Ghadeer Thalji

Comparative molecular assessment of early osseointegration in implant-adherent cells

OBJECTIVE The objective of our study is to identify the early molecular processes involved in osseointegration associated with a micro roughened and nanosurface superimposed featured implants. MATERIALS AND METHODS Thirty-two titanium implants with surface topographies exhibiting a micro roughened (AT-II) and nanosurface superimposed featured implants (AT-I) were placed in the tibiae of 8 rats and subsequently harvested at 2 and 4 days after placement. Total RNA was isolated from cells adherent to retrieved implants. A whole genome microarray using the Affymetrix Rat Gene 1.1 ST Array followed by validation of select genes through qRT-PCR was used to describe the gene expression profiles that were differentially regulated by the implant surfaces. RESULTS While significant differences at the gene level were not noted when comparing the two-implant surfaces at each time point, the microarray identified several genes that were differentially regulated at day 4 vs. day 2 for both implant surfaces. A total of 649 genes were differentially regulated at day 4 vs. day 2 in AT-I and 392 genes in AT-II implants. Functionally relevant categories related to ossification, skeletal system development, osteoblast differentiation, bone development, bone mineralization and biomineral tissue development were upregulated and more prominent at AT-I (day 4 vs. day 2) compared to AT-II. Analysis of the downregulated gene lists (day 4 vs. day 2) with average fold change >2 (were not statistically significant) revealed the biological processes involved with the inflammatory/immune response gene expression. The number of genes that were associated with the inflammatory/immune response category was greater for AT-I than AT-II. CONCLUSIONS The presence of nanosurface features modulated in vivo bone response. Gene regulation implicating osteogenesis as well as the inflammatory/immune responses that occur as a function of surface topography may affect bone mass shortly after implant placement.

Molecular assessment of osseointegration in vivo: a review of the current literature.

This paper presents the results of a structured review of the literature concerning in vitro molecular assessment of osseointegration at the level of cell-surface topography interactions. A search of the electronic databases was performed up to and including November 2010, with 320 articles meeting the inclusion criteria. Characteristics of the included in vitro reports were model systems used, genes examined, techniques used for molecular assessment of the osseointegration process, and wide gene expression profiling studies. There exists a growing body of in vitro evidence to support a role for surface topography in the direct influence of cellular phenotypes as related to the process of osseointegration. Most recently, functional or mechanistic studies have provided evidence that particular topographic cues can be specifically integrated among the many extracellular signals received by the cell in its signal transduction network. Such investigations begin to define linkages between the character of the implant surface and adherent cellular responses, including cells from extravasated blood (eg, platelets) and of the immune system (eg, monocytes). In vitro studies involving cell culture on endosseous implant-related biomaterials offer important and beneficial insight into the clinical control of the implant-bone interface.

Radiographic stents: integrating treatment planning and implant placement.

The pivotal point in treatment planning for dental implants occurs when the location of bone is viewed radiographically in the context of the planned prosthesis. Radiographic planning for dental implant therapy should be used only after a review of the patients systemic health, imaging history, oral health, and local oral conditions. The radiological diagnostic and planning procedure for dental implants can only be fully achieved with the use of a well-designed and -constructed radiographic guide. This article reviews several methods for construction of radiographic guides and how they may be utilized for improving implant surgery planning and performance.

Prosthodontic Management of Implant Therapy

Implant-supported dental restorations can be screw-retained, cement-retained, or a combination of both, whereby a metal superstructure is screwed to the implants and crowns are individually cemented to the metal frame. Each treatment modality has advantages and disadvantages. The use of computer-aided design/computer-assisted manufacture technologies for the manufacture of implant superstructures has proved to be advantageous in the quality of materials, precision of the milled superstructures, and passive fit. Maintenance and recall evaluations are an essential component of implant therapy. The longevity of implant restorations is limited by their biological and prosthetic maintenance requirements.

Implant‐Supported Fixed Dental Rehabilitation with Monolithic Zirconia: A Clinical Case Report

OBJECTIVE Veneer chipping in bilayered ceramic restorations is a current problem reported with significant frequency. CLINICAL CONSIDERATIONS This clinical report describes the use of a monolithic, implant-supported restoration with gingiva-colored ceramics. Good esthetic and functional results were achieved with no complications reported after 3 years. CONCLUSIONS Prosthetic rehabilitation using monolithic zirconia may help to prevent complications associated with bilayered ceramics systems. Further studies are essential to provide long-term data about the performance of this type of prostheses.

The role of complete overdentures in esthetic rehabilitation of the adolescent oligodontia patient. A case report

STATEMENT OF THE PROBLEM Dental agenesis is a common developmental anomaly among human populations. It presents with varying degrees of severity. Oligodontia present in the permanent dentition may have significant esthetic, psychosocial, as well as functional implications. CASE PRESENTATION A case of oligodontia in an adolescent patient treated with conventional overdentures is presented in this article. A thorough medical and dental history were taken. Comprehensive clinical and radiographic examinations were made. Diagnostic casts were mounted. The prosthetic denture teeth were set and followed by esthetic and phonetic evaluation. Following approval by the patient, the overdentures were processed in heat cure resin using the conventional techniques. RESULTS Good esthetic results were achieved. Patient was satisfied with the final prostheses. CONCLUSION Simple prosthodontic solutions can be utilized to aid patients with dental agenesis. These have great implications for the patients self image. CLINICAL SIGNIFICANCE Oligodontias are common. The literature frequently addresses esthetic rehabilitation using fixed prostheses and dental implants. This case report illustrates the value of removable prosthodontic procedures as one approach to fulfilling the requirements of esthetic rehabilitation of a young oligodontia patient.

Gene Expression Profiles of Early Implant Adherent Cells in Smokers and Nonsmokers

The objective of this study was to evaluate the impact of smoking on the early molecular events involved in peri-implant healing at either a micro-roughened or a micro-roughened with superimposed nanofeatures surface implant in humans. Twenty-one subjects, 10 smokers and 11 nonsmokers received 4 mini-implants (2.2 × 5.0 mm; 2 of each surface). After 3 and 7 days, paired mini-implants were retrieved by reverse threading and RNA isolated from implant adherent cells. Whole genome microarrays were used interrogate the gene expression profiles. The study failed to identify differences in the gene expression profiles of implant adherent cells at this early stage of osseointegration (up to day 7) comparing smoker and nonsmoker individuals.

Patient Selection and Treatment Planning for Implant Restorations

Dental implants are an indispensible tool for the restoration of missing teeth. Their use has elevated the practice of dentistry by improving both our technical ability to rehabilitate patients and general quality of life. To routinely achieve the associated high expectations, diligent attention to details must be observed and addressed from the outset. Of central concern is the attainment of osseointegration and the location of implants to ideally support the intended restoration. The pivotal point in treatment planning for dental implants occurs when the location of bone is viewed radiographically in the context of the planned prosthesis. This most often requires diagnostic waxing or tooth arrangement using mounted diagnostic casts.