Subutay Han Altintas

Evaluation of monomer leaching from a dual cured resin cement

PURPOSE An increasing number of inlay cavities is restored with tooth-colored materials, especially ceramics are cemented with resin cements. The comonomer TEGDMA and other monomers Bis-GMA and UDMA have been identified as the main compounds released from polymerized resin cements into aqueous media. The present investigation was conducted to clarify the leaching behavior of the monomers of dual polymerized resin cement. MATERIAL AND METHODS Ten freshly extracted caries and restoration free molar teeth were used in this study. Standardized Class I preparations were prepared in all teeth. Lithium disilicate based (IPS Empress Esthetic) ceramic inlays were cemented with dual polymerized resin cement (Variolink II). After cementation, specimens were stored in 75% ethanol solution. High-performance liquid chromatography (HPLC) was used to analyze the amounts of three monomers in the solution (after 10 min, 1 h, 24 h, 3, 7, 14, and 21 days). Two-way ANOVA and Tukey HSD tests were used to evaluate the results (p < 0.05). RESULTS There were statistically significant differences among the amounts of the monomers (p < 0.01) and also among time periods (p < 0.01). While the TEGDMA resulted in significantly higher amount than Bis-GMA and UDMA, there were no statistically significant differences between amounts of Bis-GMA, UDMA (p = 0.06). The cumulative amount of monomers was the highest after 21 days (p < 0.01). CONCLUSION In the case of resin cement, leaching of TEGDMA was the highest and the cumulative amount of leaching monomers from resin cement was influenced by the time.

Discoloration of provisional restorations after oral rinses.

Purpose: Oral rinses are widely used to promote periodontal health with provisional restorations during the interim period. The aim of this study was to compare the discoloration of provisional restoration materials with different oral rinses. Material and Methods: A total of 140 disc-shaped specimens (shade A2) (10 mm x 2 mm) were prepared from one PMMA-based (TemDent Classic®) and three different bis-acrylic-based (Protemp II®, Luxatemp® and Fill-In®) provisional restoration materials (n=7). The color values (L*, a*, and b*) of each specimen were measured before and after exposure with a colorimeter, and the color changes (∆E) were calculated according to the CIE L*a*b* system. The specimens were immersed in each of the 4 oral rinses (alcohol-containing mouthwash, chlorhexidine, benzydamine HCl, benzydamine HCl and chlorhexidine) twice a day for 2 minutes. After 2 minutes of immersion in the oral rinses, the specimens were immersed in artificial saliva. The specimens were exposed to the oral rinses and the artificial saliva for 3 weeks. Two-way ANOVA, the Bonferroni test and the paired sample t-test were used for statistical analyses (p<0.05). Results: Comparison of the discoloration from the oral rinses after immersion for three weeks revealed no significant differences (p>0.05). The lowest color change was observed in PMMA-based Temdent in all oral rinses (p<0.05). There were no significant differences between the bis-acryl composites after immersion in saliva or the mixture of benzydamine HCl and chlorhexidine and the alcohol-containing mouthwash for 3 weeks (p>0.05). After immersion in chlorhexidine, the color change values of Protemp II and Fill-in showed significant differences (p=0.018). Protemp II also showed less discoloration than the other bis-acryl composites, and this color change was statistically significant (p <0.05). For all oral rinses, the L* value decreased while b* values increased, and this color change was found to be statistically significant (p <0.05). A* values were found to be significantly higher with oral rinses (p<0.05), except Protemp II immersed in benzydamine HCl or alcohol-containing mouthwash. Conclusions: The type of the oral rinse did not affect the discoloration process. For long-term esthetic results, choosing MMA-based materials for provisional restorations appears to be more effective.

Evaluation of the radiopacity of luting cements by digital radiography.

PURPOSE The aim of this study was to evaluate the radiopacity of eight contemporary luting cements using direct digital radiography. MATERIALS AND METHODS Ten specimens, (5 mm diameter, 1 mm high) were prepared for each material tested (RelyX ARC, RelyX U100, RelyX Unicem, Nexus 2, Nexus 3, Metacem, Breeze, Adhesor zinc phosphate). The specimens were stored in a moist chamber at 37°C until completely set, then radiographed using a Kodak digital sensor and an aluminum step wedge with variable thicknesses (1 to 13 mm in 1-mm increments) used for reference. A Kodak 2100 intraoral X-ray unit was operated at 60 kV, 7 mA, and 0.20 seconds. According to international standards, the radiopacity of the specimens was compared with that of the aluminum step wedge using the equal-density area tool of the Kodak Dental Imaging software (ver. 6.7). Data were analyzed by ANOVA and Tukeys test. RESULTS Adhesor zinc phosphate cement showed the highest radiopacity of all materials and dentin. Breeze showed the lowest radiopacity (p < 0.05). No significant difference in radiopacity was observed between dentin and RelyX ARC, Nexus 2, or Metacem (p > 0.05). The radiopacities of Nexus 3 and RelyX Unicem were significantly higher than those of other resin cements and dentin (p < 0.05). CONCLUSIONS All materials showed radiopacity above the minimum recommended by the International Organization for Standardization and the American National Standards/American Dental Association. Breeze had less radiopacity than dentin.

HPLC analysis of HEMA released from two different adhesive systems.

OBJECTIVES The aim of this study was to evaluate in vitro elution of 2-Hydroxyethyl methacrylate (HEMA) from two different adhesive systems, used in two dual polymerized resin cements for bonding of ceramic restoration by high performance liquid chromatography (HPLC). METHODS Twenty freshly extracted caries and restoration free molar teeth used in this study. Standardized Class I preparations were prepared in all teeth. A lithium disilicate based (IPS Empress Esthetic; Ivoclar) ceramic inlays were cemented with one of the dual polymerized resin cements (RelyX ARC; 3M ESPE or Nexus 2; Kerr) that have two different adhesive systems (Single Bond; 3M ESPE, Optibond Solo Plus; Kerr). After cementation, specimens were stored in 75% ethanol solution. HPLC was used to analyze the amount of HEMA in the solution (after 10 min, 1 h, 24 h, 3, 7, 14, and 21 days). Two-way analysis of variance and Tukey HSD tests were used to evaluate the results (p < 0.05). RESULTS There were statistically significant differences between adhesive systems according to the amount of released HEMA (p < 0.01) and also among time periods (p < 0.01). The amount of HEMA eluted from Optibond Solo Plus was significantly higher than Single Bond. The total amount of monomers was the highest after 21 days (p < 0.01). CONCLUSIONS In the case of adhesive systems, Optibond Solo Plus showed the highest amount of HEMA. The amount of HEMA eluted from adhesive systems influenced by the time.

Six-Year Survival of a Mini Dental Implant-Retained Overdenture in a Child with Ectodermal Dysplasia

Patients with ectodermal dysplasia (ED) experience several problems caused by abnormal development and functioning of the head and neck region. In addition to developmental nasal cartilage abnormalities and absence of sweat glands, hair, and eyebrows, edentulism or developmental disorders of teeth (cone-shaped teeth) are commonly observed in these types of patients. ED is also characterized by underdeveloped alveolar ridges, a decreased occlusal vertical dimension, reduced salivary secretion, and dry oral mucosa, which make prosthetic rehabilitation difficult. Few studies of intraosseous dental implant-retained prostheses have described adverse effects on craniofacial growth and esthetic and functional disadvantages, while some researchers have described the advantages of this treatment option as an alternative option in these cases. Due to the associated alveolar bone deficiency, dental mini-implant therapy may be a treatment option for these patients; however, there are isolated cases in the literature regarding the rehabilitation of ED patients with mini-implant-supported overdentures. This clinical report describes the rehabilitation of a 6-year-old child with ED using a maxillary removable partial prosthesis and a mini-implant-retained mandibular overdenture. The clinical and radiographic findings of this prosthetic rehabilitation during the 6-year follow-up are also presented.

Oral Rehabilitation with Implant-Retained Overdenture in a Patient with Down Syndrome.

Down syndrome, known as trisomy 21, is the most common chromosomal disorder. The disorder affects mental and systemic development as well as oral structure, including dental anomalies, high susceptibility of periodontal disease, and poor quality of alveolar bone. This report presents a case of dental rehabilitation by means of dental implants of a patient with Down syndrome. Two titanium dental implants were placed in the maxilla, and three titanium dental implants were installed in the mandible. One implant was lost during the osseointegration period. The prosthetic rehabilitation was performed with implant-retained maxillary and mandibular overdentures with the Locator attachment system. After a 2-year follow-up period, the patient was doing well, and all implants were clinically stable with no signs of bone loss or inflammation. The present study emphasizes that implant-retained overdentures with Locator attachment system could be a therapeutic option even for patients with Down syndrome. This therapy prevents crestal bone loss around the implants, improves functional and esthetic outcomes, and provides optimum oral hygiene for patients with mild mental impairment. Careful patient selection and education of patients and caregivers are essential considerations for a successful and safe treatment with dental implants in Down syndrome patients.

Evaluation of residual monomer release and toxicity of self-adhesive resin cements

The aim of this study was to evaluate the amount of leached residual monomers from self-adhesive resin cements and evaluate their toxicity in-vitro. A total of 60 disk-shaped specimens (5 mm in diameter and 0.5 mm in thickness) were prepared from each cement (RelyX U200, SpeedCEM, G-Cem) (n=20). Specimens were immersed in artificial saliva and the amount of released monomers [urethane dimethacrylate (UDMA) and triethyleneglycol dimethacrylate (TEGDMA)] was identified. Then, the cytotoxicity and genotoxicity effect on cells were evaluated using the defined amounts of released monomers from cements. The highest monomer release was detected in G-Cem (p<0.05). The highest cytotoxicity value was identified from SpeedCEM (p<0.01) and the highest genotoxicity values were calculated from RelyX U200 (p<0.05). Released UDMA and TEGDMA from self-adhesive resin cements induced cytotoxicity and genotoxicity effect on cells.

Is a Fixed Hybrid Prosthesis with Distal Cantilever Appropriate for Maxillofacial Defects? A Report of Two Patients.

The most important objectives in restoring the maxillofacial patient are the restoration of function and psychological improvement through esthetics. Acquired maxillary and mandibular defects due to significant trauma or surgery represent a major challenge for the clinician and patient. Dental implant-retained prostheses represent a well-documented and reliable treatment option and can also help patients with maxillofacial defects by eliminating denture instability and improving function. Full-arch fixed dental hybrid prostheses provide functional and psychological advantages and also reduce the load on vulnerable soft and hard tissues in the reconstruction area. Two clinical reports are presented describing the prosthetic rehabilitation using dental implant-supported fixed hybrid prostheses with clinical and radiographic follow-up of 3 years.

Oral bifosfonat tedavisi görmüş olan bir hastanın dental implant destekli protez ile rehabilitasyonu: Olgu sunumu

Bifosfonatlar kemik metabolizmasinda osteoklastik inhibitor etkileri nedeniyle bircok kemik ile ilgili hastalikta yaygin olarak kullanilmaktadir. Son yillarda intravenoz (IV) ve oral yolla alinan bifosfonatlarin, ciddi bir yan etkisi olan bifosfonata bagli cenelerde gorulen osteonekroz (BRONJ) hakkinda bir cok vaka rapor edilmistir. BRONJ olusturma riski yuksek olmasi nedeniyle IV bifosfonat kullanimi, dental implant uygulamalarinda kesin kontraendikasyon oldugu bildirilmistir. Ancak oral bifosfonat kullanan hastalarda dental implant yapilmasi ile ilgili oneriler sinirli verilere dayanmaktadir. Bu olgu raporunda, osteoporoz nedeniyle 3 yil bifosfonat tedavisi gormus olan hastanin dental implant destekli protez ile rehabilitasyonu sunulmustur.