Hamdan Bin Mohammed College of Dental Medicine (HBMCDM)

Permanent URI for this communityhttps://mbru-staging.nexuslib.xyz/handle/1/5

Browse

Now showing 1 - 20 of 369

A 24‑month retrospective study of preformed metal crowns: the Hall technique versus the conventional preparation method
(2020) Binladen, H.; Al Halabi, Manal; Kowash, Mawlood; Al Salami, Anas; Hassan Khamis, Amar; Hussein, Iyad
Purpose: Conventional and Hall Technique (HT) Preformed Metal Crowns (PMCs) are used for treatment of carious primary molars. The aim was to evaluate the clinical and radiographic success of conventional and HT PMCs in a postgraduate dental setting. Methods: A retrospective study using patients’ electronic case-notes and radiographic images of carious primary molars treated with either conventional or HT PMCs was conducted to assess clinical and radiographic success/failure. A Kaplan– Meier curve was used to assess PMC survival. Results: 187 PMCs (110 HT and 77 conventional) in 65 children (34 females and 31 males) at 6, 12, 18 and 24 months were assessed. At 24 months, the success rates of conventional and HT PMCs were 97.6% and 93.5%, respectively. Two HT (perforated/abscessed) and four conventional (abscessed) PMCs failures occurred. There was no signifcant diference in success/failure (p=0.362) at 12 months, but the HT was more successful at 24 months (p=0.002) with similar survival times for both methods. Conclusion: HT and conventionally placed PMCs, when placed in a postgraduate paediatric dentistry setting, were clinically and radiographically very successful at 6, 12, 18 and 24 months post operatively with a slightly higher success of the HT at 24 months.
3D bioprinting for in vitro models of oral cancer: Toward development and validation
(2021) Moharamzadeh, Keyvan
Abstract The tumor microenvironment (TME) of oral carcinomas has highly complex contents and a dynamic nature which is difficult to study using oversimplified two-dimensional (2D) cell culture systems. By contrast, three dimensional (3D) in vitro models such as spheroids, organoids, and scaffold-based constructs have been able to replicate tumors three-dimensionality and have allowed a better understanding of the role of various microenvironmental cues in the initiation and progression of cancer. However, the heterogeneity of TME cannot be fully reproduced by these traditional tissue engineering strategies since they are unable to control the organization of multiple cell types in a complex architecture. 3D bioprinting is an emerging field that can be leveraged to produce biomimetic and complex tissue structures. Bioprinting allows for controllable and precise placement of multicomponent bioinks composed of multiple biomaterials, different types of cells, and soluble factors according to the natural compartments of the target tissue, aiming to reproduce the equivalent of the complex tissue. As such, 3D bioprinting provides a unique opportunity to fabricate in vitro tumor models with a complexity similar to that of the in vivo oral carcinoma. This will facilitate a thorough investigation of cellular physiology, cancer progression, and anticancer drug screening with unprecedented control and reproducibility. In this review, we discuss the role of 3D bioprinting in reconstituting oral cancer, the prospects of application to fill the literature gap, and the challenges that need to be addressed in order to exploit this emerging technology for future work in oral cancer research.
3D Printing of Dental Prostheses: Current and Emerging Applications
(2023) Moharamzadeh, Keyvan
Abstract: Revolutionary fabrication technologies such as three-dimensional (3D) printing to develop dental structures are expected to replace traditional methods due to their ability to establish constructs with the required mechanical properties and detailed structures. Three-dimensional printing, as an additive manufacturing approach, has the potential to rapidly fabricate complex dental prostheses by employing a bottom-up strategy in a layer-by-layer fashion. This new technology allows dentists to extend their degree of freedom in selecting, creating, and performing the required treatments. Three-dimensional printing has been narrowly employed in the fabrication of various kinds of prostheses and implants. There is still an on-demand production procedure that offers a reasonable method with superior efficiency to engineer multifaceted dental constructs. This review article aims to cover the most recent applications of 3D printing techniques in the manufacturing of dental prosthetics. More specifically, after describing various 3D printing techniques and their advantages/disadvantages, the applications of 3D printing in dental prostheses are elaborated in various examples in the literature. Different 3D printing techniques have the capability to use different materials, including thermoplastic polymers, ceramics, and metals with distinctive suitability for dental applications, which are discussed in this article. The relevant limitations and challenges that currently limit the efficacy of 3D printing in this field are also reviewed. This review article has employed five major scientific databases, including Google Scholar, PubMed, ScienceDirect, Web of Science, and Scopus, with appropriate keywords to find the most relevant literature in the subject of dental prostheses 3D printing.
3D superimposition of dental casts based on coloured landmark detection using combined computer vision and 3D computer graphics techniques
(2019) Ghoneima, Ahmed
Abstract: The aim of this study was to evaluate the validity and reliability of three-dimensional (3D) landmark-based palatal superimposition of digital dentalmodels using the customized software Ortho Mechanics Sequential Analyzer (OMSA) revised by the addition of a computer vision algorithm. The sample consisted of pre- and post-treatment digital maxillary dental models of 20 orthodontic cases. For each case, the pre- and posttreatment digital models were superimposed using colour detection capabilities of a computer vision algorithm added to OMSA. The same set of parameters was measured on the superimposed 3D data by the two software versions for comparison. Agreement in the superimposition outcomes among the two superimposition methods was evaluated with Dahlberg error (DE), intraclass correlation coefficients (ICCs) using two-way ANOVA mixed model for absolute agreement and Bland–Altman agreement limits (LOA). Repeatability was excellent for all variables (all ICCs over 0.99 with the lower 95% confidence limit ≥0.95). The Dahlberg error (DE) ranged from 0.14mmto 0.36mm. The absolute error did not exceed 0.5mmfor any variable. The results indicate that OMSA with computer vision algorithms offers a valid and reliable tool for 3D landmark-based digital dental model superimposition using colour detection of three reference points marked along the mid-palatal raphe.
Abrasion: A Common Dental Problem Revisited
(2017-02-28) Milosevic, Alexander
Abstract: Dental abrasion is most commonly seen at the cervical necks of teeth, but can occur in any area, even inter-dentally from vigorous and incorrect use of dental floss. Acid erosion has been implicated in the initiation and progress of the cervical lesion, while tooth-brush abrasion has long been held as the prime cause of cervical abrasion. Identification of the risk factors is clearly important in order to modify any habits and provide appropriate advice.
Accuracy and reliability of landmark- based, surface- based and voxel- based 3D cone- beam computed tomography superimposition methods
(2017) Ghoneima, Ahmed
Objectives: To evaluate and compare the accuracy and reliability of 3 different methods of three- dimensional cone- beam computed tomography scans (3D CBCTs) superimpositions: landmark- based, surface- based and voxel- based. Materials and Methods: Pre and post orthodontic treatment CBCTs (T1 and T2) of 20 subjects with a mean age of 11 years were obtained. Seven points on the zygomatic arch and supraorbital region were selected to perform landmark- based superimposition. Surface- based and voxel- based superimpositions were performed using the anterior cranial base as a reference. Each superimposition method of T1 and T2 scans was repeated twice to assess the reliability. Accuracy of each technique was tested by superimposing duplicated sets of T1 scans. A total of 11 landmarks on the anterior cranial base, maxilla and mandible were located, and deviations of these landmarks on superimposed data were quantified to assess reliability and accuracy of all superimpositions. Results: There were no significant differences from zero when duplicated sets of T1 scans were superimposed using surface- based and voxel- based methods. Statistical significant differences were detected in several parameters when evaluating the accuracy of the landmark superimposition. Superimposition of T1 and T2 scans for testing the reliability revealed intraclass correlation coefficients greater than 0.90 for all measurements except for ACP- x and PNS- y of landmark- based method as well as ANS- x of voxel- based method. Conclusions: Surface- based and voxel- based superimposition methods using the anterior cranial base as a reference structure were accurate and reliable in detecting changes in landmark positions when superimposing. Landmark- based superimposition method was reliable but less accurate than the other methods.
Accuracy of three-dimensional dental resin models created by fused deposition modeling, stereolithography, and Polyjet prototype technologies: A comparative study
(2018) Ghoneima, Ahmed
Objectives: The aim of this study was to assess the dimensional accuracy of fused deposition modeling (FDM)–, Polyjet-, and stereolithography (SLA)–produced models by comparing them to traditional plaster casts. Materials and Methods: A total of 12 maxillary and mandibular post treatment orthodontic plaster casts were selected from the archives of the Orthodontic Department at the Indiana University School of Dentistry. Plaster models were scanned, saved as stereolithography files, and printed as physical models using three different three-dimensional (3D) printers: Makerbot Replicator (FDM), 3D Systems SLA 6000 (SLA), and Objet Eden500V (Polyjet). A digital caliper was used to obtain measurements on the original plaster models as well as on the printed resin models. Results: Comparison between the 3D printed models and the plaster casts showed no statistically significant differences in most of the parameters. However, FDM was significantly higher on average than were plaster casts in maxillary left mixed plane (MxL-MP) and mandibular intermolar width (Md-IMW). Polyjet was significantly higher on average than were plaster casts in maxillary intercanine width (Mx-ICW), mandibular intercanine width (Md-ICW), and mandibular left mixed plane (MdL-MP). Polyjet was significantly lower on average than were plaster casts in maxillary right vertical plane (MxR-vertical), maxillary left vertical plane (MxL-vertical), mandibular right anteroposterior plane (MdR-AP), mandibular right vertical plane (MdR-vertical), and mandibular left vertical plane (MdL-vertical). SLA was significantly higher on average than were plaster casts in MxL-MP, Md-ICW, and overbite. SLA was significantly lower on average than were plaster casts in MdR-vertical and MdL-vertical. Conclusions: Dental models reconstructed by FDM technology had the fewest dimensional measurement differences compared to plaster models.
Acid erosion: an increasingly relevant dental problem. Risk factors, management and restoration
(2017) Milosevic, Alex
Abstract: A review of risk factors and management of acid erosion. Particular emphasis is placed on the use of direct composite as a reversible and relatively straightforward restorative option.
AI-based automated pre-processing and classification of impacted maxillary canines in panoramic radiographs
(2024) Abdulkreem, Ali; Alzaabi, Hessa; Alali, Kawther; Gonzalez, Angela; Chaudhry, Jahanzeb; Prasad, Sabarinath
Abstract: Objectives: Automating the digital workflow for diagnosing impacted canines using panoramic radiographs (PRs) is challenging. This study explored feature extraction, automated cropping, and classification of impacted and non-impacted canines as a first step. Methods: A convolutional neural network (CNN) with SqueezeNet architecture was first trained to classify two groups of PRs (91with, and 91without impacted canines) on the MATLAB programming platform. Based on results, the need to crop the PRs was realized. Next, artificial intelligence (AI) detectors were trained to identify specific landmarks (maxillary central incisors, lateral incisors, canines, bicuspids, nasal area, and the mandibular ramus) on the PRs. Landmarks were then explored to guide cropping of the PRs. Finally, improvements in classification of automatically cropped PRs was studied. Results: Without cropping, the area under the curve (AUC) of the Receiver Operating Characteristic (ROC) curve for classifying impacted and non-impacted canine was 84%. Landmark training showed that detectors could correctly identify upper central incisors and the ramus in ~98% of PRs . The combined use of the mandibular ramus and maxillary central incisors as guides for cropping yielded the best results (~10% incorrect cropping). When automatically cropped PRs were used, the AUC-ROC improved to 96%. Conclusion: AI algorithms can be automated to pre-process PRs and improve the identification of impacted canines.
Airflow for initial nonsurgical treatment of peri-implantitis: A systematic review and meta-analysis
(2021) Atieh, Momen; Almatrooshi, Aisha; Shah, Maanas S.; Hannawi, Haifa
Background: Nonsurgical treatment of peri-implantitis may help in reducing microbial load and inflammatory parameters. The potential clinical benefits of using different treatment approaches, in the initial nonsurgical treatment phase, particularly the airflow, are still not clear. The aim of this systematic review and meta-analyses was to evaluate the outcomes of nonsurgical treatment of peri-implantitis using airflow method in terms of changes in periodontal parameters, peri-implant marginal bone level, postoperative pain/discomfort, and patient satisfaction. Methods: Electronic databases were searched to identify randomized controlled trials (RCTs) that compared airflow with mechanical debridement using ultrasonic/curettes. The risk of bias was assessed using the Cochrane Collaboration's Risk of Bias tool. Data were analyzed using a statistical software program. Results: A total of 316 studies were identified, of which, five RCTs with 288 dental implants in 174 participants were included. Overall meta-analysis showed more reduction in probing pocket depths at 1–3 months (mean difference [MD] 0.23; 95% confidence interval [CI] -0.50–0.05; p = 0.10) and 6 months (MD -0.04; 95% CI -0.34 to 0.27; p = 0.80) in favor of airflow, but the difference was not statistically significant. The use of airflow was associated with significant reduction in bleeding on probing and increase in peri-implant mucosal recession. The differences in plaque score, peri-implant marginal bone level changes, and patient reported outcomes between airflow and mechanical debridement were not statistically significant. Conclusions: The short-term clinical and radiographic outcomes following nonsurgical treatment of peri-implantitis using airflow or mechanical debridement were comparable. The airflow has short-term positive effects on reducing bleeding on probing. Further evidence from RCTs are still required to substantiate the current findings.
Alveolar ridge preservation in extraction sockets of periodontally compromised teeth: A systematic review and meta-analysis.
(2022-07) Atieh, Momen; Alnaqbi, Maitha; Abdunabi, Farida
Objectives: Alveolar ridge preservation (ARP) procedures can limit bone changes following tooth extraction. However, the role of ARP in periodontally compromised socket lacks strong scientific evidence. The aim of this systematic review and meta analysis was to evaluate the outcomes of ARP following extraction of periodontally compromised teeth in comparison with extraction alone in terms of hard tissue changes, need for additional augmentation at the time of implant placement, and patient-reported outcomes. Material and Methods: Electronic databases were searched to identify randomized controlled trials (RCTs) that compared ARP in periodontally compromised sockets with spontaneous socket healing. The risk of bias was assessed using the Cochrane Collaboration's risk of bias tool. Results: Five studies with 134 extraction sockets in 126 participants were included. Of these, ARP was performed in 77 sites, while the remaining sites were intentionally left to heal without any ARP treatment. The follow-up time varied between 6 and 12 months. Overall meta-analysis showed significant differences in changes in ridge height (mean difference (MD) −0.95; 95% confidence interval (CI) −1.43 to −0.47; p = .0001) and bone volume (MD −38.70; 95% CI −52.17 to −25.24; P<.0001) in favor of ARP. The use of ARP following extraction of periodontally compromised tooth was also associated with significantly less need for additional bone grafting at the time of implant placement. Conclusions: Within the limitation of this review, ARP following extraction of periodontally compromised teeth may have short-term positive effects on alveolar ridge height and bone volume and minimize the need for additional augmentation procedures. However, the evidence is of very low to low certainty.
Amelogenesis imperfecta and anterior open bite: Etiological, classification, clinical and management interrelationships
(2014-03) Athanasiou, Athanasios E
Abstract: Although amelogenesis imperfecta is not a common dental pathological condition, its etiological, classification, clinical and management aspects have been addressed extensively in the scientific literature. Of special clinical consideration is the frequent co-existence of amelogenesis imperfecta with the anterior open bite. This paper provides an updated review on amelogenesis imperfecta as well as anterior open bite, in general, and documents the association of these two separate entities, in particular. Diagnosis and treatment of amelogenesis imperfecta patients presenting also with anterior open bite require a lengthy, comprehensive and multidisciplinary approach, which should aim to successfully address all dental, occlusal, developmental, skeletal and soft tissue problems associated with these two serious clinical conditions.
Analgesics Misuse: a Problem among Saudi Female Students
(2018) Omer, Amar Hassan Khamis Mohammed
Background: The research aims to assess the knowledge and attitude of female high school students towards analgesics use. The research is a result of concerns raised by high school advisors in regards to the analgesics knowledge and frequency of use amongst students. The findings of the study could be useful for targeted awareness campaigns or sessions for students and the community. Methods and Material: A questionnaire was developed by the investigator and validated by two experts. All students in the third grade were included in the study. The total number of students was 488. All data were collected by the investigator through direct contact with the students. Statistical Analysis Used: Analysis of Variance, t-test, and univariate regression model were used as appropriate. Results: Reliability of the questionnaire was found to be 100%. The mean age of students was 17.4± 0.8 years. A total of (88.3%) of the students reported use of analgesics. Paracetamol was the drug of choice for almost half of the students (49.2%). The study showed repeated analgesics usage among the students, where (12%) used medication daily, (14.4%) weekly and (72.6%) had monthly usage. Only two variables affected the prevalence of analgesics usage namely ―analgesics given to students by the people surrounding them‖ and ―analgesics are the immediate choice when the students feel any pain‖. Conclusion: Self-medication is prevalent and common among adolescent female students in Safwa city, Eastern Province Saudi Arabia. Moreover, the knowledge of analgesics side effects was inadequate which led to widespread misuse among the targeted population.
Anterior teeth root inclination prediction derived from digital models: A comparative study of plaster study casts and CBCT images
(2018) Dastoori, Mahmoud; Athanasiou, Athanasios E
Background: To assess the accuracy of digital models generated using commercially available software to predict anterior teeth root inclination characteristics and compare the results to relevant data obtained from CBCT images. Material and Methods: Following sample size calculation and after application of inclusion and exclusion criteria, pre-treatment maxillary and mandibular plaster models and the corresponding CBCT scans of 31 patients attending a private orthodontic clinic were selected. The subjects were 10 males and 21 females with age range 12 to 40 years. Plaster models were scanned using the high resolution mode of an Ortho Insight 3D scanner and CBCT scans were taken using a Kodak 9500 Cone Beam 3D System machine. The teeth on the digital scans were segmented and virtual roots were predicted and constructed by the Ortho Insight 3D software. The long axes of the predicted roots and the actual roots, as segmented from the CBCT images, were computed using best-fit lines. The inter-axis angle was used to assess error in root inclination prediction by the software. Mann-Whitney and Kruskal-Wallis tests were used. Intra-examiner error was evaluated using the Bland-Altman method. Results: The maximum disparity in angle between images derived from digital models and CBCT data was almost 40 degrees (upper left canine). The upper and lower canines produced the worst results, followed by the lower lateral incisors. The upper central incisors showed the best results, although the maximum angle of difference exceeded 20 degrees (with the median around 8 degrees). Conclusions: Root morphology imaging prediction is not a primary function of this software and this study confirmed its limitation as a sole tool in routine clinical applications. At present these predictions cannot be considered accurate or reliable unless correlated clinically with a radiographic image.
Antimicrobial Activity of Phytic Acid: An Emerging Agent in Endodontics
(2021) Nassar, Rania; Naidoo, Nerissa; Kaklamanos, Eleftherios G; Senok, Abiola
Background: Phytic acid (IP6) is a promising and emerging agent, and because of its unique structure and distinctive properties, it lends itself to several applications in dentistry. Recently, IP6 was proposed as a potential chelating agent in endodontics. However, there is limited knowledge regarding its antimicrobial and antibiofilm effectiveness. The aims of this study, were therefore to evaluate the antimicrobial and antibiofilm activities of IP6 against a range of microbial species and compare these with ethylenediaminetetraacetic acid (EDTA) and sodium hypochlorite (NaOCl). The contact time required for IP6 to exert its bactericidal effect on Enterococcus faecalis was also determined. Methods: The inhibitory and biocidal activities of IP6, EDTA and NaOCl were assessed using a broth microdilution assay against 11 clinical and reference strains of bacteria and a reference strain of Candida albicans. The contact time required for various IP6 concentrations to eliminate planktonic cultures of E. faecalis was determined using a membrane filtration method according to BS-EN-1040:2005. IP6 bactericidal activity was also evaluated using fluorescent microscopy, and the antibiofilm activity of the test agents was also determined. Results: IP6 was biocidal against all tested microorganisms. At concentrations of 0.5%, 1% and 2%, IP6 required 5 min to exert a bactericidal effect on E. faecalis, while 5% IP6 was bactericidal after 30 s. IP6 also eradicated biofilms of the tested microorganisms. In conclusion, IP6 had notable antimicrobial effects on planktonic and biofilm cultures and exhibited rapid bactericidal effects on E. faecalis. This research highlighted, for the first time the antimicrobial and antibiofilm properties of IP6, which could be exploited, not only in dental applications, but also other fields where novel strategies to counter antimicrobial resistance are required.
Apical root resorption of deciduous teeth: a review
(2016) Athanasiou, Athanasios E
Abstract: The resorption of deciduous teeth is considered a necessary process leading to their exfoliation. In most cases it begins in the apical root region and proceeds coronally, yet some local or systemic factors can influence this normal procedure. The aim of this article is to review current concepts regarding apical root resorption of deciduous teeth, to update awareness on factors possibly affecting the physiologic process, and to discuss proposed treatment options. A novel classification is adopted by the review authors, which comprehensively discriminates among the various types of root resorption based on physiologic timing or the various etiologic factors of pathologic appearance. The article reviews the (a) normal physiologic resorption, (b) delayed physiologic resorption, (c) pathologic resorption caused by systemic or general factors, and (d) pathologic resorption caused by local factors. The above-mentioned mechanisms are explained with regard to the management of the problem by the clinician where possible.
Application of microneedle patches for drug delivery; doorstep to novel therapies
(2022-03) Moharamzadeh, Keyvan
Abstract: In the past decade, microneedle-based drug delivery systems showed promising approaches to become suitable and alternative for hypodermic injections and can control agent delivery without side effects compared to conventional approaches. Despite these advantages, the procedure of microfabrication is facing some difficulties. For instance, drug loading method, stability of drugs, and retention time are subjects of debate. Besides, the application of novel refining fabrication methods, types of materials, and instruments are other issues that need further attention. Herein, we tried to summarize recent achievements in controllable drug delivery systems (microneedle patches) in vitro and in vivo settings. In addition, we discussed the influence of delivered drugs on the cellular mechanism and immunization molecular signaling pathways through the intradermal delivery route. Understanding the putative efficiency of microneedle patches in human medicine can help us develop and design sophisticated therapeutic modalities.
Are asthma and allergy associated with increased root resorption following orthodontic treatment? A meta-analysis
(2023) Al-Saqi, Reem Kais; Athanasiou, Athanasios E; Kaklamanos, Eleftherios G
Objective: The aim of this study is to systematically investigate the available evidence from human studies regarding the association of asthma and/or allergy with EARR. Materials and methods: Unrestricted searches in 6 databases and manual searching were performed up to May 2022. We looked for data on EARR after orthodontic treatment in patients with/without asthma or allergy. Relevant data were extracted, and the risk of bias was assessed. An exploratory synthesis was carried out using the random effects model, and the overall quality of the evidence was assessed with the Grades of Recommendation, Assessment, Development, and Evaluation. Results: From the initially retrieved records, nine studies met the inclusion criteria (three cohort and six case-control). Overall, increased EARR was observed in the individuals with allergies in their medical history (Standardised Mean Difference [SMD]: 0.42, 95% Confidence Interval [CI]: 0.19 to 0.64). No difference in EARR development was observed among individuals with or without a medical history of asthma (SMD: 0.20, 95% CI: -0.06 to 0.46). The quality of available evidence, excluding studies at high risk, was rated as moderate for the exposure to allergy, and low for the exposure to asthma. Conclusion: Increased EARR was noted in individuals with allergies compared to the control group, while no difference was observed for individuals with asthma. Until more data become available, good practice would suggest that it is important to identify patients with asthma or allergy and consider the possible implications.
Are orthodontic landmarks and variables in digital cephalometric radiography taken in fixed and natural head positions reliable?
(2020) Athanasiou, Athanasios E
Objective: The purpose of the study was to evaluate the reliability of the most common landmarks and variables in digital lateral cephalometric radiographies in fixed and natural head positions. Materials and methods: Twenty-one patients with anterior or distal displacement of the mandible treated in the Postgraduate Orthodontic Clinic of the Aristotle University of Thessaloniki had a digital lateral cephalometric radiography in fixed and in natural head position. The images where digitized. The main investigator and 6 examiners, digitized 61 landmarks and analysed 34 var- iables. We examined the intra-observer and inter-observer variability. Results: There was a significant difference in X-axis in the distribution (hence the mean results) according to the reliability of the landmarks and in only 2 variables in digital lateral cephalograms between fixed and natural head position. Conclusions: Cephalometric landmarks and variables showed reliability in digital lateral cephalo- metric radiography in fixed and natural head position. In lateral cephalograms taken in fixed head position an anterior inclination of the head was noticed compared to those in natural head position.
Assessing small study effects and publication bias in orthodontic meta-analyses: a meta-epidemiological study
(2014-05) Athanasiou, Athanasios E
Objective: The aim of this study was to examine the presence and extent of small study effects and publication bias in meta-analyses (MAs) based on orthodontic studies. Materials and methods: Following an extensive literature search, 25 MAs including 313 studies were identified and were possible to be re-analyzed. For the assessment of publication bias, contour-enhanced funnel plots were examined and their symmetry was tested using the Begg and Mazumdar rank correlation and Egger's linear regression tests. Robustness of MAs' results to publication bias was examined by Rosenthal's failsafe N, and adjusted effect sizes were calculated after consideration of publication bias using Duval and Tweedie's "trim and fill" procedure. Results: Only few of the originally published MAs assessed the existence and effect of publication bias and some only partially. Inspection of the funnel plots indicated possible asymmetry, which was confirmed by Begg and Mazumdar's test in 12 % and by Egger's test in 28 % of the MAs. According to Rosenthal's criterion, 62 % of the MAs were robust, while adjusted effect estimates with unpublished studies differed from little to great from the unadjusted ones. Pooling of Egger's intercepts of included MAs indicated that evidence of asymmetry was found in the orthodontic literature, which was accentuated in medical journals and in diagnostic MAs. Conclusions: Small study effects and publication bias can often distort results of MAs. Since indications of publication bias in orthodontics were found, the influence of small trials on estimated treatment effects should be routinely and more carefully assessed by authors conducting MAs.

Browse

Browsing Hamdan Bin Mohammed College of Dental Medicine (HBMCDM) by Title