significant relationship with presence of a periapical lesion or sinus membrane thickening (P>0.05). Membrane thickening was detected in all sinuses with obstructed ostium. Reduced residual ridge height was significantly associated with higher sinus membrane thickening at the second premolar and first molar sites (P<0.05). Conclusion: Maxillary sinus membrane thickening (mostly with flat appearance) is frequently observed on CBCT scans taken prior to augmentation and implant placement. This, in return, may trigger a reduction in ridge height.

COVID-19 Pandemic and Periodontal Practice: The Immunological, Clinical, and Economic Points of View.

The recent global health problem, COVID-19, has had far-reaching impacts on lifestyles. Although many effective WHO-approved vaccines have been produced that have reduced the spread and severity of the disease, it appears to persist in humans for a long time and possibly forever as everyday it turns out to have new mutations. COVID-19 involves the lungs and other organs primarily through cytokine storms, which have been implicated in many other inflammatory disorders, including periodontal diseases. COVID-19 is in a close association with dental and periodontal practice from two respects: first, repeated mandatory lockdowns have reduced patient referrals to dentists and limited the dental and periodontal procedures to emergency treatments, whereas it is important to recognize the oral manifestations of COVID-19 as well as the influence of oral and periodontal disease on the severity of COVID-19. Second, dentistry is one of the high-risk professions in terms of close contact with unmasked individuals, necessitating redefining the principles of infection control. The pressures of the economic recession on patients as well as dentists add to the difficulty of resuming elective dental services. Therefore, this study is divided into two parts corresponding to what mentioned above: the first part examines the clinical and immunological associations between COVID-19 and periodontal and oral diseases, and the second part delineates the measures needed to control the disease transmission in dental clinics as well as the economic impact of the pandemic era on dental services.

Effect of microthread design on the preservation of marginal bone around immediately placed implants: a 5-years prospective cohort study.

BACKGROUND: This study aimed to evaluate the effect of the microthread design at the implant neck on the preservation of marginal bone around immediately-placed implants in a 5-year follow up. METHODS: Thirty patients received 41 immediately placed implants which were randomly assigned to treatment groups with microthreaded implants (test group, n = 22) or threaded implants (control group, n = 19). Clinical and radiographic analyses were carried out after 1 and5 years. Plaque index, bleeding on probing, suppuration, probing depth and marginal bone loss were subject to evaluations. The results were analyzed with the T-test, Fisher's exact test and Mann-Whitney U test. RESULTS: No implants failed; thirty-five implants (in 27 patients); 21 microthreaded and 14 threaded implants; completed the 5 year follow up. The mean values of the marginal bone loss in microthreaded and threaded groups were 1.12 ± 0.95 mm and 0.87 ± 0.78 mm, respectively during an observation period of 70.9 ± 10.4 months; the differences in marginal bone loss and other pre-implant parameters were not significant between groups (P > 0.05). CONCLUSION: Both implant designs showed acceptable results in terms of the clinical parameters and marginal bone level. Within the limitation of this study, the results did not demonstrate any superiority of the microthread design compared to threaded one in marginal bone preservation around immediately placed implants over 5 years of loading.

Regenerative benefits of using growth factors in treatment of periodontal defects: A systematic review and meta-analysis with Trial Sequential Analysis on preclinical studies.

The ultimate goal in periodontal treatments is to achieve a functional and anatomical regeneration of the lost tissues. Numerous studies have in some way illustrated the beneficial effects of biologic modifiers in this process, yet they are subject to a rather large degree of diversity in their results. Thanks to the promising outcomes of bioengineering techniques in the field of periodontal regeneration, this systematic review aims to evaluate the effect of various biologic modifiers used in periodontal defects of animal models. Electronic databases (Medline, Scopus, Embase, Web of Science, and Google Scholar) were searched (March 2010-December 2020) for every study that used biomolecules for regeneration of periodontal osseous defects in animal models. Regenerated bone height or area, new cementum, new connective tissues, new regenerated periodontal ligament and the dimensions of epithelial attachment (either in mm/mm2 or percentage) were the investigated outcomes. The risk of bias of the included studies was assessed using the SYRCLE tool. In closing, there was a meta-analysis carried out on the outcomes of interest. Trial Sequential Analysis was also carried out to figure out the power of meta-analytic outcomes. From 1995 studies which were found in the initial search, 34 studies were included in this review, and 20 of them were selected for the meta-analysis. The eligible studies were categorized according to the morphology of the experimental periodontal defects as one-, two-, and three-wall intrabony defects; furcation defects, and recession-type defects. The most studied biomolecules were rhFGF-2, rhGDF-5, platelet-derived growth factor, bone morphogenetic protein-2, and enamel matrix derivative (EMD). Based on the meta-analysis findings, combined application of biomolecules with regenerative treatments could improve new bone and cementum formation near 1 mm when compared to the control groups in one, two and three-wall intrabony defect models (p < 0.001). In furcation grade II defect, the addition of biomolecules was observed to enhance bone area gain and cementum height regeneration up to almost 2 mm (p < 0.001). Trial Sequential Analysis results confirmed the significant effect in the aforementioned meta-analyses. In cases of the buccal recession model, the application of rhFGF-2 and rhGDF-5 decreased the dimension of epithelial attachments besides regenerative advantages on bone and cementum formation, but EMD deposition exerted no inhibitory effect on epithelial down-growth. Application of biologic modifiers especially FGF-2 and GDF-5, could positively improve the regeneration of periodontal tissues, particularly cementum and bone in animal models. Trial Sequential Analysis confirmed the results but the power of the evidences was high just in some subgroup meta-analyses, like bone and cementum regeneration in furcation grade II model and cementum regeneration in one-wall intrabony defects. The outcomes of this study can potentially endow clinicians with guidelines for the appropriate application of growth factors in periodontal regenerative therapies.

Semelil as Adjunctive Therapy in Chronic Periodontitis: A Preliminary Randomized Controlled Clinical Study.

Host modulation therapy is recently employed to improve periodontal treatments outcome. This randomized controlled clinical trial aimed to evaluate the effects of Semelil (ANGIPARS) as an adjunct to non-surgical treatment in patients with chronic periodontitis. Forty-four healthy subjects with moderate to severe chronic periodontitis were enrolled in the study. After completion of phase I periodontal therapy, including oral hygiene instruction, scaling, and root planing, the patients were randomly divided into two groups to receive capsules of Semelil (test) or placebo (control), consuming two capsules a day for three months. Clinical parameters (probing depth [PD], clinical attachment level [CAL], modified sulcular bleeding index [MSBI], modified gingival index [MGI], and plaque index [PI]) and biochemical parameters (interleukin-1ß [IL-1ß], 8-hydroxy-2-deoxyguanosine [8-OHdG]), and lipid peroxidation [LPO]) were measured at baseline and after completion of treatment. Twenty-five patients completed the study: 15 in the test group and 10 in the control group. All clinical and biochemical parameters were significantly improved from baseline to the final measurements in both groups (p < 0.001). The changes were more pronounced in the test group in comparison to the control group. However, the differences between the groups were significant only for MGI, MSBI, PD, and CAL (p < 0.05). Semelil may reveal promising results as an adjunctive treatment for chronic periodontitis.

The effects of topical erythropoietin on non-surgical treatment of periodontitis: a preliminary study.

BACKGROUND: The purpose of periodontal treatments is to reduce inflammation, restore gingival health and clinical attachment level gain by controlling microbial plaque formation and other etiological factors. One of the drugs that has been tested in many areas and shown good anti-inflammatory properties is erythropoietin (EPO). We evaluated the effect of this drug on the improvement of periodontitis after the phase I treatment. METHODS: This study was conducted on 30 patients with stage III periodontitis who had at least two bilateral teeth with CAL of ≥ 5 mm and PPD ≥ 6 mm at ≥ 2 non-adjacent teeth and bleeding on probing. After oral hygiene instruction and scaling and root planning (SRP), EPO gel containing a solution of 4000 units was applied deeply in the test group and placebo gel was deeply administered in the control pockets (5 times, every other day). The clinical parameters of the plaque index (PI), gingival index (GI), clinical attachment level (CAL), probing depth (PD) and bleeding index (BI) were measured at baseline and after three months of follow up. The P-value was set at 0.05. RESULTS: All clinical variables improved after treatment in both groups. The BI and GI scores (which reflects the degree of gingival inflammation) showed statistically more reduction in test group. The CAL decreased from 5.1 ± 4.1 to 3.40 ± 2.71 mm; and 5.67 ± 4.32 to 4.33 ± 3.19 mm in test and control group, respectively (P < 0.00). After the treatment, there was a significant greater reduction in CAL and also PD values in test group (P < 0.01). CONCLUSION: Local application of EPO gel in adjunct to SRP can improve clinical inflammation and CAL gain in periodontitis. TRIAL REGISTRATION: This study was registered at 2017-11-06 in IRCT. All procedures performed in this study were approved with ID number of IR.TUMS.DENTISTRY.REC.1396.3139 in Tehran University of medical science.

Marginal bone loss around bone-level and tissue-level implants: A systematic review and meta-analysis.

PURPOSE: To review the scientific evidence regarding the marginal bone loss around the tissue-level and bone-level implants. METHODS: MEDLINE-PubMed and EMBASE databases were searched for the relevant English articles (up to February 2019) assessing the marginal bone loss (MBL) as the primary outcome. To be selected, studies were supposed to directly mention "tissue-level" and "bone-level" implants or implants with and without a smooth neck. Relevant data were extracted and meta-analysis was performed to evaluate the effect of implant neck design. RESULTS: A total of 19 studies (10 clinical, and 9 RCT studies) were included for qualitative analysis. There was a vast heterogeneity between studies in terms of implant designs and study protocol. Out of 19 articles included, 11 studies reached to a statistically significant difference in MBL between the groups; however, the differences were not found to be clinically relevant. Bone-level implants with platform-switched abutments in most of the cases showed better marginal bone stability compared to tissue-level implants or bone-level implants with matching abutments. Seven RCTs with 12 months follow-up data were selected for meta-analysis (I2=93%; heterogeneous), and the results showed less MBL around bone-level implants compared to tissue-level group (WMD=-0.21mm; 95% CI -0.42, 0.00; P=0.06). CONCLUSION: The available data regarding comparison of MBL around bone-level and tissue-level implants are heterogeneous. Bone-level implants with platform switching may better preserve crestal bone.

Vitamin K and Bone Metabolism: A Review of the Latest Evidence in Preclinical Studies.

Bone is a metabolically active tissue that renews itself throughout one's life. Cytokines along with several hormonal, nutritional, and growth factors are involved in tightly regulated bone remodeling. Accordingly, vitamin K as a multifunctional vitamin has been recently deemed appreciable as a topic of research as it plays a pivotal role in maintenance of the bone strength, and it has been proved to have a positive impact on the bone metabolism. Vitamin K exerts its anabolic effect on the bone turnover in different ways such as promoting osteoblast differentiation, upregulating transcription of specific genes in osteoblasts, and activating the bone-associated vitamin k dependent proteins which play critical roles in extracellular bone matrix mineralization. There is also credible evidence to support the effects of vitamin k2 on differentiation of other mesenchymal stem cells into osteoblast. The main objective of the present paper is to comprehensively outline the preclinical studies on the properties of vitamin K and its effects on the bone metabolism. The evidence could shed light on further clinical studies to improve osteogenesis in bone graft surgeries.

Interleukin-17 and interleukin-23 levels in gingival crevicular fluid of patients with chronic and aggressive periodontitis.

INTRODUCTION: Interleukin-17 is a pro-inflammatory cytokine with a wide range of protective and destructive effects in periodontitis. The role of IL-23 is stabilisation and expansion of Th-17. The aim of this study was to assess whether patients with aggressive and chronic periodontitis exhibit different gingival crevicular fluid (GCF) concentrations of IL-17 and IL-23 compared with clinically healthy subjects. MATERIAL AND METHODS: GCF samples were obtained from 32 patients: 10 with chronic periodontitis (CP), 12 with aggressive periodontitis (AgP), and 10 healthy controls (HC). IL-23 and IL-17 concentrations were measured using enzyme-linked immunosorbent assay (ELISA). Comparison of study groups was performed with ANOVA and Tukey HSD tests. Spearman's correlation coefficient was used to assess correlations between the variables. RESULTS: IL-17 concentration was significantly higher in the healthy group compared to the AgP and CP groups (p < 0.001), but there were no significant differences between the CP and AgP groups. IL-23 levels in the healthy group were significantly higher than that in the AgP group (p < 0.001). Cytokine concentrations did not correlate significantly with probing depths and clinical attachment levels. CONCLUSIONS: Gingival crevicular fluid concentrations of IL-17 and IL-23 were significantly higher in the healthy group compared to periodontitis groups.

Effect of Flapless Immediate Implantation and Filling the Buccal Gap with Xenograft Material on the Buccal Bone Level: A Randomized Clinical Trial.

OBJECTIVES: Following tooth extraction, soft and hard tissue alterations occur; Different factors can affect this process. The objective of this study was to determine the effect of gap filling on buccal alveolar crestal bone level after immediate implant placement after 4- to 6-month observation period. MATERIALS AND METHODS: This randomized clinical trial was performed on 20 patients (mean age of 38.8 years) requiring tooth extraction in a total of 27 areas in the anterior maxilla. The treatment strategy was as follows: atraumatic flapless tooth extraction, implant placement, insertion of a graft (test group) or no material (control group) between the implant and the socket wall, connection healing abutment placement and suturing the area. Clinical and cone beam computed tomographic examinations were performed before implant placement (baseline), 24 hours after surgery and 4-6 months (T2) after implant placement, to assess the buccal plate height (BH) and implant complications. RESULTS: After 4 months of healing, a reduction in different bone measurements was noticed in the two groups. No statistically significant differences were assessed in bone height measurements between the test and control groups at different time points. The study demonstrated that immediate implantation resulted in 1.30 and 1.66 mm reduction in buccal bone plate in the test and control groups, respectively. CONCLUSIONS: The study demonstrated that immediate implantation in the extraction socket together with xenograft failed to prevent bone resorption.

Prevalence of peri-implantitis in patients not participating in well-designed supportive periodontal treatments: a cross-sectional study.

OBJECTIVES: This retrospective cross-sectional study aimed to evaluate the prevalence of biologic complications of implants in patients treated by fixed implant supported prosthesis without regular maintenance program. MATERIALS AND METHODS: One hundred thirty-four patients with 478 implants, installed during a 10-year period (2001-2010), were recruited for clinical and radiographic follow-up examinations. The periodontal and implant health status were assessed to determine the prevalence of peri-implant diseases. RESULTS: The mean ± SD loading time for implants was 4.43 ± 2.25 years. Fifty-five percentage of the implants were tissue-level implants. Peri-implantitis was diagnosed in 20% of patients and 8.8% of implants. Subject-based and implant-based prevalence of mucositis amounted to 48.5% and 40%, respectively. Mean crestal bone loss in tissue-level and bone-level implants were 0.28 ± 0.53 mm and 1.37 ± 1.5 mm, respectively. Smoking and lack of keratinized mucosa was associated with peri-implantitis at an odds ratio of OR = 2.57 and 3.89, respectively. CONCLUSIONS: After a 5-year period of loading without any regular maintenance program, one out of five patients would experience peri-implantitis. Tissue-level implants had lower values of peri-implantitis prevalence and crestal bone loss.

Effect of Periodontal Treatment on the Crevicular Level of High-mobility Group Box 1 and Soluble Triggering Receptor Expressed on Myeloid Cells 1 in Patients with Chronic Periodontitis.

The present study aimed to compare the levels of high-mobility group box 1(HMGB1) and soluble triggering receptor expressed on myeloid cells (sTREM1) in the gingival crevicular fluid (GCF). This cross-sectional cohort trial investigated two groups of 22 eligible chronic periodontitis and 22 periodontally healthy individuals (student volunteers) both before and after the periodontal treatment.  GCF was collected from the deepest pockets with clinical attachment loss≥3 mm. Both groups received oral hygiene instructions, and scaling and root planning were performed in the test group. Enzyme-linked immunosorbent assay kit (ELISA) was used to measure the levels of HMGB1 and sTREM1 in GCF samples collected before and 1 month after non-surgical periodontal treatment. The results showed that HMGB1 levels were significantly higher in the chronic periodontitis patients than those of the healthy individuals before treatment (p<0.02) and decreased significantly after periodontal treatment, which reduced gingival inflammation. Furthermore, the levels of sTREM1 marker were significantly higher in periodontitis patients before (p<0.001) and 1 month after treatment than in healthy individuals (p<0.003) although its crevicular levels decreased after periodontal therapy in periodontitis group. The higher levels of sTREM1 and HMGB1 cytokines in GCF of periodontitis patients and the significant decrease after the introduction of the periodontal treatment underlines the importance of HMGB1 and sTREM1 in pathogenesis of periodontitis.

Laser-Assisted Osteotomy for Implant Site Preparation: A Literature Review.

PURPOSE: The aim of this study was to review the scientific evidence about the laser osteotomy in implant bed preparation. METHODS: An electronic search was performed on relevant English articles up to April 2016 in the PubMed, Scopus, and Google Scholar databases. RESULTS: Twenty-two articles (1 clinical, 13 animal, and 8 ex vivo studies) were included. Implant sites prepared by erbium family lasers and drill showed comparable results regarding the percentage of bone-to-implant contact, values of biomechanical tests, and healing process. Selection of proper laser wavelength and parameters was of paramount importance to minimize the risk of thermal bone damage. Lack of depth control and long time needed for implant site osteotomy with laser were the most challenging concerns for its clinical applicability. Computer-guided laser osteotomy showed promise for future use of laser osteotomy in clinical settings. CONCLUSION: Evidence from animal studies shows promising results regarding laser osteotomy in implant site preparation. However, because of the lack of clinical studies, it is not possible to make a conclusive result whether there is superiority of laser osteotomy in clinical practice.

Effect of TNF-α Blockade in Gingival Crevicular Fluid on Periodontal Condition of Patients with Rheumatoid Arthritis.

BACKGROUND: Periodontitis and rheumatoid arthritis (RA) share a number of clinical and pathologic features, one of which is the presence of the tumor necrosis factor alpha (TNF-α)-induced bone resorption that is involved in the pathogenesis of both. OBJECTIVES: To investigate the effect of TNF-α blockade on periodontal conditions in patients with active RA. METHOD: The periodontal statuses of 36 patients (26 females, 10 males) diagnosed with active RA were evaluated both before and after anti-TNF-α therapy. Gingival index, bleeding on probing (BOP), probing pocket depth (PPD), oral hygiene index (OHI), and levels of TNF-α in gingival crevicular fluid (GCF) were measured at the baseline and 6 weeks after the treatment. Wilcoxon signed ranked test was used for statistical analyses. RESULTS: Based on OHI (p=0.860), the level of plaque control did not change during the study period, but there was a significant reduction in gingival inflammation based on the mean BOP (p=0.049) and GI (p=0.036) before and after 6 weeks of anti-TNF-α therapy. The mean PPD index did not significantly differ at the baseline and 6 weeks after treatment (p=0.126). CONCLUSION: Anti-TNF-α therapy might have a desirable effect on periodontal conditions and might reduce TNF-α level in GCF of patients with RA.

Accuracy of Linear Measurements Using Cone Beam Computed Tomography in Comparison with Clinical Measurements.

OBJECTIVES: This study sought to evaluate the accuracy and errors of linear measurements of mesiodistal dimensions of Kennedy Class III edentulous space using cone beam computed tomography (CBCT) in comparison with clinical measurements. MATERIALS AND METHODS: Nineteen Kennedy Class III dental arches were evaluated. An impression was made of each dental arch and poured with dental stone. The distance was measured on dental cast using a digital Vernier caliper with an accuracy of 0.1mm and on CBCT scans. Finally, the linear mesiodistal measurements were compared and the accuracy of CBCT technique was evaluated by calculating absolute value of errors, intra-class correlation coefficient and simple linear regression model. RESULTS: In comparison with the cast method, estimation of size on CBCT scans had an error of -8.46% (underestimation) to 5.21% (overestimation). In 26.5% of the cases, an accepted error of ±1% was found. The absolute value of errors was found to be in the range of 0.21-8.46mm with an average value of 2.86 ±2.30mm. CONCLUSIONS: Although the measurements revealed statistically significant differences, this does not indicate a lower accuracy for the CBCT technique. In fact, CBCT can provide some information as a paraclinical tool and the clinician can combine these data with clinical data and achieve greater accuracy. Undoubtedly, calibration of data collected by clinical and paraclinical techniques and the clinician's expertise in use of CBCT software programs can increase the accuracy of implant placement.

Effects of Immediate and Delayed Loading on the Outcomes of All-on-4 Treatment: A Prospective Study.

OBJECTIVES: The purpose of this study was to compare the outcomes of immediate and delayed rehabilitation of edentulous jaws by means of two straight and two tilted implants after one year of function. MATERIALS AND METHODS: Thirty consecutive patients (16 males, 14 females) were enrolled in this study. Two anterior straight and two posterior tilted implants were placed in each patient. According to the implant insertion torque and the need for bone grafting, implants were loaded immediately (at 72 hours) or delayed (after four months) using a fixed metal resin prosthesis. RESULTS: One axial implant failed in the delayed group after one year of loading, resulting in cumulative implant survival rate of 99.3%. The mean marginal bone loss was 0.84mm. No significant difference was found between axial and tilted implants in the two groups (P>0.05). CONCLUSIONS: Based on the results, immediate or delayed fabrication of final prosthesis on two tilted and two axial implants did not result in significant differences in survival rates or marginal bone loss.

Relationship between maternal periodontal disease and low birth weight babies.

BACKGROUND: Periodontal infections, which serve as a reservoir of inflammatory mediators, may pose a threat to the fetal-placental unit and cause adverse pregnancy outcomes. OBJECTIVE: The aim of this study was assessing the periodontal status of women during puerperium and determining the possible relationship between their periodontal disease and low birth weight delivery. MATERIALS AND METHODS: This was a case-control study. The sample included 88 ex-pregnant women were seen at maternity hospitals of Yazd, Iran. Half of the mothers had low birth babies (LBW) (birth weight below 2500g- case group) and the others had normal weight babies (>2500g- control group). The mothers' data were obtained from medical files, interview and periodontal clinical examination carried out up to 3 days after delivery. Bleeding on probing, presence of supra-gingival calculus and CPITN (Community Periodontal Index for Treatment Needs) were used for periodontal assessment Results: Among the known risk factors of LBW babies, history of previous LBW infant among case mothers reached statistical significance (p=0.0081, Student t-test). Mothers of LBW infants had less healthy areas of gingiva (p=0.042), and more deep pockets (p=0.0006, Mann-Whitney test). CONCLUSION: The maternal periodontal disease can be a potential independent risk factor for LBW.