Oya Aktören

Dental Implant Systems

Among various dental materials and their successful applications, a dental implant is a good example of the integrated system of science and technology involved in multiple disciplines including surface chemistry and physics, biomechanics, from macro-scale to nano-scale manufacturing technologies and surface engineering. As many other dental materials and devices, there are crucial requirements taken upon on dental implants systems, since surface of dental implants is directly in contact with vital hard/soft tissue and is subjected to chemical as well as mechanical bio-environments. Such requirements should, at least, include biological compatibility, mechanical compatibility, and morphological compatibility to surrounding vital tissues. In this review, based on carefully selected about 500 published articles, these requirements plus MRI compatibility are firstly reviewed, followed by surface texturing methods in details. Normally dental implants are placed to lost tooth/teeth location(s) in adult patients whose skeleton and bony growth have already completed. However, there are some controversial issues for placing dental implants in growing patients. This point has been, in most of dental articles, overlooked. This review, therefore, throws a deliberate sight on this point. Concluding this review, we are proposing a novel implant system that integrates materials science and up-dated surface technology to improve dental implant systems exhibiting bio- and mechano-functionalities.

Fracture resistance of immature teeth filled with BioAggregate, mineral trioxide aggregate and calcium hydroxide

UNLABELLED Abstract -  Background: The aim of this in vitro study was to assess the long-term fracture resistance of human immature permanent teeth filled with BioAggregate (BA), mineral trioxide aggregate (MTA) and calcium hydroxide (CH). MATERIALS AND METHODS  The study consisted of single rooted premolar teeth with immature root formation extracted for orthodontic reasons. A total of 28 immature premolars with average root length of 10.7 mm and apical diameter of 3 mm were included in the study. The pulps were extirpated and the canals were prepared using an apical approach. The teeth were randomly assigned to four groups: Group I: DiaRoot(®) BA (DiaDent, Burnaby, BC, Canada), Group II: Angelus MTA (MTA-A; Angelus, Londrina, Brazil), Group III: ProRoot(®) MTA (MTA-PR; Dentsply, Tulsa, OK, USA), Group IV: CH (Sultan Chemists Inc., Englewood, NJ, USA). The teeth were placed in saline solution at 4°C for 1 year. The root of each tooth was then embedded in an acrylic resin block. All specimens were loaded at a crosshead speed of 1 mm min(-1) in an Instron testing machine and the peak loads up to fracture were recorded. Data were analysed statistically by Kruskal-Wallis and Mann-Whitney U-tests. RESULTS  Mean (±SD) failure loads (MPa) were: 37.69 ± 14.43 for BA group, 32.94 ± 8.15 for MTA-A group, 28.74 ± 9.49 for MTA-PR group and 23.18 ± 8.48 for CH group. The BA group exhibited the highest fracture resistance and the CH group showed the lowest resistance to fracture. Significant differences (P < 0.05) in fracture resistance were found between the DiaRoot-BA and CH groups, and also between the MTA-A and CH groups. CONCLUSION  Within the limitations of this study, data suggest that DiaRoot-BA-filled immature teeth demonstrate higher fracture resistance than other groups at 1 year. Considering the long-term risk of cervical root fracture associated with immature teeth, the use of DiaRoot-BA as a root canal filling material appears to be the most advantageous of the materials tested.

Enamel–Renal–Gingival syndrome, hypodontia, and a novel FAM20A mutation

Enamel–Renal–Gingival Syndrome, Hypodontia, and a Novel FAM20A Mutation Piranit Nik Kantaputra,* Chotika Bongkochwilawan, Massupa Kaewgahya, Atsushi Ohazama, Hulya Kayserili, Arzu Pinar Erdem, Oya Aktoren, and Yeliz Guven Center of Excellence in Medical Genetics Research, Chiang Mai University, Chiang Mai, Thailand Division of Pediatric Dentistry, Department of Orthodontics and Pediatric Dentistry, Chiang Mai University, Chiang Mai, Thailand Craniofacial Genetics Laboratory, Faculty of Dentistry, Chiang Mai University, Chiang Mai, Thailand Dentaland Clinic, Chiang Mai, Thailand Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan Medical Genetics Department, Istanbul Medical Faculty, Istanbul University, Istanbul, Turkey Department of Pedodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey

X-ray diffraction analysis of MTA-Plus, MTA-Angelus and DiaRoot BioAggregate

Objective: The purpose of this study was to investigate and compare the crystalline structures of recently released MTA Plus (MTA-P), MTA Angelus (MTA-A), DiaRoot BioAggregate (BA) by X-ray diffraction (XRD) analysis. Materials and Methods: Phase analysis was carried out on powder and set forms of tested materials. The powder specimens placed into sample holders that were packed with a glass slide and the set samples prepared according to the manufacturer′s instructions were placed into molds. The samples after being set for three days at 37°C and 100% humidity in an incubator were mounted onto the XRD machine and phase identification was accomplished using a search-match software program. Results: XRD findings indicated that major constituents of MTA-P were bismuth oxide, portlandite, dicalcium silicate and tricalcium silicate. The crystal structure of MTA-A were similar to those of MTA-P except for the absence of portlandite. Additionally, MTA-A had tricalcium aluminate differing from MTA-P. BA mainly differed from MTA-P and MTA-A by the radiopacifier (tantalum oxide-TO) in its composition. Conclusions: The majority of constituents of the tested materials have shown similarity except for the presence of tricalcium aluminate in MTA-A and the inclusion of TO in BA. In addition, set MTA-P showed a strong peak of portlandite.

Orodental findings of a family with lacrimo-auriculo-dento digital (LADD) syndrome

Lacrimo-auriculo-dento-digital (LADD) syndrome is an autosomal dominantly inherited disorder characterized mainly by hypoplasia/aplasia of lacrimal and salivary tracts, small cup-shaped and/or malformed ears, sensorineuronal or conductive hearing loss, abnormalities of the teeth, and variable anomalies of the hands and feet. In this case report, general and dentofacial features of 2 siblings and their father are described. Both siblings presented hypoplastic lacrimal puncta, cup-shaped/low-set ears with bilateral sensorineuronal hearing loss, broad first toes, and bilateral clinodactyly of the fifth toes. The 17-year-old female revealed mainly peg-shaped incisors, long thin-rooted teeth, malformed molars, microdontia, and enamel hypoplasia; and the 10-year-old male showed a short lingual frenulum, peg-shaped incisors, shallow cusps, agenesis of mandibular second premolars, and taurodontism. Father exhibited hypoplastic puncta, hypolacrimia, mild bilateral sensorineural hearing loss, taurodontism, and absence of some teeth. In conclusion, this case report of a family has demonstrated the various general and orofacial features encountered in LADD syndrome.

A novel c.1255G>T (p.D419Y) mutation in SH3BP2 gene causes cherubism in a Turkish family.

Cherubism (MIM no. 118400) is a rare autosomal dominant disorder characterized by bilateral multilocular lesions of the upper and lower jaws. The lesions usually manifest clinically during early childhood, progress until puberty, and regress in adulthood. SH3BP2 is the only gene currently known to be associated with cherubism. This study began with an 8-year-old boy who was referred owing to overgrowth of mandible. A panoramic radiograph revealed multilocular radiolucent lesions of the upper/lower jaws, suggestive of cherubism. Sequence analysis of SH3BP2 revealed a novel c.G1255T change in exon 9 of the gene where 80% of the disease-causing mutations were observed. We report here the clinical and molecular findings of a family with 3 affected members in two generations showing variable clinical expressivity with the regression of symptoms with advancing age and the lack of penetrance.

Craniodentofacial Manifestations In Hallermann-Streiff Syndrome

Abstract Hallermann-Streiff syndrome (HSS) is a rare congenital disorder characterized by significant craniofacial findings. Dyscephaly, microphthalmia, cataracts, hypotrichosis, cutaneous atrophy, thin pinched nose, and a typical bird-like face are the main features of the syndrome. Additional features of the syndrome include dental anomalies, micrognathia, skeletal defects, and short stature. What follows is a case report of a 10-year-old girl with HSS with special consideration on orodental findings. Clinical, radiographic, and cephalometric analysis revealed hypoplasia of the mandible, high arched palate, Class II malocclusion due to mandibular retrognathia, open bite, posterior crossbite, crowding, malformed teeth, and oligodontia. Magnetic resonance images (MRI) of the temporomandibular joints showed abnormal disks flattened with uniform thickness and deformed condyles bilaterally. Also discussed are the features of HSS with the differential diagnosis, and the dental management of the case is described.

Twins with hereditary sensory and autonomic neuropathy type IV with preserved periodontal sensation.

Turkish twin brothers affected with hereditary sensory and autonomic neuropathy type IV (HSAN IV) are reported. Their clinical findings were generally typical for HSAN IV. Interestingly they both had preserved periodontal sensation. Mutation analysis of the NTRK1 gene showed a homozygous c.2001C>T substitution in exon 15 in both twins. This base substitution is predicted to change a polar, positively charged amino acid arginine to the highly active amino acid cystein at position 654 (p.Arg654Cys). The parents were heterozygous for the mutation. This mutation has been reported previously in one Japanese and one Arab patients. The preserved periodontal sensation has not previously been reported in patients affected with HSAN IV. This preserved sensation in our patients might have been through Ruffini endings, the periodontal mechanoreceptors which have been reported to be present in TrkA knockout mice. Here we report the first twins affected with HSAN IV and the observation that periodontal sensation is not affected by mutation in NTRK1.

A biallelic ANTXR1 variant expands the anthrax toxin receptor associated phenotype to tooth agenesis

Tooth development is regulated by multiple genetic pathways, which ultimately drive the complex interactions between the oral epithelium and mesenchyme. Disruptions at any time point during this process may lead to failure of tooth development, also known as tooth agenesis (TA). TA is a common craniofacial abnormality in humans and represents the failure to develop one or more permanent teeth. Many genes and potentially subtle variants in these genes contribute to the TA phenotype. We report the clinical and genetic impact of a rare homozygous ANTXR1 variant (c.1312C>T), identified by whole exome sequencing (WES), in a consanguineous Turkish family with TA. Mutations in ANTXR1 have been associated with GAPO (growth retardation, alopecia, pseudoanodontia, and optic atrophy) syndrome and infantile hemangioma, however no clinical characteristics associated with these conditions were observed in our study family. We detected the expression of Antxr1 in oral and dental tissues of developing mouse embryos, further supporting a role for this gene in tooth development. Our findings implicate ANTXR1 as a candidate gene for isolated TA, suggest the involvement of specific hypomorphic alleles, and expand the previously known ANTXR1‐associated phenotypes.

A Complex Facial Trauma Case with Multiple Mandibular Fractures and Dentoalveolar Injuries.

The principles of management of mandibular fractures differ in children when compared to adults and depend on the specific age-related status of the growing mandible and the developing dentition. This paper presents a case report with a complex facial trauma affecting the mandibular body and condyle region and dentoalveolar complex. Clinical examination revealed soft tissue injuries, limited mouth opening, lateral deviation of the mandible, an avulsed incisor, a subluxated incisor, and a fractured crown. CBCT examination revealed a nondisplaced fracture and an oblique greenstick fracture of the mandibular body and unilateral fracture of the condyle. Closed reduction technique was chosen to manage fractures of the mandible. Favorable healing outcomes on multiple fractures of the mandible throughout the 6-year follow-up period proved the success of the conservative treatment. This case report is important since it presents a variety of pathological sequelae to trauma within one case.