Evaluation of trabecular bone changes according to the type of prosthesis in patients using bisphosphonates: a retrospective study

Abstract The objective of the study was to retrospectively compare the fractal size values calculated in the trabecular bone according to the type of complete removable denture, removable partial denture, and partial fixed prosthesis between patients using bisphosphonates and healthy patients, retrospectively. Panoramic radiographs of a total of 200 patients, (100 using bisphosphonates,100 control group), were taken from the right and left molar regions before and after treatment with 72 × 72 pixels. The fractal dimension (FD) was computed by using ImageJ Software using the box-counting method on the images obtained. There was an interaction effect between the trabecular bone change-patient group-the type of prosthesis used and the parameters of the area (p < 0.05). In patients using complete removable dentures and removable partial dentures in the maxilla and mandibula in the molar region, a greater decrease in FD values was observed in the control group than in the patient group using bisphosphonates. An increase in FD values over time was observed in the patient group using bisphosphonates with partial fixed maxillary and mandibular prostheses compared to the control group. Partial fixed prostheses should be preferred primarily instead of complete removable or removable partial dentures in patients using bisphosphonates to prevent osteonecrosis due to dental trauma

Influence of shade of adhesive resin cement on its polymerization shrinkage

Resin cements have the ability to bond to the tooth structure and to several indirect restorative materials and they are available in different transparency and shades. However, polymerization shrinkage remains to be a problem that leads to gap formation at the margins of restoration, and accordingly microleakage may occur. The purpose of this study was to investigate the influence of the shade of adhesive resin cement on its polymerization shrinkage. Five shades (Group 1: universal; Group 2: brown; Group 3: clear; Group 4: opaque white; Group 5: opaque yellow) of a dual-cure composite cement system (Clearfil Esthetic Cement, Kuraray, Tokyo, Japan) were studied with 10 specimens of each shade. Volumetric shrinkages of the composite cements of these five shades were evaluated using a video-imaging device (Acu-Vol; Bisco, Inc.) by measuring the volumes before and after polymerization. Different shades displayed different volumetric shrinkages. Group 5 (2.62%) and Group 2 (3.96%) displayed the lowest and highest shrinkage percentages, respectively, with their respective shrinkage values being significantly different from those of the other groups (p < 0.05). The obtained results indicate that the shade of resin cement does affect its degree of polymerization shrinkage

Tüm seramik sistemlerinde alt yapı malzemelerinin üst yapı malzemeleri ile olan ısıl uyumlarının karşılaştırılmalı olarak araştırılması

Doğal diş görünümünde ve işlevsel kuvvetler altında yapısal bütünlüğünü koruyabilen tüm seramik restorasyon üretilirken, mekanik dayanımı yüksek seramik alt yapı, ışığı geçirebilen üst yapı seramiği ile kaplanır. Farklı tabakalardan oluşan bu restorasyonun üretim aşamasında anlık (zamana bağlı) ve artık ısıl gerilmeler oluşur. Bu gerilmeler seramikte mikroçatlaklara ve kaplama seramiğinin kırılıp dökülmesine neden olabilir. Bu da klinik başarısızlığa neden olur. Bu çalışmada, altı farklı tüm seramik sisteminde alt yapı seramiği ile üst yapı seramiği arasındaki ısıl uyum karşılaştırmalı olarak araştırılmıştır. Bu amaçla, her bir seramik sisteminin alt yapı seramiğinden 10’ar adet, 0,5 mm çapında iki yüzü paralel levha seklinde yuvarlak örnekler hazırlanmıştır. Örnekler tavlandıktan sonra profil ölçümleri yapılmış (AMBIOS XP-2 high resolution surface profiler) daha sonra birinci dentin, ikinci dentin ve glazür pişirimi yapılmıştır. Her bir pişirim sonrası profil ölçümleri tekrarlanmıştır. Örneklerdeki çarpılma miktarları ölçülmüştür. Elde edilen bulgular istatistiksel olarak değerlendirilmiştir. Grupların son çarpılma miktarı karşılaştırıldığında en az çarpılma Lava Zirconia / Lava Ceram gurubunda görülmüştür (1,4221385 μm). IPS e.max Press / IPS e.max Ceram grubu 2,710707 μm ‘lik fark miktarı ile en az çarpılma gösteren ikinci grup olmuştur. En fazla çarpılma değeri 6,921777 μm olarak Turkom Cera / Vita VM7 gurubunda görülmüştür. Çalışmanın sonlu elemanlar çözümleme aşamasında, fırınlama sırasında zaman bağlı oluşan ve artık ısıl gerilimlerin dağılımları araştırıldı. Bu amaçla; anterior tek kron, anterior 3 üye ve posterior 4 üye köprü modeli hazırlandı. Malzemelerin yüksek sıcaklıktaki mekanik özellikleri hesaplandı ve elastik sonlu elemanlar çözümlemesi yürütüldü. Oluşan çekme kuvvetlerinin 52-144 MPa arasında, artık çekme gerilmelerin de 7 – 29,2 MPa arasında değiştiği görüldü. Çekme gerilmelerinin en fazla ara yüzde, servikal basamaklarda ve tasarımın keskin köseli bölgelerinde biriktiği izlenmiştir. Bu çalışmada tabakalı tüm seramik sistemlerde altyapı ile üstyapı arasındaki ısıl uyum kavramı irdelenmiştir. Çalışmanın bulguları ışığında malzemelerin ısıl genleşme katsayıları farkının artık gerilmeleri arttırdığı görüldü ve bilimsel olarak ispatlandı. Kullanılan seramik sisteminin tabaka sayısının artmasının, artık ısıl gerilmeleri arttırdığı ve ısıl uyumu bozduğu bulunmuştur. Seramiklerde glazür pişiriminin artık gerilmeleri rahatlattığı bulundu. Seramik restorasyon tasarımı yapılırken keskin köse ve kenar oluşturmaktan kaçınılmalı ve sistemdeki tabaka sayısının artmasının artık gerilmelerin şiddetini arttıracağı göz önünde bulundurulmalıdır. Eğer tüm seramik sistemi oluşturan üyeler arasındaki ısıl genleşme katsayısı farkı fazla ise restorasyonun soğutma işlemi sırasında camsı dönüşüm sıcaklığı civarında soğutma hızının düşürülmesi ısıl uyumsuzluğun azalmasına katkıda bulunur

Midline Diastema Closure with Partial Laminate Veneers: A Case Report

This case report describes a treatment of big diastema with hybrid ceramic restorative material, using chairside CAD/CAM system with veneer technique

An overview of monolithic zirconia in dentistry

Zirconia restorations have been used successfully for years in dentistry owing to their biocompatibility and good mechanical properties. Because of their lack of translucency, zirconia cores are generally veneered with porcelain, which makes restorations weaker due to failure of the adhesion between the two materials. In recent years, all-ceramic zirconia restorations have been introduced in the dental sector with the intent to solve this problem. Besides the elimination of chipping, the reduced occlusal space requirement seems to be a clear advantage of monolithic zirconia restorations. However, scientific evidence is needed to recommend this relatively new application for clinical use. This mini-review discusses the current scientific literature on monolithic zirconia restorations. The results of in vitro studies suggested that monolithic zirconia may be the best choice for posterior fixed partial dentures in the presence of high occlusal loads and minimal occlusal restoration space. The results should be supported with much more in vitro and particularly in vivo studies to obtain a final conclusion

ENDOCROWN RESTORATION OF THE ENDODONTICALLY TREATED TEETH BY USING CAD/CAM: CASE SERIES

Aim: As a result of large coronal destruction in endodontically treated teeth, significant losses occur in the dentin tissue around the pulp and the need for prosthetic treatment occurs. In this case series, endocrown applications produced in a single session with CAD/CAM system are presented as an alternative to crown restoration traditionally applied to premolar and molar teeth with excessive crown destruction. Case Series: In first case, 38-years-old male patient number 25, 46-years-old female patient number 36 in our second case, 21-years-old female patient number 46 in our third case, 26-years-old male patient number 46 in our fourth case, and in the last case 52-years-old male patient tooth number 15 has been applied to root canal treatment. As a result of the clinical and radiological examinations of the patients, it was observed that there were no systemic diseases. Endocrown restoration was considered appropriate and recommended to patients with less dentin tissue. Firstly, teeth are prepared for endocrown restoration. Afterwards, the impressions were digitalized by scanning the jaws with an intraoral optical scanner (Cerec Omnicam, Dentsply Sirona, USA). The restorations were designed with the help of the CEREC 4.3 software (Dentsply Sirona, USA) and the milling process was carried out using the feldspathic ceramic block (Vita Mark II, Vita Zahnfabrik, Germany) in the same session by CEREC inLab MC XL (Dentsply Sirona, USA). Later, the restorations were glazed and cemented with dual polymerized resin cement (RelyX Ultimate, 3M ESPE, USA). Conclusion: Endocrown restorations are a minimally invasive, conservative treatment approach that provides mechanical adhesion to the pulp chamber and cavity walls with adhesive resin cement and allows the preservation of the remaining tooth structure. For this reason, it is a treatment option that can be preferred instead of post-core and crown application in teeth with root canal treatment

Does Surface Finishing Method Can Alter the Colour of Monolithic Zirconia Restoration?

Monolithic zirconia restorations offer superior mechanic properties and improve indication of non-metallic restorations. Monolithic restorations eliminate bonding and chipping problems mostly seen in zirconia restorations. However, optical properties are insufficient. Colouring or staining is offer possibility to mask the opaque view of restoration. Polishing and glazing are also surface treatment methods for monolithic zirconia