Journal of Istanbul University Faculty of Dentistry最新文献

The etiology of marginal bone loss around osseointegrated implants is primarily based on the biomechanical and/or microbial factors. If stresses and strains around dental implants under functional loading conditions are expected to exceed the physiologic tolerance thresholds of the alveolar bone, the fixed hybrid prosthesis might be a more reliable treatment of choice instead of fixed metal ceramic restorations. The purpose of this article is to report the 1-year follow-up of the periodontal and prosthetic rehabilitation of a patient who has presented with symptoms of peri-implantitis due to incorrectly planned implant supported fixed metal ceramic bridge which was later replaced with screw-retained hybrid prosthesis following the treatment of peri-implant defects. Treatment helped to maintain patient's self-confidence and comfort, as well as favorable masticatory function. Rehabilitation with screw retained hybrid prosthesis is an ideal treatment of choice for maxillomandibular skeletal discrepancies.

This case report presents the mandibular incisor extraction treatment of a patient with dental Class I malocclusion and lower crowding, in whom one mandibular incisor extraction was selected as the treatment of choice to improve the dental occlusion. A 19-year-old male patient's chief complaint was the crowding of lower incisors. He had a straight profile with normal upper and lower lip projection. Upper and lower dental midlines were coincident with the facial midline. The patient had Class I molar and canine relationships on both sides. He had Class I skeletal relationship, low angle vertical pattern, and proclined upper and lower incisors. The treatment plan included the extraction of lower right central incisor to resolve the crowding. At the end of 16-month active fixed treatment, lower dental crowding was resolved. At the 5-year follow-up, the patient had a stable occlusion, with the results of the orthodontic treatment maintained.

Purpose: The aim of this study was to evaluate the stability during healing and before loading of implants placed at two different supracrestal levels according to their collar texture.

Materials and methods: This retrospective study included patients who received posterior implants with the same macro design. Implants with a machined collar were placed 0.3 mm above the crestal bone (M group), while those with a laser-microtextured collar were placed 1 mm above the crestal bone (L group). All implants healed in a single stage with healing abutments. Implant stability quotient (ISQ) values were determined using resonance frequency analysis immediately after implant placement during surgery and after 1, 4, 8, and 12 weeks after surgery. Other evaluated factors for stability included the implant diameter and length and the site of placement (maxilla or mandible).

Results: In total, 103 implants (47 L, 56 M) were evaluated. The median ISQ values at baseline and 1 week after placement were significantly higher for the M group than for the L group (p=0.006 and p=0.031, respectively). There were no differences at the subsequent observation points. The ISQ value was higher for wide-diameter than regular diameter (p=0.001) and mandibular implants than maxillary implants (p=0.001 at 0-8. weeks; p=0.012 at 12 weeks) at all observation points. When diameter data were neglected, the implant length did not influence the ISQ value at all observation points.

Conclusion: Our results suggest that submerging implant more inside bone may only influence primary stability. Moreover, the implant diameter and site of placement influence primary and secondary stability before loading, whereas the implant length does not when its diameter is not accounted for.

Purpose: The aim of this retrospective study is to determine the radiological features of keratocystic odontogenic tumors (KCOT) using cone-beam computed tomography (CBCT).

Materials and methods: CBCT images of 28 patients who had histopathologically-confirmed KCOT were retrospectively reviewed from the archives of the Department of Dentomaxillofacial Radiology, Gazi University Faculty of Dentistry. The location and size of KCOT, cortical expansion, cortical perforation, relation with the impacted teeth, and the impact on the mandibular canal were evaluated.

Results: The mean age of patients at initial diagnosis was 34.5 years. Patients with an impacted tooth were significantly younger than those without an impacted tooth (p<0.05). Among KCOTs, 21% were localized in the maxilla whereas 79% were found in the mandible. The lesions localized in the mandible were mostly found in the retromolar-ramus region. Of these patients, 93% had cortical expansion and 75% had bone perforation. Of the 22 mandibular lesions, 20 were in close proximity of the mandibular canal and 18 (90%) of these lesions had caused destruction in the mandibular canal.

Conclusion: KCOTs exhibit their aggressive nature in the jaw bone. CBCT is a useful radiological imaging method to examine the radiologic characteristics of KCOTs such as bone destruction and their spatial relations with the neighboring anatomic structures.

Purpose: This in vitro study compared the effect of five different techniques on the surface roughness of feldspathic porcelain.

Materials and methods: 100 feldspathic porcelain disk samples mounted in acrylic resin blocks were divided into five groups (n=20) according to type of surface treatment: I, hydrofluoric acid (HFA); II, Deglazed surface porcelain treated with Neodymium:yttrium- aluminum-garnet (Nd:YAG) laser; III, Deglazed porcelain surface treated with Erbium:yttrium-aluminum-garnet (Er:YAG) laser; IV, Glazed porcelain surface treated with Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, V; Glazed porcelain surface treated with Erbium:yttrium-aluminum-garnet (Er:YAG) laser. The surface roughness of porcelain was measured with a noncontact optical profilometer. For each porcelain sample, two readings were taken across the sample, before porcelain surface treatment (T1) and after porcelain surface treatment (T2). The roughness parameter analyzed was the average roughness (Ra). Statistical analysis was performed using Kolmogorov-Smirnov and Wilcoxon signed rank test.

Results: Mean Ra values for each group were as follows: I, 12.64±073; II, 11.91±0.74; III, 11.76±0.59; IV, 3.82±0.65; V, 2.77±0.57. For all porcelain groups, the lowest Ra values were observed in Group V. The highest Ra values were observed for Group I, with a significant difference with the other groups. Kolmogorov-Smirnov showed significant differences among groups (p<0.001).

Conclusion: Surface treatment of porcelain with HFA resulted in significantly higher Ra than laser groups. Both Er:YAG laser or Nd:YAG laser on the deglaze porcelain surface can be recommended as viable treatment alternatives to acid etching.

Purpose: The discoloration of acrylic resin denture bases may lead to significant esthetic problems. The aim of this in vitro study was to investigate the effects of frequently consumed drinks on the color changes of fresh and aged, heat-polymerized, conventional acrylic resin.

Materials and methods: Eighty-four, heat-polymerized acrylic resin specimens (4 mm x 5 mm x 30 mm) were fabricated. Half of the specimens were aged by thermal cycling (between 5°C and 55°C, 60-second dwell time, 3000 cycles). The specimens were stored at 37°C in different drinks as non-aged and aged subgroups including water (control group), black tea, green tea, sour cherry juice, coke and coffee (n=7). The discoloration of each specimen after 1 and 7 days storage in the drinks were measured by a colorimeter based on CIE Lab system. The data of colour differences (ΔE) were analyzed by ANOVA and Dunnet's tests.

Results: Thermal cycling and storage in water induced a slight color change. The highest ΔE values were observed in the aged groups, which was also noticeable for black tea and sour cherry juice after 7 days of storage (ΔE>1.5) (p<0.05). The ΔE values of all test groups were detected within the acceptable clinical limits (ΔE<3.5).

Conclusion: These results suggest that the color stability of denture base acrylic resins is influenced by ageing. Black tea, sour cherry juice and coke can cause significant discolorations on acrylic resin denture bases.

Abscess of the infratemporal fossa is a rare complication which can be difficult to diagnose. It occurs mostly due to dental infection, tooth extraction, fractures and/or infections involving the maxillary sinus. This condition can be life threatening if not dealt with immediately. The maxillofacial surgeon must be aware of the symptoms and clinical findings of the infection of the infratemporal fossa in order to initiate the treatment as soon as possible. In this case report, a patient with an infratemporal fossa infection presenting with an unusual symptom of inferior alveolar nerve involvement is presented.

Purpose: The purpose of this retrospective study was to compare the performance of cone-beam computed tomography (CBCT) and panoramic radiography in detecting the presence and location of maxillary sinus septa.

Materials and methods: This study included radiographic examination of 104 maxillary sinuses of 52 individuals (26 females, 50% and 26 males, 50%) whose panoramic radiographs and CBCT images were obtained for several dental causes which were examined by the consensus of four dentomaxillofacial radiologists. The posterior maxillary segments in proximity of maxillary sinus were classified as edentulous and dentate maxillary segments. The location of maxillary sinus septa was classified as primary septa and secondary septa according to the presence of maxillary tooth at the affected site. The maxillary sinus septa were divided into three categories (anterior, middle and posterior) according to its relation with posterior maxillary teeth. Data were statistically analyzed with chi-square and Fisher's exact tests.

Results: The septa were found in 23.1% and 29.8% of the maxillary sinuses on panoramic radiography and CBCT images, respectively. The majority of maxillary sinus septa were observed in dentate posterior maxillary segments on both panoramic (45.8%) radiography and CBCT (64.5%) images. Statistically significant differences (p<0.001) were found between panoramic radiography and CBCT images for presence, location and neighborhood with the posterior maxillary teeth of maxillary sinus septa.

Conclusion: The results of this study demonstrated the low reliability of panoramic radiography images in the detection of maxillary sinus septa. CBCT images can provide valuable information to the clinicians about the presence and location of maxillary sinus septa.

Fibrous dysplasia (FD) is a bone disorder in which fibrous tissue replaces normal bone. FD can be monostotic (10%-25%) or polyostotic (50-90%) and is typically diagnosed accidentally on radiographs. Craniofacial lesions are typically unilateral and are diagnosed by clinical assessment and radiographic evaluation. This report describes the case of a 50-yearold female patient who had presented with painless swelling of the right maxilla and was diagnosed with FD. Subsequent bone scintigraphy identified the lesion as monostotic. Based on the patient's age and the radiographic data, contour correction was performed. However, 1 year after surgery, the lesion regrew and the treatment was repeated.

Purpose: The aim of this study was to evaluate the effects of 4 mouth rinses on the color stability of two different resin composites.

Materials and methods: A2 shade sonic-activated bulk fill material SonicFill (Kerr) and conventional nanohybrid composite Filtek Z550 (3M ESPE) were used. Forty disc-shaped specimens (10 mm x 2 mm) were fabricated for both composites and finished using 400-grit SiC paper and polished. After polishing and immersing in distilled water for 24h all specimens were subjected to color measurements. The baseline color values (L*, a*, b*) of each specimen were measured with a colorimeter. Following baseline measurement each composite group was divided into 5 groups: Oral-B Pro Expert Clinic Line Alcoholfree (Oral-B) group, Listerine Tooth Defense Rinse (Listerine) group, Pharmol Zn Mouth rinse (Çözümilaç) group, Nilera Mouth rinse (Nilera) group and Distilled water (control) group. The specimens were incubated in mouth rinses (20 ml) at 37°C for 12 hours and subjected to color measurement. Two-way ANO VA was used for statistical analysis (p<0.05).

Results: SonicFill showed significantly higher discoloration when exposed to Oral-B Pro Expert Clinic Line Alcohol-free, Listerine Tooth Defense Rinse and Pharmol Zn Mouth rinse. The color differences of two resin composites were not statistically significant for distilled water and Nilera Mouth rinse.

Conclusion: Within the limits of this study it can be concluded that the SonicFill showed higher discoloration than nanohybrid resin composite Filtek Z550.