Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 15 3 2018 06 13 137 142 EN Sibel Cetik Professor, Laboratory of Physiology and Pharmaceutics, School of Medicine, Université Libre de Bruxelles, Brussels, Belgium; Department of Stomatology and Dentistry, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium Marion Vincent Dentist, Department of Stomatology and Dentistry, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium Ramin Atash Professor, Department of Stomatology and Dentistry, Erasmus Hospital, Université Libre de Bruxelles, Brussels, Belgium 2017 06 13 2017 11 23 Objectives: The use of zirconia as a framework for prosthetic restorations is increasing due to its favorable mechanical properties. Zirconia also has remarkable aesthetic properties when used as a framework and covered with a layer of cosmetic ceramic. The aim of this study was to compare the fracture toughness of three types of aesthetic ceramics, namely VITA VM®9, ceraMotion® Zr, and IPS e.max® Ceram. Materials and Methods: Three groups of aesthetic ceramics (n=10) were subjected to three-point bending tests. The force leading to fracture was recorded for each sample to measure the impact of the ceramic type on the solidity of the framework. The type of fracture has not been studied in this work. One-way analysis of variance (ANOVA) was used to statistically analyze the results. Results: The statistical analysis showed significantly different fracture toughness values among the three groups. IPS e.max® showed the lowest fracture toughness (25.42 MPa) compared to VITA VM®9 and ceraMotion® Zr (respectively 40.39 MPa; P<0.001, and 48.78 MPa; P<0.005). Conclusions: Within the limitations of the present study, it can be concluded that aesthetic ceramics play an important role in the fracture toughness of all-ceramic restorations. https://fid.tums.ac.ir/index.php/fid/article/view/1960 https://fid.tums.ac.ir/index.php/fid/article/download/1960/1002

Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 15 3 2018 06 13 187 192 EN Elaheh Beyabanaki Assistant Professor, Department of Prosthodontics, School of Dentistry, Shahid Beheshti University of Medical Sciences, Tehran, Iran Marzieh Alikhasi Associate Professor, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran 2017 06 14 2018 01 24 This article describes the prosthetic treatment of a patient suffering from a hemimaxillary defect after surgical resection of an adenoid cystic carcinoma (ACC) in the palate. The patient had also received therapeutic irradiation. One year after radiotherapy, three implants were placed in the remaining maxillary bone without any bone augmentation. One of the implants failed during the osseointegration period. The implant replacing the failed one also failed during prosthetic procedures. The patient was unwilling to undergo another surgical episode, and the final prosthesis was completed on the two remaining implants. https://fid.tums.ac.ir/index.php/fid/article/view/1964 https://fid.tums.ac.ir/index.php/fid/article/download/1964/1008

Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 15 3 2018 06 13 143 150 EN Fariborz Vafaee Associate Professor, Implant Research Center, Department of Prosthodontics, School of Dental Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Bijan Heidari Assistant Professor, Implant Research Center, Department of Prosthodontics, School of Dental Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Masoumeh Khoshhal Assistant Professor, Implant Research Center, Department of Periodontics, School of Dental Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Amirarsalan Hooshyarfard Postgraduate Student, Department of Periodontics, School of Dental Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Mahmoud Izadi Assistant Professor, Department of Prosthodontics, School of Dental Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran Armaghan Shahbazi Postgraduate Student, Department of Prosthodontics, School of Dental Medicine, Hamadan University of Medical Sciences, Hamadan, Iran Abbas Moghimbeigi Professor, Modeling of Noncomunicable Disease Research Center, Department of Biostatistics, Faculty of Public Health, Hamadan University of Medical Sciences, Hamadan, Iran 2017 03 03 2018 04 03 Objectives: Obtaining an adequate ceramic thickness to mask the substructure color is not always feasible, and appropriate use of a cement may be the only solution. This study aimed to evaluate the effect of the color of Variolink II resin cement on the final color of lithium disilicate glass ceramic restorations. Materials and Methods: In this in-vitro study, 90 discs of IPS e.max Press ceramic were evaluated. The ceramic discs were cemented to composite and amalgam blocks. The effect of the cement color and substructure on the final color of ceramic was analyzed by calculating the color change (∆E) value using a spectrophotometer. Data were analyzed via three-way analysis of variance (ANOVA) and Tukey’s test. Results: The cement color had a statistically significant effect on the final color of ceramic (P≤0.001). The white, yellow, and translucent cements caused the highest color change (ΔE=4.558, 3.308, and 2.649, respectively). The effect of composite substructure and the yellow cement on the final color was less prominent compared to other combinations of cement and substructure (ΔE=2.043). The white cement over amalgam substructure showed the greatest effect on the final color (ΔE=4.890). The ΔE in HO group was less than that of other combinations (P<0.05), and the greatest ΔE was reported in MO group with the white cement (∆E=6.255). Conclusions: The final color of the restoration is influenced by the cement color. Therefore, when IPS e.max Press is used over a metal core, it is recommended to use a cement with an HO ceramic. https://fid.tums.ac.ir/index.php/fid/article/view/1772 https://fid.tums.ac.ir/index.php/fid/article/download/1772/1003

Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 15 3 2018 06 13 193 196 EN Zahra Enshaei Assistant Professor, Dental Research Center, Department of Pediatric Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran Maede Ghasemi Assistant Professor, Dental Materials Research Center, Department of Operative Dentistry, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran 2017 08 08 2017 12 22 The management of traumatic dental injuries as well as crown-root fractures is always challenging in everyday general dental practice. A number of treatment modalities are available for crown-root fractures, depending on the position, extent and severity of the fracture. The aim of this case report was to describe a clinical case of rehabilitation of a complicated crown-root fracture of the maxillary left central incisor, successfully treated by a multidisciplinary approach including orthodontic extrusion. The final result was esthetically pleasant and periodontally sound in the follow ups. https://fid.tums.ac.ir/index.php/fid/article/view/2090 https://fid.tums.ac.ir/index.php/fid/article/download/2090/1009

Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 15 3 2018 06 13 151 160 EN Sholeh Ghabraei Assistant Professor, Department of Endodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Behnam Bolhari Associate Professor, Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Department of Endodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Mohammad Marvi Sabbagh Dentist, Private Practice, Tehran, Iran Mahsa Sobhi Afshar Postgraduate Student, Department of Endodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran 2017 07 05 2018 01 30 Objectives: The purpose of this in-vitro study was to determine and compare the shortest period needed for a triple antibiotic paste (TAP) and calcium hydroxide (Ca(OH)2) plus 2% chlorhexidine (CHX) to eradicate the biofilm of Enterococcus faecalis (EF) from the root canal system. Materials and Methods: Sixty-five extracted single-rooted human teeth with straight root canals were selected. The crowns were cut from the cementoenamel junction (CEJ), and canal preparations were done by step-back technique. The smear layer was removed by 17% ethylenediaminetetraacetic acid (EDTA) and 5.25% sodium hypochlorite (NaOCl). Afterwards, the samples were sterilized with gamma ray and were placed inside microtubes for one week. During this week, the teeth were infected with EF. Then, a TAP and Ca(OH)2 mixed with 2% CHX were inserted into the canals. The roots were cut longitudinally, and dentin chips were collected from the apical part of the roots by a round bur to the depth of 400 μm. The vital bacterial load was assessed by counting the numbers of colony-forming units (CFUs). Results: The paste of Ca(OH)2 mixed with 2% CHX was able to eradicate the EF biofilm in three days. The TAP was able to eradicate the biofilm of EF in seven days. Conclusions: It seems that Ca(OH)2 mixed with 2% CHX is more potent than the TAP against EF biofilm. https://fid.tums.ac.ir/index.php/fid/article/view/2033 https://fid.tums.ac.ir/index.php/fid/article/download/2033/1004

Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 15 3 2018 06 13 161 168 EN Sarvin Sarmadi Assistant Professor, Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Javad Chalipa Assistant Professor, Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Behrad Tanbakuchi Assistant Professor, Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Maryam Javaheri Mahd Postgraduate Student, Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Maryam Nasiri Postgraduate Student, Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Mohammad Reza Mehtari Dentist, Private Practice, Tehran, Iran 2017 08 04 2017 12 26 Objectives: Cleft lip and palate (CLP) is the most common congenital anomaly of the head and neck region. The upper airway in CLP patients is affected by retarded maxillary growth. Small size of the nasopharynx can also lead to mouth breathing. This study aimed to compare the size of nasopharynx and adenoids in non-syndromic unilateral CLP (NSUCLP) patients and healthy controls two-dimensionally on lateral cephalograms. Materials and Methods: This retrospective study was performed on 30 children with NSUCLP (mean age of 11.3 years) and 30 sex- and age-matched healthy controls with class I skeletal relationship. The bony boundaries of the nasopharynx, nasopharyngeal airway and adenoids were outlined on lateral cephalograms and their surface area was calculated and compared between the two groups. The percentage of nasopharynx occupied by the adenoids was calculated for each individual and compared between the two groups using independent t-test. Results: Size of nasopharynx in NSUCLP children was significantly smaller than that in healthy controls (P=0.0001). Size of adenoids was significantly larger in NSUCLP children (P=0.0001). Size of nasopharyngeal airway was smaller in NSUCLP patients than controls (P=0.0001). Percentage of nasopharynx occupied by the adenoids was significantly greater in NSUCLP patients (P=0.0001). Conclusions: The size of nasopharynx is smaller while the size of adenoids is larger in NSUCLP children compared to healthy controls; this can lead to mouth breathing and velopharyngeal incompetence. https://fid.tums.ac.ir/index.php/fid/article/view/2080 https://fid.tums.ac.ir/index.php/fid/article/download/2080/1005

Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 15 3 2018 06 13 169 177 EN Maryam Pourhajibagher Researcher, Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran Nasim Chiniforush Researcher, Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran Abbas Monzavi Professor, Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Hamidreza Barikani Researcher, Dental Implant Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran Mohammad Moein Monzavi Dentist, Private Practice, Tehran, Iran Shaghayegh Sobhani Dentist, Private Practice, Tehran, Iran Sima Shahbi Professor, Laser Research Center of Dentistry, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Department of Dental Biomaterials, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Abbas Bahador Associate Professor, Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran 2017 11 12 2018 02 06 Objectives: Periodontitis is an inflammation of periodontal tissues that is tment of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Allahyar Geramy Professor, Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran; Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Farhood Najafi Assistant Professor, Department of Resin and Additives, Institute for Color Science and Technology, Tehran, Iran Soolmaz Heidari PhD Candidate, Department of Dental Biomaterials, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Hamid Golshahi Postgraduate Student, Department of Orthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran 2017 07 05 2017 08 09 Objectives: This study sought to assess the effect of quaternary ammonium salt (QAS) on shear bond strength of orthodontic brackets to enamel. Materials and Methods: In this in vitro experimental study, 0, 10, 20 and 30% concentrations of QAS were added to Transbond XT primer. Brackets were bonded to 60 premolar teeth using the afore-mentioned adhesive mixtures, and the shear bond strength of the four groups (n=15) was measured using a universal testing machine. After debonding, the adhesive remnant index (ARI) score was determined under a stereomicroscope. Data were analyzed using one-way ANOVA. Results: The mean and standard deviation of shear bond strength of the control and 10%, 20% and 30% groups were 23.54±6.31, 21.81±2.82, 20.83±8.35 and 22.91±5.66 MPa, respectively. No significant difference was noted in shear bond strength of the groups (P=0.83). Study groups were not different in terms of ARI scores (P=0.80). Conclusions: The results showed that addition of QAS to Transbond XT primer had no adverse effect on shear bond strength of orthodontic brackets. https://fid.tums.ac.ir/index.php/fid/article/view/2029 https://fid.tums.ac.ir/index.php/fid/article/download/2029/957

Tehran University of Medical Sciences Frontiers in Dentistry 2676-296X 14 3 2017 10 18 165 172 EN Fariborz Vafaee Associate Professor, Implant Research Center, Department of Prosthodontics, School of Dental Medicine, Hamedan University of Medical Sciences, Hamedan, Iran Farnaz Firouz Assistant Professor, Department of Prosthodontics, School of Dental Medicine, Hamedan University of Medical Sciences, Hamedan, Iran Masoumeh Khoshhal Assistant Professor, Implant Research Center, Department of Periodontics, School of Dental Medicine, Hamedan University of Medical Sciences, Hamedan, Iran Amirarsalan Hooshyarfard Postgraduate Student, Department of Periodontics, School of Dental Medicine, Hamedan University of Medical Sciences, Hamedan, Iran Armaghan Shahbazi Postgraduate Student, Department of Prosthodontics, School of Dental Medicine, Hamedan University of Medical Sciences, Hamedan, Iran Ghodratollah Roshanaei Associate Professor, Modeling of Noncommunicable Diseases Research Center, Department of Biostatistics and Epidemiology, School of Public Health, Hamedan University of Medical Sciences, Hamedan, Iran 2017 06 01 2017 08 22 Objectives: Zirconia restorations have been suggested as a more durable and more appealing alternative to metal restoratio