Early implant placement with simultaneous guided bone regeneration following single-tooth extraction in the esthetic zone: 12-month results of a prospective study with 20 consecutive patients

BACKGROUND: Early implant placement is one of the treatment options in postextraction sites in the anterior maxilla. Implant placement is performed after a soft tissue healing period of 4 to 8 weeks. Implant placement is combined with a simultaneous guided bone regeneration (GBR) procedure to rebuild esthetic facial hard and soft tissue contours. METHODS: In this prospective case-series study, 20 consecutive patients treated with an implant-borne single crown were prospectively followed for 12 months. Clinical, radiologic, and esthetic parameters were recorded to assess treatment outcomes. RESULTS: At the 12-month examination, all 20 implants were successfully integrated, demonstrating ankylotic stability and healthy peri-implant soft tissues as documented by standard parameters. The esthetic outcomes assessed by a pink esthetic score (PES) and a white esthetic score (WES) demonstrated pleasing results overall. The WES values were slightly superior to the PES values. The periapical radiographs showed minimal crestal bone loss around the used bone level implants, with mean bone loss of 0.18 mm at 12 months. Only one implant showed >0.5 mm bone loss, combined with minor mucosal recession of 0.5 to 1.0 mm. CONCLUSIONS: This prospective case series study evaluating the concept of early implant placement demonstrated successful tissue integration for all 20 implants. The short-term follow-up of 12 months revealed pleasing esthetic outcomes overall, as assessed by objective parameters. The risk for mucosal recession was low; only one patient showed minor recession of the facial mucosa. These encouraging results need to be confirmed with 3- and 5-year follow-up examinations.

Long-term stability of contour augmentation with early implant placement following single tooth extraction in the esthetic zone: a prospective, cross-sectional study in 41 patients with a 5- to 9-year follow-up

BACKGROUND Early implant placement with simultaneous contour augmentation is documented with short- and medium-term studies. The long-term stability of contour augmentation is uncertain. METHODS In this prospective, cross-sectional study, 41 patients with an implant-borne single crown were examined twice, in 2006 and 2010. Clinical, radiologic, and esthetic parameters were assessed at both examinations. In addition, a cone beam computed tomographic (CBCT) image was obtained during the second examination to assess the dimensions of the facial bone wall. RESULTS All 41 implants demonstrated ankylotic stability without signs of peri-implant infection at both examinations. The clinical parameters remained stable over time. Satisfactory esthetic outcomes were noted, as assessed by the pink and white esthetic score (PES/WES) indices. Overall, the PES scores were slightly higher than the WES scores. None of the implants developed mucosal recession over time, as confirmed by values of the distance between implant shoulder and mucosal margin and cast measurements. The periapical radiographs yielded stable peri-implant bone levels, with a mean distance between implant shoulder and first visible bone-implant contact value of 2.18 mm. The CBCT analysis demonstrated a mean thickness of the facial bone wall ≈2.2 mm. In two implants (4.9%) no facial bone wall was detectable radiographically. CONCLUSIONS This prospective cross-sectional study demonstrates stable peri-implant hard and soft tissues for all 41 implants examined and satisfactory esthetic outcomes overall. The follow-up of 5 to 9 years confirmed again that the risk for mucosal recession is low with early implant placement. In addition, contour augmentation with guided bone regeneration was able to establish and maintain a facial bone wall in 95% of patients.

All-ceramic or metal-ceramic tooth-supported fixed dental prostheses (FDPs)? A systematic review of the survival and complication rates. Part I: Single crowns (SCs).

OBJECTIVE To assess the 5-year survival of metal-ceramic and all-ceramic tooth-supported single crowns (SCs) and to describe the incidence of biological, technical and esthetic complications. METHODS Medline (PubMed), Embase, Cochrane Central Register of Controlled Trials (CENTRAL) searches (2006-2013) were performed for clinical studies focusing on tooth-supported fixed dental prostheses (FDPs) with a mean follow-up of at least 3 years. This was complimented by an additional hand search and the inclusion of 34 studies from a previous systematic review [1,2]. Survival and complication rates were analyzed using robust Poisson's regression models to obtain summary estimates of 5-year proportions. RESULTS Sixty-seven studies reporting on 4663 metal-ceramic and 9434 all-ceramic SCs fulfilled the inclusion criteria. Seventeen studies reported on metal-ceramic crowns, and 54 studies reported on all-ceramic crowns. Meta-analysis of the included studies indicated an estimated survival rate of metal-ceramic SCs of 94.7% (95% CI: 94.1-96.9%) after 5 years. This was similar to the estimated 5-year survival rate of leucit or lithium-disilicate reinforced glass ceramic SCs (96.6%; 95% CI: 94.9-96.7%), of glass infiltrated alumina SCs (94.6%; 95% CI: 92.7-96%) and densely sintered alumina and zirconia SCs (96%; 95% CI: 93.8-97.5%; 92.1%; 95% CI: 82.8-95.6%). In contrast, the 5-year survival rates of feldspathic/silica-based ceramic crowns were lower (p<0.001). When the outcomes in anterior and posterior regions were compared feldspathic/silica-based ceramic and zirconia crowns exhibited significantly lower survival rates in the posterior region (p<0.0001), the other crown types performed similarly. Densely sintered zirconia SCs were more frequently lost due to veneering ceramic fractures than metal-ceramic SCs (p<0.001), and had significantly more loss of retention (p<0.001). In total higher 5 year rates of framework fracture were reported for the all-ceramic SCs than for metal-ceramic SCs. CONCLUSIONS Survival rates of most types of all-ceramic SCs were similar to those reported for metal-ceramic SCs, both in anterior and posterior regions. Weaker feldspathic/silica-based ceramics should be limited to applications in the anterior region. Zirconia-based SCs should not be considered as primary option due to their high incidence of technical problems.

Cheek Tooth Extraction Via a Minimally Invasive Transbuccal Approach and Intradental Screw Placement in 54 Equids

OBJECTIVE: To describe (1) preoperative findings and surgical technique, (2) intraoperative difficulties, and (3) postoperative complications and long-term outcome of equine cheek tooth extraction using a minimally invasive transbuccal screw extraction (MITSE) technique. STUDY DESIGN: Retrospective case series. ANIMALS: Fifty-four equids; 50 horses, 3 ponies, and 1 mule. METHODS: Fifty-eight MITSE procedures were performed to extract cheek teeth in 54 equids. Peri- and intraoperative difficulties, as well as short- (<1 month) and long-term (>6 months) postoperative complications were recorded. Followup information was obtained through telephone interviews, making specific inquiries about nasal discharge, facial asymmetry, and findings consistent with surgical site infection. RESULTS: Preoperative findings that prompted exodontia included 50 cheek teeth with apical infections, 48 fractures, 4 neoplasia, 2 displacements, and 1 supernumerary tooth. Previous oral extraction was attempted but had failed in 55/58 (95%) animals because of cheek tooth fracture in 28, or insufficient clinical crown for extraction with forceps in 27. MITSE was successful in removing the entire targeted dental structure in 47/58 (81%) procedures. However, MITSE failed to remove the entire targeted dental structure in 11/58 (19%) procedures and was followed by repulsion in 10/11 (91%). Short-term postoperative complications included bleeding (4/58 procedures, 7%) and transient facial nerve paralysis (4/58 procedures, 7%). Owners were satisfied with the functional and cosmetic outcome for 40/41 (98%) animals with followup. CONCLUSION: MITSE offers an alternate for cheek tooth extraction in equids, where conventional oral extraction is not possible or has failed. Overall, there was low morbidity, which compares favorably with invasive buccotomy or repulsion techniques

Changes of Root Length and Root-to-Crown Ratio after Apical Surgery: An Analysis by Using Cone-beam Computed Tomography

INTRODUCTION Apical surgery is an important treatment option for teeth with post-treatment periodontitis. Although apical surgery involves root-end resection, no morphometric data are yet available about root-end resection and its impact on the root-to-crown ratio (RCR). The present study assessed the length of apicectomy and calculated the loss of root length and changes of RCR after apical surgery. METHODS In a prospective clinical study, cone-beam computed tomography scans were taken preoperatively and postoperatively. From these images, the crown and root lengths of 61 roots (54 teeth in 47 patients) were measured before and after apical surgery. Data were collected relative to the cementoenamel junction (CEJ) as well as to the crestal bone level (CBL). One observer took all measurements twice (to calculate the intraobserver variability), and the means were used for further analysis. The following parameters were assessed for all treated teeth as well as for specific tooth groups: length of root-end resection and percentage change of root length, preoperative and postoperative RCRs, and percentage change of RCR after apical surgery. RESULTS The mean length of root-end resection was 3.58 ± 1.43 mm (relative to the CBL). This amounted to a loss of 33.2% of clinical and 26% of anatomic root length. There was an overall significant difference between the tooth groups (P < .05). There was also a statistically significant difference comparing mandibular and maxillary teeth (P < .05), but not for incisors/canines versus premolars/molars (P = .125). The mean preoperative and postoperative RCRs (relative to CEJ) were 1.83 and 1.35, respectively (P < .001). With regard to the CBL reference, the mean preoperative and postoperative RCRs were 1.08 and 0.71 (CBL), respectively (P < .001). The calculated changes of RCR after apical surgery were 24.8% relative to CEJ and 33.3% relative to CBL (P < .001). Across the different tooth groups, the mean RCR was not significantly different (P = .244 for CEJ and 0.114 for CBL). CONCLUSIONS This CBCT-based study demonstrated that the RCR is significantly changed after root-end resection in apical surgery irrespective of the clinical (CBL) or anatomic (CEJ) reference levels. The lowest, and thus clinically most critical, postoperative RCR was observed in maxillary incisors. Future clinical studies need to show the impact of resection length and RCR changes on the outcome of apical surgery.

Salivary Gland and Tooth Abnormalities Massively Increase Caries Susceptibility in A Mouse Model of Cleft Lip/Palate

Thesis (Ph.D.)--University of Washington, 2016-04

Does psychological stress mediate social deprivation in tooth loss?

It is unclear which theoretical dimension of psychological stress affects health status. We hypothesized that both distress and coping mediate the relationship between socio-economic position and tooth loss. Cross-sectional data from 2915 middle-aged adults evaluated retention of < 20 teeth, behaviors, psychological stress, and sociodemographic characteristics. Principal components analysis of the Perceived Stress Scale (PSS) extracted 'distress' (a = 0.85) and 'coping' (a =0.83) factors, consistent with theory. Hierarchical entry of explanatory variables into age- and sex-adjusted logistic regression models estimated odds ratios (OR) and 95% confidence intervals [95% CI] for retention of < 20 teeth. Analysis of the separate contributions of distress and coping revealed a significant main effect of coping (OR = 0.7 [95% CI = 0.7-0.8]), but no effect for distress (OR = 1.0 [95% CI = 0.9-1.1]) or for the interaction of coping and distress. Behavior and psychological stress only modestly attenuated socio-economic inequality in retention of < 20 teeth, providing evidence to support a mediating role of coping.

Towards automatic tree crown detection and delineation in spectral feature space using PCNN and morphological reconstruction

The application of object-based approaches to the problem of extracting vegetation information from images requires accurate delineation of individual tree crowns. This paper presents an automated method for individual tree crown detection and delineation by applying a simplified PCNN model in spectral feature space followed by post-processing using morphological reconstruction. The algorithm was tested on high resolution multi-spectral aerial images and the results are compared with two existing image segmentation algorithms. The results demonstrate that our algorithm outperforms the other two solutions with the average accuracy of 81.8%.

Toward robust image detection of crown-of-thorns starfish for autonomous population monitoring

Robust texture recognition in underwater image sequences for marine pest population control such as Crown-Of-Thorns Starfish (COTS) is a relatively unexplored area of research. Typically, humans count COTS by laboriously processing individual images taken during surveys. Being able to autonomously collect and process images of reef habitat and segment out the various marine biota holds the promise of allowing researchers to gain a greater understanding of the marine ecosystem and evaluate the impact of different environmental variables. This research applies and extends the use of Local Binary Patterns (LBP) as a method for texture-based identification of COTS from survey images. The performance and accuracy of the algorithms are evaluated on a image data set taken on the Great Barrier Reef.

Dealing with unique interests in Crown Land : a Queensland perspective

Security of tenure is the cornerstone of the land management system in Australia. Freehold title is protected throug indefeasibility of title entrenched in legislation and protection of registrable interests in land is offered through the Statutory Assurance Fund. For those with interests pertaining to Crown Land no such protection is offered, although this position is not uniform across Australia. Notably those with Crown leasehold interests or a profit a prendre on Crown Land in Queensland are not protected through registration on the freehold land register and do not have the benefit of indefeasibility of title. The issue of management of interests pertaining to Crown Land has become increasingly relevant due to the complexities associated with balancing public interests including native title with more commercial interests in land generated through carbon sequestration, forestry and mining. This paper considers the framework for the management of Crown Land in Queensland and the adequacy of this framework for commercial interests that pertain to Crown Land.

Crown copyright

Copyright protects much of the creative, cultural, educational, scientific and informational material generated by federal, State/Territory and local governments and their constituent departments and agencies. Governments at all levels develop, manage and distribute a vast array of materials in the form of documents, reports, websites, datasets and databases on CD or DVD and files that can be downloaded from a website. Under the Copyright Act 1968 (Cth), with few exceptions government copyright is treated the same as copyright owned by non-government parties insofar as the range of protected materials and the exclusive proprietary rights attaching to them are concerned. However, the rationale for recognizing copyright in public sector materials and vesting ownership of copyright in governments is fundamentally different to the main rationales underpinning copyright generally. The central justification for recognizing Crown copyright is to ensure that government documents and materials created for public administrative purposes are disseminated in an accurate and reliable form. Consequently, the exclusive rights held by governments as copyright owners must be exercised in a manner consistent with the rationale for conferring copyright ownership on them. Since Crown copyright exists primarily to ensure that documents and materials produced for use in the conduct of government are circulated in an accurate and reliable form, governments should exercise their exclusive rights to ensure that their copyright materials are made available for access and reuse, in accordance with any laws and policies relating to access to public sector materials. While copyright law vests copyright owners with extensive bundles of exclusive rights which can be exercised to prevent others making use of the copyright material, in the case of Crown copyright materials these rights should rarely be asserted by government to deviate from the general rule that Crown copyright materials will be available for “full and free reproduction” by the community at large.

State of Origin : Queensland Crown Leasehold - lessons from New South Wales

Throughout Australia freehold land interests are protected by statutory schemes which grant indefeasibility of title to registered interests. Queensland freehold land interests are protected by Torrens system established by the Land Title Act 1994. However, no such protection exists for Crown land interests. The extent of Queensland occupied under some form of Crown tenure, in excess of 70%, means that Queensland Crown land users are disadvantaged when compared to freehold land users. This article examines the role indefeasibility of title has in protecting interests in Crown land. A comparative analysis is undertaken between Queensland and New South Wales land management frameworks to determine whether interests in crown land are adequately protected in Queensland.

Tooth fracture risk analysis based on a new finite element dental structure models using micro-CT data

The finite element (FE) analysis is an effective method to study the strength and predict the fracture risk of endodontically-treated teeth. This paper presents a rapid method developed to generate a comprehensive tooth FE model using data retrieved from micro-computed tomography (μCT). With this method, the inhomogeneity of material properties of teeth was included into the model without dividing the tooth model into different regions. The material properties of the tooth were assumed to be related to the mineral density. The fracture risk at different tooth portions was assessed for root canal treatments. The micro-CT images of a tooth were processed by a Matlab software programme and the CT numbers were retrieved. The tooth contours were obtained with thresholding segmentation using Amira. The inner and outer surfaces of the tooth were imported into Solidworks and a three-dimensional (3D) tooth model was constructed. An assembly of the tooth model with the periodontal ligament (PDL) layer and surrounding bone was imported into ABAQUS. The material properties of the tooth were calculated from the retrieved CT numbers via ABAQUS user's subroutines. Three root canal geometries (original and two enlargements) were investigated. The proposed method in this study can generate detailed 3D finite element models of a tooth with different root canal enlargements and filling materials, and would be very useful for the assessment of the fracture risk at different tooth portions after root canal treatments.