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Artificial Intelligence and Ethics in Dentistry: A Scoping Review
(Sage Publications Inc, 2021) Morch, C. M.; Atsu, Saadet; Cai, W.; Li, X.; Madathil, S. A.; Liu, X.; Mai, V.
Dentistry increasingly integrates artificial intelligence (AI) to help improve the current state of clinical dental practice. However, this revolutionary technological field raises various complex ethical challenges. The objective of this systematic scoping review is to document the current uses of AI in dentistry and the ethical concerns or challenges they imply. Three health care databases (MEDLINE [PubMed], SciVerse Scopus, and Cochrane Library) and 2 computer science databases (ArXiv, IEEE Xplore) were searched. After identifying 1,553 records, the documents were filtered, and a full-text screening was performed. In total, 178 studies were retained and analyzed by 8 researchers specialized in dentistry, AI, and ethics. The team used Covidence for data extraction and Dedoose for the identification of ethics-related information. PRISMA guidelines were followed. Among the included studies, 130 (73.0%) studies were published after 2016, and 93 (52.2%) were published in journals specialized in computer sciences. The technologies used were neural learning techniques for 75 (42.1%), traditional learning techniques for 76 (42.7%), or a combination of several technologies for 20 (11.2%). Overall, 7 countries contributed to 109 (61.2%) studies. A total of 53 different applications of AI in dentistry were identified, involving most dental specialties. The use of initial data sets for internal validation was reported in 152 (85.4%) studies. Forty-five ethical issues (related to the use AI in dentistry) were reported in 22 (12.4%) studies around 6 principles: prudence (10 times), equity (8), privacy (8), responsibility (6), democratic participation (4), and solidarity (4). The ratio of studies mentioning AI-related ethical issues has remained similar in the past years, showing that there is no increasing interest in the field of dentistry on this topic. This study confirms the growing presence of AI in dentistry and highlights a current lack of information on the ethical challenges surrounding its use. In addition, the scarcity of studies sharing their code could prevent future replications. The authors formulate recommendations to contribute to a more responsible use of AI technologies in dentistry.
Geriatrik hastalarda protetik tedavi alternatifleri
(2010) Baran, İlgi; Bulut, Ali Can
Çiğneme sisteminde normal yaşlanma değişiklikleri, dişlerde atrisyon, mukozada elastikiyet kaybı, çiğneme kaslarının hacminde azalma, temporomandibular eklemde artrit, tat duyusunda ve tükürük akışında azalma ve periodontal bağlarda kayıp olarak özetlenebilir. Yaşlılığın doğal sonucu olarak ortaya çıkan bu değişiklikler bazen sistemik rahatsızlıkların varlığında daha da belirgin izlenebilir. Çiğneme etkinliği ve estetik görünümün uzun yaşam boyunca devamlılığının sağlanması amacıyla gereken protetik yaklaşımlar genel sağlık durumları ile birlikte değerlendirilmelidir. Teşhis ve tedavi aşamasında; tam dişlilikten tam dişsizliğe doğru sırasıyla şöyle bir protetik sistem uygulanır. Birkaç diş eksikliğinde sabit protezden; hareketli bölümlü proteze( tek çene), hareketli bölümlü protez (iki çene), tam protez ve/veya hareketli bölümlü protez, alt ve üst tam protez şeklinde bir tedavi skalası vardır.
Effects Of Remover Techniques On Stress Distribution Of Implant Supported Fixed Partial Dentures And The Surroundıng Bone: A Finite Element Analysis
(2017) Özkır, Serhat Emre; Ünal, Server Mutluay; Çulhaoğlu, Ahmet Kürşad; Şeker, Emre
Background & Aims: Implant retained restorations may be retrieved due to many reasons. However, implant retained restorations have many components which may be damaged during removal. The aim of this study is to observe stress concentrations in the surrounding bone, the implant and its components, during retrieval of a three-unit implant-supported fixed partial denture using two different removal techniques. Materials and Methods: One three-dimensional digital model of an implant-supported three-unit restoration was constructed. The implants’ dimensions were 3.7 mm x 10mm. A pull out force of 40 N was applied on a single support and on the connectors with a loop device. The stress values were calculated within the dental implant, abutment, abutment screw and surrounding bone. Results: The highest stress concentration was observed at the collar of the abutment during load on a single support (16.246 MPa). The stress concentrations at the cortical bone were lower than the stress concentration at implants, while the maximum stress concentration in bone structure was 1.175 MPa. The loop device technique was enabled to share the load through both implants and reduce the stress concentration levels (9.941 MPa). Conclusion: The pull-out force, did not show a great effect in bone structure. However, implant components were under higher stress and abutment screw was the weakest part of the system. During a crown removal, more attention is needed in order not to damage implant components rather than the bone.
Satisfaction After Restoring Aesthetics and Function in a Child with Amelogenesis Imperfecta: A Case Report
(2016) Özcan, Nihal; Almaz, Merve Erkman; Sönmez, Işıl Şaroğlu; Barış, Emre
Amelogenezis imperfekta (Aİ) süt ve daimi dentisyonda diş minesinin formasyonunu tahrip eden kalıtsal bir hastalıktır. Aİ'li hastaların tedavisi hem hekim hem de hasta açısından zorlu bir süreçtir. Bu olgu sunumunda Aİ tanısı konulan altı yaşında bir kız hastanın tedavi süreci sunulmaktadır. Tedavi planlamasında, hastanın yaşı göz önüne alınarak ve büyüme ve gelişimi etkilemekten kaçınmak amacıyla hastaya hareketli protezler yapılmasına karar verilmiştir. Konvansiyonel tam protezler yapılarak, vertikal boyut artırılmış, istenilen estetik ve fonksiyon kazanılmıştır. Ayrıca protetik tedaviden memnuniyet, bir anket yardımıyla değerlendirilmiştir. Hasta ve ebeveyn memnuniyetinin yüksek düzeyde olduğu tespit edilmiştir. Aİ'li hastalarda tedavi planlamasında; hastanın yaşı, sosyo-ekonomik durumu, hastalığın şiddeti ve tipi, planlama yapıldığı süreçteki intraoral durum ve en önemlisi hasta kooperasyonu gibi pek çok faktör rol oynamaktadır.
Kapanışı olmayan dişlerde; uzama, dönme, devrilme sıklığı ve temporomandibular düzensizlikler ile ilgili çalışma
(2017) Baran, İlgi Tosun; Nalçacı, Rana
Amaç: Bu çalışmanın amacı, kapanışı olmayan dişlerde uzama, dönme ve devrilme sıklığı ile oklüzal girişimler ve molar dişlerin uzaması ile temporomandibuler düzensizlikler (TMD) arasındaki ilişkinin belirlenmesidir.Gereç ve Yöntem: Çalışma grubu posterior diş kaybı ile başvuran191 hastadan oluşmuştur. Bu dişlerin (462 molar diş) uzama, dönme ve devrilme kayıtları incelendi. Diş kaybı ve TMD belirtileri saptandı. Bağımsız değişkenler karşılaştırılması için Ki-kare testi ve Fisher kesin olasılık testi kullanılmıştır. TMD için Pearson korelasyon yaygınlık parametreleri kullanıldı.Bulgular: 291 azı dişinde, uzama belirtisi gözlemlenmedi. 119 azı dişinde, hafif uzama, 52 azı dişinde, orta ve şiddetli uzama görüldü. 184 azı dişinde, dönme belirtisi görülmedi, 203 molar dişte, 150den daha az, 75 dişte ise 150 den fazla dönme tespit edildi. 274 dişte devrilme gözlenmezken, 108 dişte 150 den az devrilme ve 80 dişte ise 150 den fazla devrilme gözlemlendi. TMD ortalama skorları ile genç yaş grubu ve cinsiyet (kadın) istatistiksel olarak anlamlı olarak bulundu (Yaş: P < 0.05. Cinsiyet: P < 0.001).Sonuç: Azı dişlerinde dönme bulgusu daha çok maksillada iken, uzama ve devrilme bulgusu daha çok mandibulada saptanmıştır. TMD ve diş kaybı belirtileri arasında anlamlı sonuçlar bulunmuştur, ancak bu sonuçlar molar destek kaybının, TMD hazırlayıcı faktörleri arasında olduğunu desteklemektedir
Effect of Various Treatment Modalities on Surface Characteristics and Shear Bond Strengths of Polyetheretherketone-Based Core Materials
(WILEY, 2020) Culhaoglu, Ahmet Kursat; Ozkir, Serhat Emre; Sahin, Volkan; Yilmaz, Burak; Kilicarslan, Mehmet Ali
Purpose To investigate the effect of different surface treatments on the surface roughness (Ra), wettability, and shear bond strength of polyetheretherketone (PEEK) to composite resin. Materials and Methods One hundred ninety eight PEEK specimens were divided into six groups (n = 33). Specimen surfaces were treated with the following surface treatment modalities: silicoating (CoJet), acetone treatment, acid etching (H2SO4), airborne particle abrasion (Al2O3), laser irradiation (Yb:PL laser), and the nontreated surface serving as the control. Surface roughness was measured with an profilometer (n = 11) and a goniometer was used to measure the surface wettability through contact angle (theta)(n = 11). PEEK surfaces were veneered with a composite resin (n = 11). The specimens were then thermocycled for 10,000 cycles at 5 to 55 degrees C. Shear bond strengths between the PEEK and composite resin were measured with an universal test machine. One-way ANOVA was used to analyze the data. Tukey's post-hoc test was used to determine significant differences between groups (alpha = 0.05). Results Surface roughness and wettability of PEEK surfaces along with shear bond strength of PEEK to composite resin were influenced by the surface treatments. (p < 0.01) Highest mean Ra values were obtained for PEEK surfaces treated by laser irradiation (2.85 +/- 0.2 mu m) followed by airborne particle abrasion (2.26 +/- 0.33 mu m), whereas other surface treatment modalities provided similar Ra values, with the acid-etched PEEK surfaces having the lowest mean Ra values (0.35 +/- 0.14 mu m). Silicoating provided the most wettable PEEK surfaces (48.04 +/- 6.28o), followed by either acetone treatment (70.19 +/- 4.49o) or acid treatment (76.07 +/- 6.61o). Decreased wettability was observed for airborne particle abraded (84.83 +/- 4.56o) and laser-treated PEEK surfaces (103.06 +/- 4.88o). The highest mean shear bond strength values were observed for acid-etched PEEK surfaces (15.82 +/- 4.23 MPa) followed by laser irradiated (11.46 +/- 1.97 MPa), airborne particle abraded (10.81 +/- 3.06 MPa), and silicoated PEEK surfaces (8.07 +/- 2.54 MPa). Acetone-treated (5.98 +/- 1.54 MPa) and untreated PEEK surfaces (5.09 +/- 2.14 MPa) provided the lowest mean shear bond strengths. Conclusions The highest mean shear bond strengths were observed for acid-etched PEEK surfaces, followed by laser-irradiated, airborne particle abraded, and silicoated PEEK surfaces providing similar mean shear bond strengths. Since shear bond strengths higher than 10 MPa are considered acceptable, acid etching, laser irradiation, and airborne particle abrasion of PEEK surfaces may be considered viable surface treatment modalities for the PEEK material tested.
Stress Analysis of Prostheses Retained with Zygomatic Implants on Augmented and Non-Augmented Maxillary Sinus
(AMER SCIENTIFIC PUBLISHERS, 2020) Güngör, Hamiyet; Kaman, Süleyman; Özgül, Özkan; Önder, Ercüment Mustafa; Atil, Fethi; Tekin, Umut Saraçoğlu; Koçyiğit, İsmail Doruk
Zygomatic implants for toothless, atrophic posterior maxilla are effective treatment options and it is known that graft use has a positive effect on the zygomatic implant stability with this treatment option. The aim of this study was to evaluate the stress values and their distribution at zygomatic implant-supported prosthetic infrastructure in augmented and non-augmented models. In this study, the three-dimensional finite element method was used and 2 zygomatic implants (47.5 x 4.0 mm), 2 conventional implants (13 x 3.75 mm) and atrophic maxilla with augmented and non-augmented maxillary sinus with prosthetic infrastructure, were modelled. A vertical load of 150 N was applied onto the maxillary model at 4 different regions (#9, #12, #14 and #15). The von Mises stress, which is produced as a result of loading of zygomatic implants and prosthetic infrastructure has been evaluated in augmented and non-augmented models. The highest von Mises stress value for the prosthetic infrastructure was determined in the non-augmented model as a result of the loading to region #9 (MPa 222,886). Consequently, grafting procedures will increase bone support and reduce stresses in the prosthetic substructure, especially in posterior loads in the maxilla with low bone density.
Different Restorative Systems In Non Carious Cervical Lesions
(ANNALS DENTAL SPECIALTY, 2020) Turkoglu, Ozge; Baglar, Serdar; Bulut, Ali Can
Background: Six different restorative systems were applied in non-carious cervical lesions (NCCLs). They demonstrated acceptable clinical performances, except for retention rates of Beautiful II, Beautiful Flow Plus F00, and Dyract XP restorations, after 12th month. Objective: The aim of this one-blind clinical trial was to evaluate and compare the clinical performance of six different restorative systems for restoring NCCLs. Methods: A total of 300 restorations (n=50) were placed in 33 patients who ranged in age between 35 and 85 years and of both genders, by a single operator. Each group was restored by different restorative systems: Single Bond-Universal & Filtek Ultimate and Filtek Ultimate Flow (3M ESPE); FLBondII-Beautifil II and Beautifil Flow Plus F00 (Shofu); Prime Bond NT-Dyract XP and Dyract Flowable (Dentsply) according to manufacturers' instructions. Evaluations were performed at baseline (1 week after placement) and 3rd, 6th, 9th, and 12th months using modified US Public Health Service criteria (recall rate 100%). The survival rates were analyzed with Kaplan-Meier and the Log-Rank tests and other categories analyzed with the Kruskal Wallis test at a significance level of 5% (p<0.05). Results: After 12 months, this study showed that while nanocomposite, flowable nanocomposite, and flowable compomer restorations demonstrated acceptable clinical performance and survival rate in noncarious cervical lesions. Giomer, flowable giomer, and compomer restorations were not successfully using the retention rate. Conclusions: In this study Beautifil II, Beautifil Flow Plus F00, and Dyract XP restorations performed fewer survival rates than other groups, although they showed similar clinical quality to other groups in other categories.
Evaluation of the repair capacities and color stabilities of a resin nanoceramic and hybrid CAD/CAM blocks
(KOREAN ACAD PROSTHODONTICS, 2020) Bahadir, Hasibe Sevilay; Bayraktar, Yusuf
PURPOSE. This study evaluated the color stabilities of two computer-aided design and computer-aided manufacturing (CAD/CAM) blocks and a nanofill composite resin and the microtensile bond strength (mu TBS) between the materials. MATERIALS AND METHODS. Twelve specimens of 4 mm height were prepared for both Lava Ultimate (L) and Vita Enamic (E) CAD/CAM blocks. Half of the specimens were thermocycled (10,000 cycle, 5 degrees to 55 degrees C) for each material. Both thermocycled and non-thermocycled specimens were surface treated with one of the three different methods (Er,Cr:YSGG laser, bur, or control). For each surface treatment group, one of the thermocycled and one of non-thermocycled specimens were restored using silane (Ceramic Primer II), universal adhesive (Single Bond Universal), and nanofill composite resin of 4 mm height (Filtek Ultimate). The other specimens were restored with the same procedure without using silane. For each group, 1 x 1 x 8 mm bar specimens were prepared using a microcutting device. Bar specimens were thermocycled (10,000cycle, 5 degrees to 55 degrees C) and microtensile tests were performed. Staining of the materials in coffee solution was also compared using a spectrophotometer. Data were analyzed using one-way ANOVA, t-test and post-hoc Scheffe tests. RESULTS. mu TBS were found similar between the thermocycled and non-thermocycled groups (P>.05). The highest mu TBS (20.818 MPa) was found in the non-thermocycled, bur-ground, silane-applied E group. Silane increased mu TBS at some E groups (P<.05). Composite resin specimens showed more staining than CAD/CAM blocks (P<.05). CONCLUSION. CAD/CAM blocks can be repaired with composite resins after proper surface treattilents. Using silane is recommended in repair process. Color differences may be shown between CAD/CAM blocks and the nanofill composite after a certain time period.
Effect of storage time on mechanical properties of extended-pour irreversible hydrocolloid impression materials
(MOSBY-ELSEVIER, 2020) Sahin, Volkan; Jodati, Hossein; Evis, Zafer
Statement of problem. Recent commercial extended-pour irreversible hydrocolloid impression materials (EPIHIMs) claim to maintain dimensional stability up to 120 hours. However, data regarding their mechanical properties and performance after 120 hours of storage are lacking. Purpose. The purpose of this in vitro study was to test the elastic recovery, strain in compression, and tear strength properties of 5 commercially available EPIHIMs, immediately after preparation and after 120 hours of storage under specific storage conditions. Material and methods. A total of 150 specimens were prepared in accordance with the ISO 21563:2013 standard from 5 commercially available EPIHIMs (Blueprint Xcreme, Kromopan, Alginmax, Hydrogum 5, and Alginelle). The specimens were subjected to elastic recovery, strain in compression, and tear strength tests immediately after specimen preparation (n=5) and after 120 hours of storage inside clear plastic zipper bags held at 23 degrees C (n=5). Data were analyzed with a multivariate analysis of variance (MANOVA) test for brand and duration parameters. Normality of data was analyzed with the Shapiro-Wilk test. The Duncan test or Games-Howell test was used for multiple comparisons (alpha=.05). Results. Elastic recovery and strain in compression values of the EPIHIMs tested were affected by brand and duration parameters (P<.001). Tear strength values of the EPIHIMs tested were affected by brand (P<.001); however, they were not affected by duration (P>.05). Data distribution was normal except for Alginmax in terms of the elastic recovery values and Blueprint Xcreme in terms of the strain in compression values (P<.05). Significant interactions were present between brand and duration for the strain in compression and tear strength values of the EPIHIMs tested (P<.05). Statistically significant difference was not found among mean elastic recovery values of the tested EPIHIM brands (P<.001). Moreover, a statistically significant increase was present in elastic recovery values of the tested EPIHIMs after 120 hours of storage (P<.001). Statistically significant difference was not found among mean strain in compression values of the tested EPIHIM brands tested immediately after preparation (P>.05). However, 120 hours of storage led both to a statistically significant decrease in mean strain in compression values of the tested EPIHIMs (P<.001) except for Alginelle (P>.05) and a statistically significant difference among mean strain in compression values of the tested EPIHIM brands (P<.001). Storage time did not influence mean tear strength values of the EPIHIMs tested (P>.05). However, statistically significant differences were present among mean tear strength values of the tested EPIHIM brands tested immediately after preparation (P<.001) and after 120 hours of storage (P<.001). Conclusions. Despite variations in elastic recovery, strain in compression, and tear strength properties of the EPIHIMs tested, all the materials fulfilled the requirements to comply with the ISO 21563:2013 standard even after 120 hours of storage.
Endodontic management of a patient with dystrophic epidermolysis bullosa: A case report
(WILEY, 2020) Türkyılmaz, Ali; Bulut, Ali Can; Hancerlioğulları, Dilek
Epidermolysis bullosa is a congenital genetic disease that causes blistering and erosion of the skin and mucosa. The main known forms include simple, junction, dystrophic and mixed subtypes. This case report presents the endodontic management and 1-year follow-up of a 27-year-old female patient with epidermolysis bullosa who was referred to the Faculty of Dentistry, Kirikkale University, Turkey. An extraoral examination showed that the patient had multiple scars and blisters. The intraoral examination revealed ankyloglossia, microstomia, shallow buccal and vestibular sulci, enamel hypoplasia, gingival inflammation, mouth ulcers, symptomatic and asymptomatic deep caries, a tooth with an apical lesion and a tooth with pulpitis. The dental treatment was divided into four stages: (i) oral hygiene motivation and elimination of gingival bleeding, (ii) restorative and/or endodontic procedures, (iii) extractions and prosthetic treatments and (iv) recall appointments. A 1-year follow-up radiographic examination of the periapical status of the root canal treatments was clear.
Oral parafunctions, personality traits, anxiety and their association with signs and symptoms of temporomandibular disorders in the adolescents
(Makerere Univ, Fac Med, 2019) Atsu, Saadet Saglam; Guner, Sibel; Palulu, Nilgun; Bulut, Ali Can; Kurkcuoglu, Isin
Objectives: To investigate the association between oral parafunctions, personality traits, anxiety and signs and symptoms of temporomandibular disorders in the adolescents. Methods: Two hundred and seventy adolescents were examined clinically for the signs and symptoms of temporomandibular disorders. Participants completed questionnaires about demographic variables, medical history, symptoms of temporomandibular disorders, parafunctional oral habits, Minnesota Multibasic Personality Inventory, and Spielberger State-Trait Anxiety Inventory. Results: Logistic regression analyses revealed that bruxism was associated with joint tenderness (Odds ratio (OR)=6.38, p < 0.01), joint noises (OR=6.02, p < 0.01) and masticatory muscle tenderness (OR=4.19, p < 0.05) to palpation. State anxiety showed increased risk of joint tenderness (OR=2.47, p < 0.05) and muscle tenderness (OR=3.25, p < 0.05) to palpation. Conclusion: Within the limitations of this study, it was concluded that oral parafunctions, especially bruxism, state anxiety, depression and hysteria were associated with signs and symptoms of temporomandibular disorders in adolescents.
Fracture Resistance of Titanium, Zirconia, and Ceramic-Reinforced Polyetheretherketone Implant Abutments Supporting CAD/CAM Monolithic Lithium Disilicate Ceramic Crowns After Aging
(Quintessence Publishing Co Inc, 2019) Atsu, Saadet Saglam; Aksan, M. Emin; Bulut, Ali Can
Purpose: The purpose of this study was to compare the fracture resistances and the fracture types of titanium, zirconia, and ceramic-reinforced polyetheretherketone (PEEK) implant abutments supporting computer-aided design/computer-aided manufacturing (CAD/CAM) monolithic lithium disilicate ceramic crowns after in vitro dynamic loading and thermocycling aging. Materials and Methods: Three implant abutment (SKY Implant) groups-titanium (group Ti, control); zirconia with titanium base (group Zr); and ceramic-reinforced PEEK (BioHPP) with titanium base (group RPEEK); n = 12 each-were used. Thirty-six CAD/CAM monolithic lithium disilicate crowns (IPS e. max CAD) in the form of a maxillary central incisor were cemented with Panavia V5 on the abutments. The specimens were subjected to dynamic loading and thermocycling. Fracture resistances of the restorations were tested with a universal testing machine (0.5 mm/min), and their fracture patterns were analyzed. One-way analysis of variance (ANOVA) and Tukey post hoc test were used for statistical analyses (alpha = .05). Results: All samples survived after aging. The fracture strength values (mean +/- standard deviation) of the groups were as follows: group Ti, 787.8 +/- 120.9 N; group Zr, 623.9 +/- 97.4 N; and group RPEEK, 602.9 +/- 121 N. The fracture strengths were significantly higher in group Ti compared to groups Zr and RPEEK (P =.001). No significant difference was observed between groups Zr and RPEEK. Failures generally occurred due to fracture of the screw in group Ti, abutment and crown in group Zr, and crown in group RPEEK. Conclusion: Ceramic-reinforced PEEK abutments may be an alternative to zirconia abutments with a titanium base for single-implant restorations in the anterior region. However, there is need for further in vitro and clinical studies to evaluate the long-term performance of ceramic-reinforced PEEK abutments.
The effect of repetitive firings on the color of an alumina ceramic system with varying ceramic shade and thickness
(Wiley, 2019) Sahin, Volkan; Aydin, Hilal Gulgezen; Akyel, Alim; Uludag, Bulent C.
Objective The color of all-ceramic restorations is one of the main criteria to achieve esthetical success. Many factors such as ceramic thickness, condensation techniques, firing temperature, and numbers can affect the final color of restoration. The purpose of this study was to investigate the color changes in alumina-based ceramic system according to ceramic shade and thickness during the multiple firings. Materials and Methods Sixty disc-shaped specimens with two different veneering porcelain shades (A1 or A3), and with three different ceramic thicknesses (0.5, 1, or 1.5 mm), were fabricated from an alumina-based ceramic system. Multiple firings (3, 5, 7, or 9 firings) were performed, and color changes (Delta E-00) were determined using a spectrophotometer. Repeated-measures ANOVA were used to analyze the data. The Duncan test was used for multiple comparisons (alpha = .05). Results The L*a*b* values of the specimens were affected by the number of firings (3, 5, 7, or 9), veneering ceramic shades (A1 or A3) and veneering ceramic thicknesses (0.5, 1, or 1.5 mm). Significant interactions were present between the number of firings, veneering ceramic shade, and veneering ceramic thickness for L* (p < .001), a* (p < .001), and b* (p < .001) values. Conclusions No statistically significant color change was observed between 3rd and 9th firings. Clinical Significance Veneering ceramic shade, veneering ceramic thickness, and number of firings should be carefully considered to obtain an acceptable color match of the definitive restorations.
Semi-Supervised Method for Determining the Maxillary and Mandibular Boundaries on Panoramic Radiographs
(Ieee, 2018) Ulku, Berkay Kagan; Yetik, Imam Samil; Culhaoglu, Ahmet Kursad; Orhan, Kaan; Kilicarslan, Mehmet Ali
X-ray imaging plays an important role in the detection and diagnosis of dental disorders that can not be detected with the eye. Examination, evaluation and accurate diagnosis of panoramic radiography images used in anomaly detection is a process requiring serious experience and expertise. In order to simplify this process and to increase accuracy, some studies have been carried out on both the imaging techniques and the development of the computer aided diagnosis systems by transferring these images to the digital medium. One of these studies is segmentation of various structures in dental X-ray images. In this study, instead of using random masks as initial inputs, we developed a special mask identification method for each image and gave the mask which is the output of this method as initial input to the segmentation algorithm to obtain more suitable elliptical forms closer to the actual(ground truth) results and to the maxillary and mandibular structures.
Oral rehabilitation with implant-supported fixed dental prostheses of a patient with cleidocranial dysplasia
(Mosby-Elsevier, 2018) Atil, Fethi; Culhaoglu, Ahmet; Kocyigit, Ismail Doruk; Adisen, Zahit; Misirlioglu, Melda; Yilmaz, Burak
This clinical report describes the oral rehabilitation with implant-supported fixed dental prostheses in the maxilla and mandible of a patient with cleidocranial dysplasia. Cone-beam computed tomography and a tilted implant protocol in the mandible helped to establish a conservative approach for bone preservation, prevent surgical complications, enable proper implant positioning to avoid anatomic structures, and support the fixed dental prostheses.
Influence of Cantilever Extension and Crown-to-Implant Ratio in Posterior Maxilla: A Finite Element Analysis
(Amer Scientific Publishers, 2018) Gungor, Hamiyet; Baran, Ilgi; Karaagaclioglu, Lale
This study aimed to evaluate the effect of increased cantilever extension length and crown-to-implant ratio on stress distributions, both in peri-implant bone and implant structure under oblique loads, using three-dimensional finite element analysis method. Six three-dimensional models of an atrophic posterior maxilla were created with a solid implant (4.1 x 10 mm) placed in first maxillar premolar site. One implant supported two-unit fixed dental prostheses were modeled using three different cantilever extension lengths (5, 7 and 9 mm) and two different crown-to-implant ratio (1/1 and 1.5/1). An oblique load of 300 N was applied to each model. The minimum and maximum principal stresses and von Mises stresses were evaluated. The highest minimum principal stress value was 129.8 MPa in cortical bone and the highest von Mises stress value at the implant structure was 449.3 MPa. Regarding the simulation outcomes it can be concluded that increasing cantilever extension length and crown-to-implant ratio will also increase the stress distribution in peri-implant bone and implant structure. While crown-to-implant ratio has greater effect than cantilever extension length in the stress concentration in cortical bone, cantilever extension length is found to be more prominent stress factor for the implant structure.
The first step of patient-specific design calvarial implant: A quantitative analysis of fresh parietal bones
(Springer, 2018) Govsa, Figen; Celik, Servet; Turhan, Tuncer; Sahin, Volkan; Celik, Meral; Sahin, Korhan; Kazak, Zuhal
BackgroundAccurate knowledge of the fracture of cranial bone can provide insight into the prevention of skull fracture injuries and help aid the design of energy-absorbing head protection systems and safety helmets. When cranial bone needs to be removed or is lost, subsequent reconstruction of the defect is necessary to protect the underlying brain, or correct esthetic deformities, or both. Ideal reconstruction of defected bone is possible utilizing a biocompatible implant with a bone-like design individualized for the specific patient. The purpose of this study is to investigate the anatomical and mechanical characteristics of fresh frozen human parietal bones and determine compliance of polylactic acid-based personalized three-dimensional implants in terms of mechanical properties in order to replace such defective bones.MethodsParietal bone specimens were extracted from 19 fresh frozen cadavers. Morphological parameters of individual bone specimens were measured using Image J software. Three-point bend tests were performed to extract Young's modulus and tensile strength of the specimens from the measured force and displacement data by modeling the bone specimens as curved linear elastic beams. Also, three-point bend tests were performed to polylactic acid-based three-dimensional replicas mimicking geometry of the bone specimens in order to determine whether the material's Young's modulus and tensile strength properties comply with parietal bones.ResultsEntire fresh parietal specimens were observed to be comprised of a three-layered structure: external layers consisting of compact, high-density cortical bone and the central layer consisting of low-density, irregularly porous bone structure. Mean thickness of three-layered structure was 6.251.46mm. Mean Young's modulus and tensile strength of the specimens were 1.401.34GPa and 44.56 +/- 21.94MPa, respectively where no statistically significant differences among genders were detected (p>0.05). Mean Young's modulus and tensile strength of the polylactic acid-based three-dimensional implants mimicking geometry of the bone specimens were 1.8 +/- 0.7GPa and 72.8 +/- 2.5MPa, respectively.ConclusionsPolylactic acid-based three-dimensional implants can be considered as acceptable candidates for temporary replacement of parietal defects in terms of mechanical properties.Level of Evidence: Not ratable.
Effect of different framework materials of resin-bonded bridges on load to fracture values and stress distribution
(Wolters Kluwer Medknow Publications, 2018) Baran, Ilgi; Arslan, Merve; Gungor, Hamiyet
Purpose: The aim of this study was to compare in vitro fracture strengths (FSs) of metal- and fiber-reinforced frameworks of resin-bonded bridges and to evaluate stress distribution with finite element analysis (FEA). Materials and Methods: Totally 80 extracted maxillary central and maxillary canine teeth were used for in vitro part of this study as two groups; metal-reinforced framework (n = 20) [(metal-supported resin-bonded bridge (MR-RB)] and fiber-reinforced frameworks (n = 20) [fiber-reinforced resin-bonded bridge (FR-RB) were prepared for three unit resin-bonded bridges. All bridges were loaded from lateral pontic at 1 mm/min crosshead speed and fracture values were recorded. MannuWhitney U-test was used for statistical analysis, and fracture patterns were evaluated visually. FEA was carried out in the second part of the study, and stress distribution of MR-RB and FR-RB structures was analyzed using one of the models from in vitro specimens as main model. Results: The mean FSs of MR-RB and FR-RB were 637.47 151.91 N and 224.86 80.97 N, respectively. Fiber-reinforced specimens were found to distribute stress more homogeneous and connectors in each framework were the regions where stress concentrated mostly. Conclusion: In vitro FSs of MR-RB and the stress concentration of the point that the forces were applied were higher as compared to other parts of the restoration. Furthermore, in contrast to FR-RB specimens, retainer tooth fractures were observed in MR-RB specimens.
Surface roughness and adaptation of different materials to secure implant attachment housings
(Mosby-Elsevier, 2017) Ozkir, Serhat Emre; Yilmaz, Burak; Kurkcuoglu, Isin; Culhaoglu, Ahmet; Unal, Server Mutluay
Statement of problem. Various materials are available to secure implant attachment housings in overdentures. Surface roughness and the adaptation of these materials to the denture base and the housings may increase the microcracks and bacterial adhesion at the interfaces in the long term. The surface characteristics of the interface between the denture base orientation material and the attachment housing have not been extensively studied. Purpose. The purpose of this in vitro study was to evaluate the surface roughness and the adaptation of 5 different housing orientation materials to the housings and the denture base. Material and methods. Fifty-five poly(methyl methacrylate) (PMMA) specimens (15 mm in diameter and 4 mm in height) were prepared with a clearance inside to allow the insertion of over denture housings. Five different materials were used for housing orientation (Quick Up, Ufi Gel Hard, Tokuyama Rebase II Fast, Meliodent, and Paladent). The specimens were thermocycled 5000 times between 5 degrees C and 55 degrees C. The surface roughness (Ra values) of the specimens was measured with a noncontact profilometer. Scanning electron images were made in order to inspect the PMMA-orientation material-housing interfaces. The Kruskal-Wallis test was used to investigate the differences between the surface roughness values of the orientation materials, and the Iman-Conover test was used for pairwise comparisons (alpha=.05). Results. The surface roughness values significantly differed between Quick up and Ufi Gel orientation materials only, and Quick up had smaller surface roughness values than Ufi Gel (P=.009). Microcracks were observed among the groups only at the junction of the orientation material and the housing after thermocycling. Conclusions. Ufi Gel Hard showed the roughest surfaces around the overdenture attachment housings. The adaptation between the orientation material and the housing may deteriorate, and increased surface roughness and microcrack formation may be seen around the housings.

Güncel Gönderiler