Keyvan Sohrabi

University of Toronto, Toronto, Ontario, Canada

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Publications (14)10.25 Total impact

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    ABSTRACT: Introduction: While there are a growing number of studies on the effects of medications on orthodontic tooth movement (OTM), only few studies have investigated the role of corticosteroids, despite their widespread use. The aim of the current study was to evaluate the effects of triamcinolone acetonide injection on OTM in a rabbit model. Study design: Sixteen one-month old rabbits were randomly divided into two groups: Eight rabbits had triamcinolone acetonide (1mg/kg/day) administered IM daily for 21 days (test group) while the remaining eight rabbits received no drug (control group). The rabbits in both groups had a tube bonded to the upper central incisors and a stainless steel helical spring was inserted in tube slot to apply 50 cN distal force. After 3 weeks, the rabbits were sacrificed and the distance between mesial corners of incisors was measured. The incisors are associated tissue was processed for histology and the apical and cervical area of the roots evaluated. An observer who was blind to the study groups evaluated the specimens. Results: All appliance-treated incisors in test and control groups showed evidence of tooth movement. The distance between the incisors was significantly greater in the triamcinolone acetonide treated group compared to the control group (P<0.001). Histological examination revealed an increased number of resorption lacunae and decreased number of cuboidal osteoblastic cells around the apical and cervical area of the Incisor roots in the test compared to the control group (P<0.01). Conclusion: Treatment with triamcinolone acetonide is associated with increased tooth movement in rabbits via increased resorptive activity in the alveolar bone.
    The Journal of clinical pediatric dentistry 04/2014; 38(3):285-289. · 0.34 Impact Factor
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    ABSTRACT: Objective: Orthodontists usually see their young patients once a month for two years, putting them in a position to assess overall growth, development, and health during the most formative years. The objective of this study was to determine orthodontists’ willingness to be trained to function as oral physicians, providing limited primary preventive care. Method: An online questionnaire was developed, pretested, and distributed electronically to 20 orthodontic faculty, 26 orthodontic residents, and 65 fourth year dental students at the University of Illinois at Chicago College of Dentistry. It contained 40 questions about knowledge and attitudes regarding expanded roles for orthodontists, including recognition and/or referral for developmental and eating disorders, mental health and behavior issues including ADHA, autism spectrum disorders, addiction, and substance abuse. Result: Of the 40 respondents, 37.5% were orthodontic faculty, 35.0% were fourth year dental students, and 27.5% were orthodontic residents. More dental students and faculty were willing to function as oral physicians, compared to residents (71.4%, 60.0%, 33.3%, respectively). Fisher's Exact test indicated that more fourth year dental students and faculty were willing to receive additional training to expand their knowledge to manage systemic diseases compared to orthodontic residents (100% compared to 62.5%; p value 0.049). Conclusion: Senior dental students and orthodontic faculty appear to be potentially interested in expansion of orthodontists’ duties to include function as oral physicians. Before changes can occur, the dental faculty, current and future dentists, public, licensing authorities, and other stakeholders need to support the concept of dentists as oral physicians. The results of this study will become the basis for developing a national survey of orthodontic program directors, faculty, and students to suggest an appropriate potential curriculum for training orthodontists to function as oral physicians.
    IADR/AADR/CADR General Session and Exhibition 2013; 03/2013
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    ABSTRACT: Objective: The effect of absence or presence of keratinized mucosa (KM) on long-term peri-implant health remains controversial. Our objective was to systematically review the literature to investigate the influence of KM width on clinical parameters of peri-implant health. Method: Two independent reviewers conducted a search in PubMed and Web of Knowledge, as well as a cross references and hand search of journals, to identify relevant studies. Longitudinal and cross-sectional studies on human subjects reporting KM width as a bivariate (≥ 2 mm and <2 mm) and mean Pocket depth (PD), Bleeding on Probing (BOP), Modified Bleeding Index (mBI), Gingival index (GI), Plaque index (PI), Modified Plaque Index (mPI) and Implant Survival with a minimum follow-up of up to 6 months were included. 16 studies were initially selected, 8 of which were included in the systematic review and 7 in the quantitative analysis. Meta-analyses of eligible studies were performed to ascertain summary effects for differences in previously mentioned parameters among groups of KM width using the mean ± SD for each study. Result: Pooled analyses showed that GI, PI and mPI were significantly higher in the group with KM width of <2 mm, while mBI was marginally significant. On the contrary, PD was not significantly different between the two groups (p>0.05). Differences in implant survival rate and BOP could not be analyzed due to limited data availability. Heterogeneity was highly significant among the pooled studies for all investigated variables. There was no indication of publication bias and sensitivity analysis did not result in the significant modification of the results by any of the studies. Conclusion: Lack of adequate KM around implants is associated with clinical parameters of inflammation. This suggests that limited KM width might jeopardize long-term peri-implant health, however the predictive value of KM width is limited based on the selected evidence.
    IADR/AADR/CADR General Session and Exhibition 2013; 03/2013
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    ABSTRACT: Purpose: The aim of this systematic review was to investigate the effect of keratinized mucosa width (KMW) on clinical parameters of peri-implant health and stability. Materials and Methods: Two independent reviewers conducted a comprehensive search to identify studies on human subjects reporting KMW as a bivariate factor (≥ 2 mm and < 2 mm), along with mean pocket depth (PD), bleeding on probing (BOP), modified Bleeding Index (mBI), Gingival Index (GI), Plaque Index (PI), modified PI (mPI), and implant survival with a minimum follow-up of 6 months after implant loading. Eight studies were included in the systematic review and seven in the metaanalyses to ascertain summary effects for differences in the aforementioned parameters among groups of KMW. Results: Pooled analyses showed that GI, PI, and mPI were significantly higher in the group with KMW of < 2 mm, while mBI was also higher but only marginally significant. In contrast, PD was not significantly different between the two groups. Differences in BOP and implant survival rate could not be analyzed because of limited data availability. Heterogeneity was highly significant among the pooled studies for all investigated variables. Conclusion: Reduced KMW around implants appears to be associated with clinical parameters indicative of inflammation and poor oral hygiene. However, based on the selected evidence, the predictive value of KMW is limited.
    The International journal of oral & maxillofacial implants 01/2013; 28(6):1536-45. · 1.91 Impact Factor
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    ABSTRACT: Edentulism is an important issue and will remain so due to high numbers of edentate individuals worldwide. For many years, complete dentures have been the only treatment option for this population. Implant overdentures have been shown to have many advantages over conventional complete dentures. However, although dissatisfied with their mandibular dentures, some edentate elders are reluctant to undergo even simple implant treatment due to factors such as cost and fear of surgery. To address these obstacles, this paper reports on a review of small-diameter implant (SDI) studies that were performed in the last two decades. The aim of this study is to (i) determine the survival of narrow diameter implants, (ii) determine whether survival is dependent on whether these implants are placed using a flap or flapless approach, and (ii) determine whether there is a relationship between length and implant survival in SDIs. In this review, studies were included that (i) involve implants with 3.5 mm diameter or less, (ii) have a randomized clinical trial, retrospective or prospective cohort design with human subjects, (iii) provide a follow up duration of at least 5 months following implant placement, (iv) include data on the survival rate of the implants. Forty one studies meeting the above criteria were published between 1993 and 2011 using SDIs from a variety of companies and surface characteristics with diameters of 1.8 mm to 3.5 mm and lengths of 8 mm to 18 mm. A total of 10,093 SDIs were inserted in approximately 2762 patients. Twenty-six studies involved flap reflection techniques for implant placement, six studies used a flapless technique and two studies used both techniques; in the remaining studies, the technique was not specified. Follow up duration varied from 5 months to over 9 years. The survival rate reported in all screened studies was over 90%, including eight studies in which a 100% survival rate was reported. In 22 studies, the reported survival rate ranged from 95% to 99.9%. Failure was reported most often in short SDIs (less than or equal 13 mm) (n = 88) compared to longer ones (more than 13 mm). Survival rates reported for SDI are similar to those reported for standard width implants. These survival rates did not appear to differ between studies that used flapless and flap reflection techniques. The failure rate appeared to be higher in shorter SDIs than in longer ones in the studies in which the length of the failed implants was reported. SDIs could be considered for use with fixed restorations and mandibular overdentures, since their success rate appears to be comparable to that of regular diameter implants. They might also be an efficient, low-cost solution for elders who wish to reduce problems with denture instability.
    Clinical Oral Implants Research 02/2012; 23(5):515-25. · 3.43 Impact Factor
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    ABSTRACT: The regenerative surgical treatment of intrabony defects caused by periodontal disease has been examined in several systematic reviews and meta-analyses. The use of bioactive glass (BG) as a graft material to treat intrabony defects has been reported, but all data have not been synthesized and compiled. Our objective was to systematically review the literature on the use of BG for the treatment of intrabony defects and to perform a meta-analysis of its efficacy. A search of PubMed, EMBASE, and Cochrane Database of Systematic Reviews, as well as a manual search of recently published periodontology journals, were conducted to identify randomized controlled trials of the use of BG in the treatment of intrabony and furcation defects. Criteria included publication in English, follow-up duration of ≥6 months, baseline and follow-up measures of probing depth (PD) and clinical attachment levels (CAL) with 95% confidence intervals (CIs), and an appropriate control arm. Twenty-five citations were identified, 15 of which were included in the final analysis. Data, including study methods and results, as well as CONSORT (Consolidated Standards of Reporting Trials) criteria, were extracted from eligible studies and cross-checked by at least two reviewers. Meta-analyses of eligible studies were performed to ascertain summary effects for changes in PD and CAL among experimental and control groups, using the mean change plus standard deviation for each study. Pooled analyses showed that BG was superior to control for both measures: the mean (95% CIs) difference from baseline to follow-up between BG and controls was 0.52 mm (0.27, 0.78, P <0.0001) in reduction for PD and 0.60 mm (0.18, 1.01, P = 0.005) in gain for CAL. Analyses of CAL revealed heterogeneity across studies (I(2) = 60.5%), although studies reporting PD measures were homogeneous (I(2) = 0.00%). CAL heterogeneity appeared secondary to active controls versus open flap debridement (OFD) alone and to defect-type modifying BG treatment success. Per subgroup analyses, the benefit of BG over control treatment was highly significant only in studies comparing BG to OFD (P <0.0001), with mean difference change in CAL being 1.18 mm (95% CI = 0.74, 1.62 mm) between the BG and OFD group. Treatment of intrabony defects with BG imparts a significant improvement in both PD and CAL compared to both active controls and OFD.
    Journal of Periodontology 08/2011; 83(4):453-64. · 2.40 Impact Factor
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    ABSTRACT: The aim of the present retrospective study was to evaluate the local effects of smoking on periodontium and to assess the patterns of periodontitis (pocket depths and attachment loss) in smokers and non-smokers. In this study, records of 126 non-smokers and 51 smokers (≥ 5 cigarettes/day) periodontitis patients were evaluated and probing pocket depth (PPD), clinical attachment level (CAL) and bleeding on probing (BOP) data were collected from clinical patients records. Patients' data were subject to two sample t-tests to assess the difference between the groups and to analysis of variance using the generalized linear model to seek associations between smoking and site positions, age and clinical parameters. The difference between CAL of smokers and non-smokers was greatest at the anterior maxillary palatal sites (P = 0.002) and reached 1 mm. When the effect of different site positions as well as smoking as a between subject variable and age as a co-variate on the attachment level measurements were assessed using analysis of variance, significant effects for smoking, jaw (lower versus upper) and anterior-posterior position as well as age were detected. No significant interactions were found between smoking and any of the three position variables. Lack of interaction between smoking and any of the three position variables indicates that the destructive effects of smoking on the periodontal tissues maybe mainly from systemic side-effects and almost independent of the site position within the mouth, although some additional local effects may be present in areas such as anterior palatal sites.
    International Journal of Dental Hygiene 02/2011; 9(4):291-5. · 0.80 Impact Factor
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    ABSTRACT: Objectives: Alveolar Osteitis (AO) is one of the common complications of third molar extraction. It is characterized by pain occurring between the first and third day postextraction due to disintegration of the intra-alveolar blood clot. Several drugs have been used in the prevention of AO such as chlorhexidine (CHX) rinses as an antiseptic agent. Recently, 0.2% CHX gel has been introduced for intra-alveolar placement of the substance. It has been suggested it has more effect due to direct and prolonged contact. The aim of this study was to evaluate the efficacy of the intra-alveolar use of the 0.2% CHX gel in prevention of AO following the surgery of impacted mandibular third molars. Methods: In this mouth split double-blind randomized clinical trial study, non-smoker patients of both genders (20 patients of each) between the age of 18 and 41 years who had plan to undergo surgery for both impacted mandibular third molars were selected. No patient was taking birth controls. Under local anesthesia both impacted teeth were removed and for each patient 0.2% CHX gel was placed in one socket. In the other socket a Gel placebo was applied, considered as control group. All patients were evaluated on forth and seventh days postoperatively for clinical evaluation of AO and also pain and swelling on given questionnaire, respectively. Results: A 56% decrease in postoperation AO in the gel group was observed (P=0.453). The control group had 12.5% incidence postoperative AO, while the gel group had 5%. The difference was not statistically significant. No statistically significant differences were found in postoperative pain and swelling between two groups. Conclusion: Topical intra-alveolous application of 0.2% CHX gel following the surgery of impacted mandibular third molars may decrease the incidence of AO. To obtain statistically significant results, further studies using more samples are needed.
    Journal of Dental Research 90 (Specific Issue A). 01/2011;
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    ABSTRACT: This study assessed the influence of current oral contraceptive pills on periodontal health in young females. Seventy women ranging in age from 17 to 35 years (mean 24 years) had a comprehensive periodontal examination. Their current and previous oral contraceptive pill use was assessed by a questionnaire. A periodontal assessment was performed that included recording the following: plaque index, gingival index, probing depth, and attachment level at six sites per tooth. The periodontal health of women taking birth control pills for at least two years was compared to that of women not taking an oral contraceptive. The control and test groups were matched for socioeconomic status, age, oral habits, occupation, and educational levels. Although there was no difference in plaque index levels between the two groups, current oral contraceptive pill users had higher levels of gingival inflammation and bleeding on probing. However, no significant differences were found regarding mean probing depths and attachment loss between the two groups. As birth control policies are advocated by most countries, and because oral contraceptives are the most widely used method for birth control, a need exists to assess the effects of oral contraceptives on the periodontal health of young women. Although additional studies are needed to better understand the mechanism of OC-induced gingivitis, female patients should be informed of the oral and periodontal side effects of OCs and the need for meticulous home care and compliance with periodontal maintenance.
    The journal of contemporary dental practice 05/2010; 11(3):033-40.
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    ABSTRACT: The aim of this study was to compare the clinical outcomes of applying Bio-Oss, an anorganic bovine bone xenograft (control group) to the combined use of Bio-Oss and Bio-Gide (a bioabsorbable collagen membrane) (test group) in human mandibular Class II furcation defects. A total of 18 furcations (8 tests and 10 controls) in 14 patients suffering from chronic periodontitis were treated in this randomized clinical trial. Open vertical and horizontal furcation depths (OVFD and OHFD), vertical and horizontal clinical attachment levels (VCAL, HCAL), probing depth (PD) and free gingival marginal level (GML) were among the clinical parameters measured prior and six months after treatment, at re-entry surgery. The data were analysed by statistical tests while a p value less than 0.05 was considered significant. At the surgical re-entry, the mean reduction for OVFD of the control and test groups was 1.9 +/- 1.3 and 2.1 +/- 1.0, and for OHFD 2.1 +/- 0.7 and 2.4 +/- 1.3, respectively. The control and test treatments resulted in significant reductions in PD, VCAL and HCAL measurements at re-entry but there was no statistically significant difference between the two treatments in all soft and hard tissues measurements. This clinical trial failed to demonstrate the superiority of the combined use of Bio-Gide and Bio-Oss to the use of Bio-Oss alone, although both therapies resulted in significant gains in attachment level and bone fill.
    Australian Dental Journal 10/2009; 54(3):220-7. · 1.37 Impact Factor
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    ABSTRACT: Antimicrobial efficacy of three spray disinfectants--0.525 percent sodium hypochlorite (bleach), deconex and Sanosil--was evaluated on contaminated alginate disks. Disks were sprayed eight to 10 times after rinsing in water for 15 seconds. The samples were then placed into plastic bags containing a sterile moist cotton roll for 10 minutes. The use of 0.525 percent sodium hypochlorite sprayed onto the surface of alginate effectively disinfected 96.6 percent of the samples.
    Journal of the California Dental Association 08/2009; 37(7):471-7.
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    ABSTRACT: Introduction: The use of radiotherapy, alone or in conjunction with surgical resection, is common in treating head and neck tumours. However, ionising radiation induces unavoidable changes in the sur-rounding normal tissues, causing severe complications. Therefore, we decided to study different effects of radiotherapy on gingiva and oral mucosa.
    Journal of Radiotherapy in Practice 12/2008;
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    ABSTRACT: The effect of tea, cola, orange juice, and distilled water on the color stability of a porcelain (VITA VMK 95) and a reinforced composite rein (GC Gradia) was evaluated. Standardized specimens for each material was prepared. Specimens from each group were immersed in staining solutions at 50 degree Celsius for 30 days. Tea caused the most significant color change. DeltaE of all of the materials was changed after the immersion in all of the staining solutions during the experimental process.
    Journal of the California Dental Association 10/2008; 36(9):673-80.