SAMMANFATTNING Bakgrund: Kunskapen om helkeramiska kronor är begränsad och få studier är gjorda inom allmäntandvård. Syfte: Projektet hade i syfte att undersöka femårsöverlevnaden för helkeramiska kronor samt att utvärdera om patientens kön, typ av porslin, typ av cement, rotfyllnadsstatus och tandposition påverkade överlevnaden. Material och metod: Studien är en retrospektiv journalstudie. Samtliga patienter som under åren 2008-2009 behandlades med en helkeramisk, krona på en kindtand inkluderades, totalt 297 kronor. Kronorna följdes sedan upp i fem år. Resultat: Kronöverlevnaden efter fem år var 91,6 %, ingen skillnad sågs mellan kronor utförda på kvinnor och män eller beroende på typ av porslin och typ av cement. Endokronor hade en något lägre överlevnad, 82,8 %, jämfört med fullkronor, 90,9 % och onlaykronor 100 % (p=0,081). Ingen skillnad sågs i överlevnad beroende på tandposition. Slutsats: Femårsöverlevnaden för keramiska kronor i sidopartier utförda inom allmäntandvården är god Den vanligaste komplikationen, oavsett krontyp, var lossnad krona.

<p><b>Aims and Hypothesis</b>: The objective of this study was the design and testing of a Prototype Computer Numerical Control (CNC) dental handpiece. We predicted that the CNC Prototype would be more accurate than the human participant prosthodontists in clinical simulation. </p><p> <b>Materials and Methods</b>: A Prototype CNC dental handpiece was developed from off the shelf components, assigned 100 typodont teeth (#18) for submission and 10 practice teeth. Single operator. Five prosthodontists, given 20 typodont teeth (#18) for submission and 10 for practice. Finished preparations were scanned with 3M True Definition^&reg; intraoral scanner outside of typodont, compared with Geomagic Control for RMSE. </p><p> <b>Results</b>: RMSE Prototype (N=100) was 0.40mm. RMSE Prosthodontists (N=100) was 0.55mm. One sided T test, mean difference &minus;.15mm (p&lt;.001, one sided CI &minus;.09). One Way ANOVA (F stat &lt;1, F=.526, p=.717), Spearman correlation Prototype RMSE vs order(&rho;=.1, p=.334), RMSE vs Bur (&rho;=.36, p&lt;.001); For each prosthodontist individually (N=20) RMSE vs Order Prosthodontist 4(&rho;=&minus;.54, p= .015). Prosthodontist 5 (&rho;= .58, p = .022). Prosthodontist 3 (&rho;=.16, p=.498), Prosthodontist 2 (&rho;=&minus;.07, p=.772), and Prosthodontist 1 (&rho;=&minus;.08, p=.741) Spearman correlation (N=20) RMSE vs Bur Prosthodontist 5 (&rho;= .51, p = .007), Prosthodontist 2 (&rho;=.46, p= .040), Prosthodontist 4 (&rho;=&minus;.07, p=.758), Prosthodontist 3 (&rho;=.18, p=.445), and Prosthodontist 1 (&rho;=.43, p=.059) </p><p> <b>Conclusion</b>: CNC Prototype achieved superior results in clinical simulation, attained on a modest budget with a modest level of research support. Work should continue on the next iteration of a prototype to address some of the limitations of movement, feedback, and emotional acceptance of a machine performing treatment from the perspective of a patient. </p>

<p> Background: The literature indicates a reduced survival rate for dental implants placed at previously failed sites, smokers, and patients with a history of periodontal disease. The aim of this study is to review the available literature reporting on the success and/or survival of rough surface implants placed at previously failed sites, in smokers, and in periodontally compromised patients. An attempt was made to systematically review the literature and calculate an overall weighted mean survival rate for rough surface implants in each of the above three scenarios. </p><p> Methods: An electronic literature search (MEDLINE-PubMed) was performed and references hand-searched for human studies addressing the success/survival of implants placed at previously failed sites, in smokers and in patients with a history of chronic periodontal disease. The overall weighted mean survival rates and 95% confidence interval were then calculated. Results: Six retrospective studies reporting on implants placed at previously failed sites were included with total of 343 second attempts and 31 third attempts at implant placement at failed sites in 330 patients. The weighted mean survival rates for the second and third attempts at implant placement in a previously failed site were calculated to be 88.05% and 74.19%, respectively. A total of 14,395 implants were included in smoking analysis. Of these, 10,403 implants were placed in non-smokers with 250 failures and 3,992 placed in smokers, with 205 failures. The calculated overall weighted mean implant-level survival was 97.67% in non-smokers and 95.03% for in smokers. Lastly, six studies reported on 591 implants placed in periodontally compromised patients with a total of 15 failures and 198 implants placed in periodontally healthy patients with just one failure. The overall weighted mean implant survival rate was calculated to be 97.48% in periodontally compromised patients compared to 99.49% for periodontally healthy patients. </p><p> Conclusions: Of the three risk factors evaluated in this review, rough surface implants placed in previously failed sites presents the highest risk for implant failure. Rough surface implant survival declines significantly for each additional attempt at implant placement at a previously failed site, with weighted mean survival rates of 88.05% and 74.19% for the second and third attempts, respectively. Although more favorable than previously used implant designs, smokers continue to experience lower survival rates compared to non-smokers, with overall weighted mean implant survival rates of 95.03% and 97.67%, respectively. A similar finding was found for implants placed in patients with a history of chronic periodontitis. The calculated weighted mean survival rate was 99.49% for periodontally healthy patients compared to 97.48% for periodontally compromised patients.</p>

<p> Background: Corticosteroid medications have been researched extensively in oral surgery procedures for the proposed reduction in trismus, swelling, and pain. No consensus has been determined for the most efficacious type, timing, and dosage of medication thus far. In addition little is known about the usage of corticosteroids for periodontal and implant related procedures. The aims of this review are to help clinicians understand the usage of corticosteroid medications in various dental surgeries.</p><p> Methods: The PubMed-MEDLINE and the Cochrane-CENTRAL databases were searched through and up till June 2015 to identify appropriate studies regarding this aim. Appropriate studies were those reporting on the usage of corticosteroids related to its pathophysiology, surgical related outcomes, and patient related outcomes in dental procedures. Conclusions: The search yielded 256 unique papers after selection resulted in 12 publications that met the eligibility criteria. In general the usage of corticosteroids in third molar extractions improved post operatives outcomes related to edema, trismus, and a slight reduction in pain. However, It cannot be recommended to use corticosteroids for pain management. Due to the various types, routes, and dosages of corticosteroid used in studies, no specific drug, route, or dosage can be recommended by literature. The usage of corticosteroids for periodontal and implant related procedures has not been investigated. Further research is required to investigate the possible benefits of corticosteroids on reduction of surgical swelling in periodontal and implant related surgeries.</p>

<p> <i><u>Introduction:</u></i></p><p> Medication related osteonecrosis of the jaw (MRONJ) is exposed bone in the maxillofacial region that does not heal within eight weeks after identification by a health professional. Cancer patients taking or who have a history of taking anti-resorptive or anti-angiogenic agents have an increased risk for MRONJ. MRONJ adversely affects quality of life and results in significant morbidity. It has been shown that patients with risk factors for MRONJ are not aware of the condition or preventive strategies. Understanding patient awareness is the first step in communicating strategies for the prevention of and management of MRONJ.</p><p> <i><u>Aim of the study:</u></i></p><p> To describe the awareness level and characteristics, such as education level, of MRONJ among Roswell Park Cancer Institute (RPCI) patients who receive dental services in the RPCI dental clinic.</p><p> <i><u>Material and Methods:</u></i></p><p> This is a prospective interviewer administered research electronic data capture (REDCap) survey project. The sample include RPCI dental patients who are at least 18 years old with a history of taking, currently taking or will be taking Bisphosphonate, Denosumab, and/or Anti-angiogenic agent as part of their treatment at RPCI and volunteered to participate in the study. Patients were screened for eligibility by an RPCI dentist. Selected patients have been asked 21 questions.</p><p> <i><u>Results:</u></i></p><p> Twenty patients, 10 males and 10 females, participated in this study. The age of our subjects were ranging from 23 to 82 years. Eleven patients have completed a college degree or above, five have completed a high school diploma, and four have some college. Out of 20, nine patients only were aware of osteonecrosis of the jaw (ONJ). No relation has been found between ONJ awareness and gender, education level, or age.</p><p> <i><u>Conclusion:</u></i></p><p> This study shows that awareness of medication-related osteonecrosis of the jaw is poor amongst oncology patients who are at risk of MRONJ. There was no relation between age, gender, or education level and ONJ awareness in oncology patients. An effort to educate users of bisphosphonate, denosumab, bevacizumab, and sunitinib about their medications and their potential side effects as well as including preventative measures must be pursued. Health care providers, especially dentists, must be aware of MRONJ and its risk factors. In addition, they should know the significance of their role in educating and preventing the condition by following their health practice guidelines as well as applying the necessary preventive measures on their patients.</p>

Denture soft lining materials are used as a cushion between the hard denture base and the oral mucosa. Fluid sorption and solubility may contribute to material hardening, roughening, cracking or tearing, loss of adhesion to the hard denture base or contamination by extrinsic stains or yeasts. The ideal material is required to have low fluid uptake, good wettability, retain compliance and surface integrity, and not support fungal growth. Evaluation of behaviour in the oral environment is difficult and a number of materials, such as artificial saliva and food simulating liquids, have been recommended to simulate the environment. The two types of denture soft lining materials commonly used in clinical practice are methacrylate and silicone based. These together with an experimental elastomer were evaluated in this study. Fluid sorption and solubility were determined by immersion of disc specimens in food simulating fluids (distilled water, 3% acetic acid, 10% ethanol and 50% ethanol) and artificial saliva at 37±1°C with weighing at set time intervals. Similar experiments were carried out using liquids representing fatty food constituents with coconut oil and 1113307H. ardness was determined using a Shore A durometer. In order to determine wettability, contact angle was measured using a computer microscope. The surface roughness was assessed using a non-contact laser profilometer. Finally, an attempt was made to identify leachable substances from the materials investigated using a Fourier transform infrared spectrometer. An additional part of this study was to look at the adhesion of one yeast species Candida albicans to commercial materials using various protective coatings to determine their efficacy. The resultsd emonstratedth at the type of liquid simulating foods or artificial saliva, and immersion time significantly influenced the behaviour of the commercial denture soft lining materials and the experimental elastomer during in vitro testing. The two groups of materials behaviour were different. The two methacrylate-basedd enture soft lining materials showed marked absorption and solubility which may be associated with the loss of plasticisers. The two silicone-based denture soft lining materials showed much less absorption and solubility under the same conditions. The experimental elastomer showed marked swelling in oils, which was not expected, its chemical structure being similar to a methacrylate. Shore A hardness remained unchanged during the fluid immersion with the two silicone-based materials but showed measurable changes with the two methacrylate-basemd aterials and the experimentale lastomer,I ncreaseds urface roughness was also demonstrated with the two methacrylate-based materials, and decreasedc ontact angle was found with the two silicone-basedm aterials. After various surface treatment, coconut oil reduced Candida albicans adhesion in all cases.

Clinical observation suggest that bone formation is influenced by the environmental niche where it takes place and specifically that soft connective tissues may inhibit the bone healing process. The aim of the studies described in this thesis is to test the hypothesis that fibroblasts inhibit the differentiation and function of osteoblasts in vitro. To address this aim the ability of fibroblasts and their supernatants to inhibit osteoblast differentiation was investigated. In addition, the inhibitory effects of gingival and periodontal ligament fibroblasts were compared. Next Bone Morphogenetic Proteins (BMPs) and their antagonists were tested for their ability to modulate the activity of fibroblast supernatants. Finally the effects of fibroblast supernatants on osteoblast chemotactic responses were investigated. Primary fibroblasts were isolated from rat gingivae, skin, oral mucosa and periodontal ligament (PDL) using explant cultures. Primary osteoblast cultures were established by enzymatic digestion of neonatal rat calvariae. In other experiments the osteoblastic cell line ROS 17/2.8 was used. Osteoblast differentiation was assessed by measuring alkaline phosphatase (ALP). In co-culture experiments using 3-D collagen gels and diffusion chamber inserts fibroblasts strongly inhibited osteoblast differentiation. Furthermore conditioned medium from superficial connective tissues fibroblasts consistently inhibited osteoblast differentiation (greater than 50% inhibition of ALP expression. In contrast, PDL cells strongly stimulated ALP expression (greater than 100% increase). Stimulation of ROS 17/2.8 cells with BMP-2 increased ALP expression (more than 3 fold increase with 10ng/ml BMP-2), and this effect could be completely blocked by the BMP-antagonist 100ng/ml noggin. Similarly conditioned media from gingival, oral mucosal and skin fibroblasts totally suppressed the effects of BMP-2. In contrast, PDL conditioned media stimulated ALP expression in additively with BMP-2, and his effect could also be blocked by noggin. Using a micro-well Boyden Chamber both PDGF and BMP-2 caused a dose-dependent increase in chemotaxis. However fibroblast conditioned medium totally blocked the chemotactic effects on BMP-2, but had no effect on PDGF-induced chemotaxis. Overall these studies demonstrate that fibroblasts from superficial connective tissues (gingival, oral mucosa and skin) can inhibit osteoblast function by secretion of BMPantagonists and that superficial connective tissues and PDL are distinct in respect to their role in bone healing. Further studies are needed to identify the specific molecular identity of this inhibitory activity and to extend these observations to an in vitro model. However in the longer term it is proposed that information on the regional expression of BMP inhibitors may lead to novel therapeutic interventions to promote bone growth in periodontal and implant related bone regeneration procedures.

Calcium phosphate cements are in-vivo setting, injectable calcium phosphate based biomaterials. They are made of calcium phosphate salts which when mixed with water react to form apatite, the mineral phase of bones and teeth. This study investigates a novel way of forming calcium phosphate cements using bioactive glasses. The aim of the work was to discover a novel route of synthesis using a silicate bioactive glass. Fifteen glass compositions were produced designed to investigate P2O5 content, CaF2 content and calcium to sodium ratio within the glass. Glasses were produced via a melt-quench route before being milled and sieved to below 38 μm. The bioactive glass and Ca(H2PO4)2 powders were mixed in an overall calcium to phosphate ratio of 1.67. The cement powder was then reacted with a 2.5 % solution of Na2HPO4. The paste was then mixed and then placed into cylindrical moulds. Eight samples were immersed into Tris buffer solution for 1 hour, 1 day, 7 days or 28 days. The compressive strength was measured for each specimen as well as SEM performed and the setting times for each composition was studied using the Gilmore needle test. The cement phase was analysed using 31P & 19F MAS-NMR, FTIR and XRD. The results showed that both compressive strength and setting time was dependent upon glass composition. As sodium content was increased both the initial and final setting times decreased. Increased fluoride addition caused a decrease in the setting time. In the fluoride free compositions octacalcium phosphate was identified in all compositions. The cement setting reaction for these compositions followed a similar reaction of first forming dicalcium phosphate dihydrate which transformed to octacalcium phosphate then eventually hydrolysing to hydroxyapatite. When fluoride was incorporated into the cement the phases formed were fluoridated-apatite and DCPD. In conclusion a novel method of producing calcium phosphate cements was discovered using a bioactive glass as a reactive precursor. It was shown that the cement phase, setting time and compressive strength could all be altered by changing the glass composition.

The prevalence of developmental enamel defects in t11 permanent dentition was investigated in a sample of 2923 East London schoolchildren aged 5 to 15 years. Enamel discolourations and hypoplasias were identified using well defined criteria. Two-thirds of the children had at least one tooth with- an enamel defect. In the group of 1518 children with 24-28 erupted permanent teeth, 68 per cent had enamel defects with. a mean of 3.6 per child. The upper central Incisors and first molars had the highest prevalence of enamel defects. In these teeth., the proportion of defects decreased with.. age. The majority of defects were discolourations; 67 per cent of children..with a "complete" -permanent dentition had discolouration defects whereas only iS. per cent had enamel bypoplasia. The aetiology of defects-found in children with. two or more hypoplastic teeth was investigated in a family study. Four of the 101 index cases had amelogenesis imperfecta and 18 had chronological hypoplasia caused by systemic diseases. The defects in a further 18 subjects had a probable systemic aetiology. Bilateral hypoplasia of the lower incisors was found in 22 subjects and a multifactoria]. mode of inheritance was postulated for this condition. For one third of the index cases no cause could be found for their hypoplasia. A histological study. complemented thesurveys by describing structural characteristics of different types of enamel defects. The investigation highlighted a number of differences between enamel defects caused by systemic upsets and those caused by genetic factors. An archaelogical. study assessedthe prevalence-of enamel h-ypoplasia in a cällection of early British skulls. Thirty-seven per cent had a number of hypoplastic teeth. There were few severe cases of hypoplasia; the most common type of defect being shallow horizontal grooves. The many teeth with shallow defects suggested periodic disturbances in enamel formation between 2 and 6 years of age. This thesis has provided further information about the complex nature of enamel defects. The different aspects of enamel defects which have been investigated have contributed to a greater understanding of their prevalence, aetiology and histology.

In recent years there has been an increasing awareness of the influence of various trace elements on reducing the progression of dental caries and of erosion. However, there are few clinical and even fewer in-vitro studies of the cariostatic effect of some trace elements on the progression of dental caries. Further, there is currently no consensus on the underlying physico-chemical mechanism on the influence of trace elements on these processes. The aim of this study was to investigate the effect of three divalent cations; zinc (Zn2+), strontium (Sr2+) and copper (Cu2+), on the physical-chemistry influencing hydroxyapatite (HAp) dissolution kinetics, using scanning microradiography (SMR), under simulated cariogenic and erosive conditions relevant to the oral environment. Compressed and sintered porous HAp discs were used as model systems for dental enamel. These discs were exposed to demineralising solutions containing a range of concentrations of Zn2+, Sr2+ and Cu2+, and either 0.1% acetic acid at pH 4.0 resembling dental caries, or 0.3% citric acid at pH 2.8 resembling erosion conditions. SMR is a development of the photographic microradiography technique of mineral quantification by means of X-ray absorption, but allows real-time quantification measurement of the rate of HAp mineral loss (RDHAp). Sequential SMR experiments during which the HAp disc was exposed to demineralising solution, containing each cation in either increasing or decreasing concentration order (separated by 30 minutes of washing with de-ionised water) allowed evaluation of the persistence of the influence of the divalent cations being investigated. The results showed that all three divalent cations decreased RDHAp significantly under both investigated conditions but via two different mechanisms. It was proposed that Zn2+ and Cu2+ decrease the RDHAp through a surface controlled mechanism whereas Sr2+ decreases the RDHAp through a solid phase change. This information will be useful as part of the development of therapeutic products which include these ions for the prevention of dental caries and erosion