FRACTURE RESISTANCE UNDER CYCLIC LOADING OF LITHIUM DISILICATE VONLAYS VERSUS ROSETTA VONLAYS RESTORING PREMOLARS (IN VITRO STUDY): مقاومة الكسر للقشور السطحية الخزفية المرممة للضواحك تحت تحميل دوري والمصنعة من الليثيوم ديسليكات مقابل القشور السطحية الخزفية المصنعة من الروزيتا: دراسة معملية

The aim of the study was to assess fracture resistance under cyclic loading of Rosetta®SM CAD vs. IPS e.max CAD (control) vonlays restoring maxillary premolars. According to the sample size calculation, a total of 20 samples will be selected and then divided into two equal groups; 10 sample each based on the material type: Group (A): Ten vonlays (n=10) manufactured from IPS e. max CAD blocks (control). Group ( B): Ten vonlays (n=10) manufactured from Rosetta®SM CAD blocks (intervention). A natural tooth presenting an upper first premolar was prepared in accordance with the ceramic onlay restorations preparation guidelines with an occlusal box with half of the bucco-lingual distance and a 2 mm depth from the cusp tip to pulpal floor, gingival seat with 1 mm depth from pulpal floor, occlusal reduction of 2 mm of the functional cusp with extending the preparation at the palatal surface by 2 mm in the cervical direction, occlusal reduction of 1.5 mm of non-functional cusp and 12º divergence angle. The preparation was then extended to the labial surface, with a 0.5 mm chamfer finish line. All line angles were finally rounded, and all margins were finished. For duplication of the natural tooth; the epoxy dies were constructed. Base and catalyst of the epoxy resin material were mixed as instructed by the manufacturer at a rate of 200r/min and then was poured into the silicon mould under vibration to eliminate any air voids, then was allowed to set completely following the manufacturer instructions for 24 hours, this procedure was repeated 20 times for creating 20 epoxy resin dies which replicating the prepared natural tooth. The die was then scanned by optical scanning using Medit i500 oral scanner. Milling of Vonlays was achieved using Sirona MCX5 milling machine using IPS e. max CAD blocks and Rosetta SM CAD blocks: 10 IPS e.max CAD blocks with block size C14 and 10 Rosetta®SM CAD blocks with block size C14 were used. Vonlays were then seated on their corresponding dies and cemented with dual cured self-adhesive resin cement (Variolink, Ivoclar Vivadent). Cementation procedures were performed by keeping each sample under a constant pressure of 5Kg using a custom designed cementation device for standardization the applied load during cementation process. All samples were mechanically aged (cyclic loading) to simulate 6 months of clinical use. Following that, all samples were subjected to fracture resistance testing under a compressive load to the center of their long axis using computer controlled universal testing machine with a load cell of 5 Kilo newton (K N) with a computer software used for data recording (Instron® Bluehill Lite Software). The mean values ± SDs values for e.max group were (502.39 ±102.89 N) with minimum value (338.16 N) and maximum value (721.29 N). The mean values ± SDs values. Rosetta group were (468.76 ± 67.54 N) with minimum value (367.11 N) and maximum value (648.48 N). Failure modes were determined under stereomicroscope and classified into repairable and catastrophic in both groups and showed that 60% of e.max group exhibited repairable failure while 40% of specimens showed catastrophic failure while in Rosetta group, 90% of the specimens exhibited repairable failure. Only 10% displayed catastrophic failure. Then a fractured part within each group was examined under scanning electron microscope (SEM) to reveal and compare their microstructure.

Estimation of Maxillary Anterior Teeth Width with Golden Proportion in Undergraduate Students

Aim: To estimate the frequency of coinciding width of maxillary front teeth and golden proportion ratio in undergraduate students. Study design: Descriptive Cross Sectional Place and Duration of Study: Department of Prosthodontics, Liaquat Medical University Hospital from June 2019 to January2020. Methodology: Total numbers of 96 students with maxillary anterior teeth were selected in this study. Appropriate size of upper maxillary impression of maxillary arch was made using alginate impression material with manufacturer prescribed instructions. The cast was retrieved between one and three hours of pouring. Digital caliper was used to measure for the spaces in the. The final recordings were entered in proforma. The data was analyzed by SPSS version-20. Results: Among the participants 65% were males and 35% females. The mean age of the participants was 21.02±1.88 years. Rate of coinciding was significantly high in 18 to 20 years of age (p=0.032).Coinciding width of maxillary anterior teeth and golden proportion ratio was significantly high in 1st year student (p=0.038) Conclusion: It was concluded that esthetics in dentistry cannot be justified mathematically and individuals should not be standardized. Whereas the dentists should follow few fundamental guidelines in the planning for esthetic treatment, it should be acknowledged that esthetics alters from person to person. That’s why it is important to consider the dento-facial specificities of every person and the inconstant natural tooth proportion during restoration or replacement of the maxillary front teeth.

Evidence Based Decision Making: A Review

In today’s era, many of the decisions are based upon gut feeling, intuition, or instinct rather than relied on actual scientific data and facts. It’s important and essential to do the needful based on facts and not feelings for the best possible outcomes. Evidence based decision making in the field of healthcare describes the integration of basic rules of evidence as they evolve into implementation in daily practices. In dentistry, the principles of evidence-based decision making as well as a very common clinical dilemma to make a decision on whether to save and preserve the natural tooth or to extract and replace it with an implant or any sort of prosthesis is often experienced by a clinician easily. The need of evidence plays a very important role in making decisions. It helps provide a better outcome which will result in fewer casualties.

Maintenance of diastema with a loop connector fixed partial denture: A Case Report

The replacement of a single maxillary central incisor is a unique prosthodontic challenge from esthetic as well as a functional point of view. Loss of anterior teeth with existing natural diastema presents problems such as increased mesiodistal space available for pontic which makes it very difficult to give conventional fixed prosthesis with rigid connector and wider pontics can be very unesthetic to look in the esthetic zone. This clinical situation is a major challenge for a prosthodontist; leaves him in a dilemma whether to close the space or to maintain it in a final fixed prosthesis simulating the natural tooth appearance. If implant-supported prosthesis is not possible fixed partial denture along with loop connector is the best solution to maintain the existing diastema and esthetics. This article presents a case report where fixed partial denture along with loop connector was used to achieve esthetic rehabilitation in maxillary anterior region maintaining natural existing diastema.

Peri-implant soft tissue au gmentation with connective tissue graft using „Two stage“ technique

Soft tissue augmentation using autogenous gingival grafts is a procedure often used in implantology and periodontal surgery. The technique of connective tissue grafting refers to the placement of connective tissue under a flap of partial thickness, which aims to induce the formation of keratinized tissue. It is indicated for partially or totally edentulous patients to increase the areas with the absence or reduction of the height of the keratinized tissue, as well as to increase the volume of soft tissue. The structural differences between the implant / bone tissue interface and the natural tooth / bone tissue make dental implants more susceptible to the development of inflammatory processes and bone loss. For these reasons, the intangibility of the seal around the implants is one of the primary objectives in its success over a long period of time. The function of the peri–implant seal is to “maintain internal homeostasis in response to external environmental challenges.”

CU-SIL DENTURE- AN ALTERNATIVE APPROACH TO PRESERVELONE STANDING REMAINING NATURAL TEETH: A CLINICAL CASE REPORT

Cu-sil dentures are a newer type of transitional denture. Cu-sil is the most straightforward and gentle removable partial denture available. Its a tissue-bearing acrylic denture with a soft elastomeric seal that holds the natural tooths neck in place, keeping food and fluids out while cushioning and splinting each natural tooth from the hard acrylic denture base.Cu-sil dentures are made to preserve the alveolar bone by preserving the remaining natural teeth. This case report demonstrates an alternative method for fabricating Cu-sillike dentures.

Anterior fracture tooth management using richmond crown-A case report

Maxillary central incisor is the most commonly affected tooth during trauma followed by maxillary lateral incisor and mandibular incisors. Trauma to the anterior tooth requires urgent care because of the essentiality of preserving the natural tooth. When a complicated crown a fracture takes place, it necessitates endodontic treatment and restoration of a fractured crown segment with post in the canal. This case report describes a patient with a broken central incisor and treated with a Richmond crown.

A Chitosan–Agarose Polysaccharide-Based Hydrogel for Biomimetic Remineralization of Dental Enamel

Developing multifunctional systems for the biomimetic remineralization of human enamel is a challenging task, since hydroxyapatite (HAP) rod structures of tooth enamel are difficult to replicate artificially. The paper presents the first report on the simultaneous use of chitosan (CS) and agarose (A) in a biopolymer-based hydrogel for the biomimetic remineralization of an acid-etched native enamel surface during 4–10-day immersion in artificial saliva with or without (control group) fluoride. Scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, Fourier transform infrared and Raman spectroscopies, X-ray diffraction, and microhardness tests were applied to investigate the properties of the acid-etched and remineralized dental enamel layers under A and CS-A hydrogels. The results show that all biomimetic epitaxial reconstructed layers consist mostly of a similar hierarchical HAP structure to the native enamel from nano- to microscale. An analogous Ca/P ratio (1.64) to natural tooth enamel and microhardness recovery of 77.4% of the enamel-like layer are obtained by a 7-day remineralization process in artificial saliva under CS-A hydrogels. The CS component reduced carbonation and moderated the formation of HAP nanorods in addition to providing an extracellular matrix to support growing enamel-like structures. Such activity lacked in samples exposed to A-hydrogel only. These data suggest the potential of the CS-A hydrogel in guiding the formation of hard tissues as dental enamel.