Relevance of Variations in the Opposing Dentition for the Functionality of Fixed and Removable Partial Dentures: A Systematic Review

The aim of this systematic review was to evaluate the functionality of fixed and removable partial dentures as test interventions in relation to variations in the opposing dentition and their prosthetic restoration. The abstracts identified in the respective databases were screened independently by two investigators. RCTs and uncontrolled studies were considered, provided the patients were included consecutively and the confounding variables were adequately monitored. Seventeen papers were included. The study and publication quality was assessed using a “biometric quality” tool showing an overall poor quality. The reported outcomes, such as survival rates, were in each case obtained from a single study. Two possible trends could be deduced for the endpoint longevity: (a) the first trend in favor of removable partial dentures, compared to fixed partial dentures, with a fully edentulous opposing arch fitted with a removable prosthesis; (b) the second trend in favor of implant-supported partial dentures, compared to conventionally fixed partial dentures, with natural opposing dentition or with a removable partial denture in the opposing arch. No evidence could be generated as to whether, and if so how, variations in the opposing dentition have a bearing on the decision to fit a partially edentulous arch with a fixed or removable partial denture

Uranium mobility in organic matter-rich sediments: A review of geological and geochemical processes

Uranium (U) is of enormous global importance because of its use in energy generation, albeit with potential environmental legacies. While naturally occurring U is widespread in the Earth's crust at concentrations of ~1 to 3 ppm, higher concentrations can be found, includingwithin organicmatter (OM)-rich sediments, leading to economic extraction opportunities. The primary determinants of U behaviour in ore systems are pH, Eh, U oxidation state (U(IV), U(VI)) and the abundance of CO3 2– ions. The concentration/availability and interrelationships among such determinants vary, and the solubility and mobility of ions (e.g. OH-, CO3 2–, PO4 3-, SiO4 4-, SO4 2-) that compete for U (primarily as U(VI)) will also influence the mobility of U. In addition, the presence of OM can influence U mobility and fate by the degree of OMsorption to mineral surfaces (e.g. Fe- and Si- oxides and hydroxides). Within solid-phase OM, microbes can influence U oxidation state and U stability through direct enzymatic reduction, biosorption, biomineralisation and bioaccumulation. The biogenic UO2 product is, however, reported to be readily susceptible to reoxidation and therefore more likely remobilised over longer time periods. Thus several areas of uncertainty remain with respect to factors contributing to U accumulation, stability and/or (re)mobilisation. To address these uncertainties, this paper reviews U dynamics at both geological and molecular scales. Here we identify U-OMbond values that are in agreement, relatively strong, independent from ionic strength and which may facilitate either U mobilisation or immobilisation, depending on environmental conditions. We also examine knowledge gaps in the literature, with U-OM solubility data generally lacking in comparison to data for U sorption and dissolution, and little information available on multi-component relationships, such as UOM-V (V as vanadate). Furthermore, the capability ofOMto influence the oxidation state of U at near surface conditions remains unclear, as it can be postulated that electron shuttling by OM may contribute to changes in U redox state otherwise mediated by bacteria. Geochemical modelling of the environmental mobility of U will require incorporation of data from multi-corporation studies, as well as from studies of U-OM microbial interactions, all of which are considered in this review

Advances in Implant Dentistry—A Special Issue of Dentistry Journal

New knowledge is developing at a rapidly increasing rate in implant dentistry, as in other areas of medicine. [...

Techniques to Preserve Keratinized Peri-Implant Mucosa in CT-Guided Oral Implant Surgery

Guided implant dentistry using computed tomographic (CT) scans, virtual planning software and mucosa-supported surgical templates is an upcoming technology with the potential for more predictable and less invasive implant placement. While generally associated with a flapless approach, soft tissue punching and removal may not be indicated if available width of keratinized mucosa is limited prior to implant surgery. Two techniques to preserve keratinized peri-implant mucosa (Punch Reposition Technique and Topical Flap Technique) are presented and indications outlined. Appreciation of soft tissue conditions as well as functional and esthetic consequences of mucosal deficiencies (mucosal-driven approach) is recommended to supplement bone- and prosthetic-driven considerations in guided oral implant placement (Trinity Approach)

Minimally invasive elevation of the sinus membrane for maxillary bone augmentation

Die transkrestale Elevation der Kieferhöhlenschleimhaut ermöglicht minimalinvasive Knochenaugmentation zur Impantatversorgung im zahnlosen posterioren Oberkiefer. Die vorliegende Dissertation behandelt chirurgische Durchführung sowie präoperative Planung einer innovativen Technik zur Membranelevation mittels Gel-Druck. Experimentelle Humanleichenstudien und computertomographische Analysen beleuchten den Einfluss der internen Kieferhöhlenanatomie und der biomechanischen Eigenschaften der Kieferhöhlenschleimhaut auf die maximale Höhe der Membranelevation. Kieferhöhlensepten sowie die Primärstabilität von simultanen Implantaten werden untersucht. Ergebnisse klinischer Studien über Methoden der transkrestalen Osteotomie und Knochenregeneration nach Sinusbodenaugmentation werden dargelegt.Transcrestal elevation of the maxillary sinus membrane provides a minimally invasive treatment option to augment bone volume for implant placement in the edentulous posterior maxilla. The present thesis details on the surgical as well as preoperative plannung procedures of a innovative technique to elevate the sinus membrane using gel pressure. The influence of internal maxillary sinus anatomy and biomechanical properties of the maxillary sinus membrane on maximum membrane elevation height is studied in human cadaver experiments and computed tomography-based analyses. Maxillary sinus septa and primary stability of simultaneously placed implants are investigated. Clinical study results on methods of transcrestal osteotomy and bone regeneration following maxillary sinus floor augmentation are presented.submitted by Bernhard PommerZusammenfassung in dt. SpracheWien, Med. Univ., Diss., 2011OeBB(VLID)271241

The influence of crown-to-implant ratio on marginal bone levels around splinted short dental implants: A radiological and clincial short term analysis

BACKGROUND The amount of marginal bone resorption around dental implants is considered to have a significant impact on implant stability as well as implant survival rates. PURPOSE The aim of this prospective study was to investigate the influence of prosthetic as well as patient specific factors on marginal bone loss around short dental implants. MATERIALS AND METHODS Seventy-six implants, which supported splinted crowns were included for investigation. All implants were from the same type and had an intraosseous length of 6.5 mm and a diameter of 4.0 mm. Twenty implants were additionally splinted onto longer ones. Measurements of marginal bone loss were performed at a mean of 12.38 months after prosthetic loading and the mean follow-up for clinical evaluation was 20.52 months. RESULTS Overall two implant failures were recorded, revealing a survival rate of 97.3%. Marginal bone resorption around 72 short implants measured 0.71 mm (SD: 0.74 mm) and was found to have a strong correlation with calculated Crown-to-Implant ratio (r = .71; P < .001). Age, gender, insertion torque, implant surface area, location, position, bone quality, and insertion torque did not influence peri-implant bone loss after one year of loading. CONCLUSION Within the limitations of the study, it is suggested that Crown-to-Implant ratios should not exceed 1.7 to avoid increased early marginal bone loss

Dynamic finite element modeling of transcrestal sinus membrane elevation for maxillary bone augmentation

Alveolar resorption following tooth loss frequently limits bone volume available for dental implant placement in the posterior maxilla. Maxillary sinus floor augmentation is routinely carried out via a lateral approach, however, associated with patient morbidity [Chiapasco, 2009]. Transcrestal surgical techniques for sinus membrane elevation have thus been developed [Summers, 1998], the minimally-invasive approach, however, carries an increased risk of membrane perforation [Lozada, 2011].status: publishe