Fracture Localisation of Porcelain Veneers with Different Preparation Designs.

BACKGROUND: Porcelain veneers are permanent restorations that combine good aesthetic with functionality by minimal destructive techniques. AIM: This study aimed to investigate the influence of the preparation designs on the fracture localisation. MATERIAL AND METHODS: Three preparation designs of porcelain veneers fabricated by a method of laying on a fireproof abutment on maxillary central incisor were examined in this in vitro study-feather preparation, bevel preparation and incisal overlap - palatal chamfer. The samples from all three groups were loaded into a universal test machine-TRITECH WF 10056 until damage occurred on the porcelain veneer. Fracture localisation was classified as an incisal, gingival or combination. Data were analysed with statistical programs: STATISTICA 7.1; SPSS 17.0. RESULTS: In feather preparation, as a consequence of the mechanical force, the most common is the incisal localisation (66.7%), followed by the combined (33.3%), while the gingival fracture localisation is not registered. In bevel preparation, the most common fracture localisation is combined (53.6%), followed by incisal (35.7%) and subsequent gingival localisation (10.7%). In incisal overlap (palatal chamfer), combined and gingival localisation of the fracture is equally recorded in 14.3% of the samples, while the incisal is the most common localisation and is registered in 72.4%. CONCLUSION: During the study, a statistically significant dependence was found between the localisation of the occurred changes (incisal, gingival and combination) and the three different types of preparation.

Hydrofluoric Acid: Burns and Systemic Toxicity, Protective Measures, Immediate and Hospital Medical Treatment.

BACKGROUND: Hydrofluoric acid is a commonly used chemical in many industrial branches, but it can also be found as an ingredient in household products such as cleaning agents. Possessing high corrosive potential, HF acid causes burns and tissue necrosis, while when absorbed and distributed through the bloodstream, its extremely high toxic potential is expressed. Acute symptoms are often followed by pain, particularly in the case of skin burns, which intensiveness does not often correlate with the expressiveness of the clinical findings. Even exposure to low-concentrated solutions or gasses, or low-doses of high-concentrated acid, may provoke delayed systemic disorder which may eventually have a lethal outcome. AIM: Therefore, having information regarding the possible hazardous effects of hydrofluoric acid usage, a variety of symptoms, as well as a treatment approach, is of great importance in the case of HF exposure. METHODS: Available scientific articles published in literature databases, scientific reports and governmental recommendations from the internet websites, written in English, using the following search terms "Hydrofluoric acid, skin burns, eye injury, ingestion, inhalation, systemic toxicity, decontamination, antidote, medical treatment" have been reviewed. RESULTS: This review is useful not only for physicians but for everyone who may come in contact with a person exposed to HF acid. CONCLUSION: It highlights the mechanism of action, presents the acute and chronic symptoms, personal and general protective measures and devices that should be used, as well as decontamination procedures, immediate, antidote and hospital medical treatment.

Contemporary Dental Ceramic Materials, A Review: Chemical Composition, Physical and Mechanical Properties, Indications for Use.

BACKGROUND: The high esthetic expectations from the prosthodontic restorations have directed the qualitative development of the materials towards the all-ceramic materials that are capable of replacing porcelain-fused-to-metal systems. AIM: This article reviews the literature covering the contemporary all-ceramic materials and systems with a focus on the chemical composition and materials' properties; also it provides clinical recommendations for their use. RESULTS: The glass-matrix ceramics and polycrystalline ceramics are presented, as well as recently introduced machinable materials, all-zirconia and resin-matrix ceramics. The specific properties of zirconia, such as transformation toughening, stabilisation of the crystallographic structure, low-temperature degradation and factors affecting the zirconia's ageing, are emphasised. CONCLUSION: The favourable properties of the resin-matrix ceramics, such as modulus of elasticity similar to dentin, shock-absorbing characteristics and high resilience and fracture resistance, are also covered in this article.

Prosthodontics Status and Treatment Needs among the Elderly in the Republic of Macedonia.

BACKGROUND: Oral health care management among the elderly differs from the rest of the population, due to some specific physiological changes and general health status related to age. We know very little about the oral health in elderly in the Republic of Macedonia, because there are only a few articles published about dental health status and edentulism of this population. AIM: The study aimed to evaluate the prosthodontic status of older adults over 65 years in the Republic of Macedonia, about their socio-economic status and individual factors. MATERIAL AND METHODS: A cross-sectional study was conducted in 8 regions, in rural and urban areas of Macedonia and a representative sample of 432 people (age > 65 years) was examined. Statistical analyses of the data were made by chi-square tests and the corresponding C-coefficient. RESULTS: Only 6% of all participants had not any prosthetic appliance, 9.5% had more than one bridge, 28.7% of examinees had partial dentures, both bridge(s) and partial denture(s) had 10.7% participants, and 45.1% of examinees were toothless. There was a significant difference between patients who visited the dentist more than once a year and those who did not (χ2 = 14.2; df = 4, p < 0.01). From all of the participants, 40.3% used public dental care organisations. CONCLUSIONS: We found a high prevalence of edentulousness among older adults over 65 years in Macedonia. The study confirmed the necessity for establishing healthcare educational programs for the dental treatment of elderly in Macedonia.

Acid Etching as Surface Treatment Method for Luting of Glass-Ceramic Restorations, part 1: Acids, Application Protocol and Etching Effectiveness.

AIM: The purpose of this review is to represent acids that can be used as surface etchant before adhesive luting of ceramic restorations, placement of orthodontic brackets or repair of chipped porcelain restorations. Chemical reactions, application protocol, and etching effect are presented as well. STUDY SELECTION: Available scientific articles published in PubMed and Scopus literature databases, scientific reports and manufacturers' instructions and product information from internet websites, written in English, using following search terms: "acid etching, ceramic surface treatment, hydrofluoric acid, acidulated phosphate fluoride, ammonium hydrogen bifluoride", have been reviewed. RESULTS: There are several acids with fluoride ion in their composition that can be used as ceramic surface etchants. The etching effect depends on the acid type and its concentration, etching time, as well as ceramic type. The most effective etching pattern is achieved when using hydrofluoric acid; the numerous micropores and channels of different sizes, honeycomb-like appearance, extruded crystals or scattered irregular ceramic particles, depending on the ceramic type, have been detected on the etched surfaces. CONCLUSION: Acid etching of the bonding surface of glass - ceramic restorations is considered as the most effective treatment method that provides a reliable bond with composite cement. Selective removing of the glassy matrix of silicate ceramics results in a micromorphological three-dimensional porous surface that allows micromechanical interlocking of the luting composite.

Prosthodontic Rehabilitation of Patient with Anterior Hyper Function Syndrome.

BACKGROUND: The success of prosthetic rehabilitation in patients with removable dentures depends on the achievement of the aesthetics, phonetics and most of all, proper use in the mastication process. All the patients that receive removable prostheses need a feeding education program. They must cut the food into smaller pieces, extend the length of time necessary for chewing and place the food upon both the right and left sides of the mouth at once. Bilaterally chewing with dentures will contribute to increased efficiency and denture stability during mastication. Using the anterior teeth for biting, as a result of increased pressure on the anterior ridge may lead to the anterior hyperfunction syndrome. CASE REPORT: The patient requested dental rehabilitation in our clinic for prosthetic dentistry two and a half years ago. We examined him and made therapy plan, for complete removable maxillary denture and partial mandibular denture. Besides our instructions for proper use of dentures and necessity for regular controls, his next visit was after two and a half years. He came with enlarged tuberosity and papillary hyperplasia in the pre-maxillary region. After oral surgery treatment (laser removing of hyperplastic tissue) and a healing period of four weeks, we made indirect relining on the upper denture, re-occlusion and re-articulation achieving weak contacts between the lower natural teeth and upper teeth of the complete denture. The patient was advised not to bite food with his anterior teeth, and avoid chewing very hard food which tends to imprint and displace dentures. CONCLUSION: Anterior hyperfunction syndrome with its high incidence is a disease with the need of interdisciplinary therapy approach. Fast diagnosis, thorough clinical examination using all available diagnostic tools, and choosing the right treatment is very challenging.

Overdentures on Implants for Better Quality of Life Among the Fully Edentulous Patients - Case Reports.

Global aging population has brought several challenges for their medical systems and total edentulism is one of them. The fabrication of removable acrylic dentures seems to be a simple and cheap treatment solution, but a majority of patients is not satisfied with their functional instability, causing limited diets, mouth soreness, speech and psycho-social problems etc. The results in many studies indicate an impact of oral conditions associated with the full denture wearing on oral-health related quality of life, especially in lower jaw. The reason for improper denture retention could be alveolar ridge bone resorption and numerous studies about this problem are plausible. Bone resorption in lower jaw may turn the alveolar ridge into a flabby soft tissue which is unable to sustain proper denture retention. The implant-retained prosthesis is an alternative treatment option in these situations. Implants will provide retention, stability, function and aesthetics and they are not so expensive solution. The aim of this article is to show solving of retention problems of a lower denture in two different clinical cases using implants and without any special technology.