Selected Applications for Current Polymers in Prosthetic Dentistry - State of the Art.

BACKGROUND: Polymers have wide applications in medicine, including dentistry, i.e. in prosthetic dentistry. AIM: The following paper is aimed at demonstrating the applications of selected modern polymers in prosthetic dentistry based on the reported literature. MATERIAL AND METHODS: The study was conducted using the PubMed, SCOPUS and CINAHL databases in relation to documents published during 1999-2017. The following keywords were used: polymers with prosthetic dentistry, impression materials, denture base materials, bite registration materials, denture soft liners, occlusal splint materials and 3D printing. Original papers and reviews which were significant from the modern clinical viewpoint and practical validity in relation to the possibility of using polymeric materials in prosthetic dentistry were presented. RESULTS: Denture base materials were the most commonly modified polymers. Modifications mainly concerned antimicrobial properties and reinforcement of the material structure by introducing additional fibers. Antimicrobial modifications were also common in case of relining materials. CONCLUSION: Polymeric materials have widely been used in prosthetic dentistry. Modifications of their composition allow achieving new, beneficial properties that affect the quality of patients' life. Progress in science allows for a more methodologically-advanced research on the synthesis of new polymeric materials and incorporation of new substances into already known polymeric materials, that will require systematization and appropriate classification.

Do Mechanical and Physicochemical Properties of Orthodontic NiTi Wires Remain Stable In Vivo?

Introduction and Aim. Exceptional properties of the NiTi archwires may be jeopardized by the oral cavity; thus its long-term effect on the mechanical and physiochemical properties of NiTi archwires was the aim of work. Material and Methods. Study group comprised sixty 0.016 × 0.022 NiTi archwires from the same manufacturer evaluated (group A) after the first 12 weeks of orthodontic treatment. 30 mm long pieces cut off from each wire prior to insertion formed the control group B. Obeying the strict rules of randomization, all samples were subjected to microscopic evaluation and nanoindentation test. Results. Both groups displayed substantial presence of nonmetallic inclusions. Heterogeneity of the structure and its alteration after usage were found in groups B and A, respectively. Conclusions. Long-term, reliable prediction of biomechanics of NiTi wires in vivo is impossible, especially new archwires from the same vendor display different physiochemical properties. Moreover, manufacturers have to decrease contamination in the production process in order to minimize risk of mutual negative influence of nickel-titanium archwires and oral environment.

Black stain and dental caries: a review of the literature.

Black stain is characterized as a dark line or an incomplete coalescence of dark dots localized on the cervical third of the tooth. Over the last century, the etiology of black stain has been the subject of much debate. Most of the studies concerning this issue were conducted in pediatric population. According to the reviewed articles published between 2001 and 2014, the prevalence of black stain varies from 2.4% to 18% with equal sex distribution. The majority of the authors confirm the correlation between the presence of black stain and lower caries experience. The microflora of this deposit is dominated by Actinomyces spp. and has lower cariogenic potential than nondiscolored dental plaque. Iron/copper and sulfur complexes are thought to be responsible for the dark color. In patients with black stain saliva has higher calcium concentrations and higher buffering capacity. Factors such as dietary habits, socioeconomic status, and iron supplementation may be contributing to the formation of black stain.

Do the NiTi low and constant force levels remain stable in vivo?

OBJECTIVE: The aim was to evaluate the alteration of the deactivation forces of the most commonly used nickel-titanium wires under long-lasting oral cavity environmental influence. MATERIALS AND METHODS: Randomized in vitro and in vivo trials of 540 pieces of orthodontic archwires, NeoSentalloy®, Copper NiTi® 35°C and Titanol Superelastic(®), round (0.016 inch), and rectangular (0.016 × 0.022 inch), were carried out. Randomization and blinding was achieved with 12-colour system that ensured encoding of key information on the tested specimens. Each of 270 patients (females, 18-20 years old, in the finishing stage of orthodontic treatment) received the piece of NiTi wire ligated piggyback, for a period of 4-6 weeks. Eventually, all samples were subjected to a three-point bending test. Data were statistically analysed at a 5 per cent significance level. RESULTS: In the group of the round used wires, when compared with the new ones, the deactivation force (F dav) values increased significantly for Titanol Superelastic®; the NeoSentalloy® and Copper NiTi® 35°C wires did not change their values of F dav. In the group of rectangular wires, F dav decreased for Titanol Superelastic®, but increased for NeoSentalloy® wires. The F dav values of the Copper NiTi® 35°C used wires practically did not change, but a remarkable increase of the standard deviation was noted. LIMITATIONS: No calculations concerning effectiveness of in vivo aligning of analysed wires were made. CONCLUSIONS: For the purpose of a 4-6-week aligning stage, round NeoSentalloy® with a diameter of 0.016 inches seems to be the wire of choice because of the low level of F dav.

Orthodontic treatment in children with cleft lip and palate repaired using a two-stage surgical correction - authors' experience.

AIM: The purpose of this study was to present and evaluate orthodontic rules and methods in the treatment of children and adolescents with complete cleft lip and palate. MATERIALS AND METHODS: The material consists of about 5500 primary clefts treated at the Hospital and Clinic of Plastic Surgery in Polanica-Zdrój in the years 1976-2008. The most common surgical procedure (>99%) consisted of two-stage repair of cleft lip and palate. In the years 1976-2008, surgical treatment was administered to 5,500 children with a cleft lip and palate. The efficiency of orthodontic procedures is discussed in relation to multidisciplinary cooperation, with a particular emphasis on surgery. CONCLUSIONS: Apart from cleft morphology and the quality of primary surgery, the patients appearance, midface development and occlusal conditions depend on multidisciplinary cooperation, with special regard given to orthodontic treatment.

The impact of the long-term playing of musical instruments on the stomatognathic system - review.

In this article, we have made a review of the influence of playing musical instruments on the formation of malocclusion and TMJ disorders in musicians. Primary attention was paid to the effects of wind and stringed instruments. The aim of the article was the presentation of research and opinions about this problem in the last 25 years. It is reported that long-term and repetitive playing of musical instruments, particularly stringed (violin and viola) and wind instruments can cause dysfunctions of the stomatognathic system. The impact of wind instruments was assessed in terms of the type of mouthpiece. We studied the possibility of repositioning the front teeth and reducing the width of the upper dental arch and overbite. There were also reports on the use of a specific instrument to improve the child's occlusion. Studies have also been performed on the usefulness of relaxation plates in order to improve, and even prevent, dysfunction caused by the constant stress on the same parts of the stomatognathic system. The experiments were mainly based on interviews, dental cast analyses and cephalometric analyses. Additional methods were dynamometer tests and muscle tension palpation.