Influence of Prosthetic Emergence Profile on Peri-Implant Marginal Bone Stability: A Comprehensive Review

The prosthetic emergence profile is a factor potentially affecting marginal bone level around dental implants. The aim of this review is to provide a comprehensive analysis of the influence of the prosthetic emergence profile on peri-implant marginal bone-level stability. The marginal bone level is an important parameter in implant dentistry, reflecting the stability of dental implants, and it is a critical indicator of long-term implant success. Minimizing marginal bone loss around dental implants is a key factor for maintaining implant function, supporting peri-implant soft tissues, and achieving predictable aesthetic outcomes. The scientific literature presents various examples of evidence on the influence of emergence angle and prosthetic designs on marginal bone loss. Several studies suggest that emergence angles exceeding 30° and convex prosthetic designs may increase the risk of peri-implantitis and bone resorption, while others find no significant correlation. Moreover, several studies demonstrated the positive influence of taper joint connections on marginal bone stability. Although the current literature remains diverse, it is essential to prioritize cleanability and minimize plaque accumulation for a successful implant-prosthetic restoration. Proper maintenance and a continuous follow-up to monitor marginal bone loss are beneficial for obtaining stable and optimal long-term results.

FT-IR analysis of the Interface between Universal Scotchbond and Oral Mucosa: a preliminary in-vitro study

BACKGROUND

The long-term success of implant therapy depends not only on proper osseointegration, but also on the healing of the epithelium and the quality of the biological seal on the abutment and on the implant neck. This study aims to evaluate the possible use of dentinal adhesives on the surface of the transmucosal path of dental implants in order to create a hermetic seal between keratinized epithelium and abutment.

METHODS

Four sections of 12 µm thickness were obtained from a sample of the oral mucosa. Scotchbond TM Universal Adhesive (3M ESPE, Seefeld, Germany) was carefully applied both to the samples and to the transmucosal path of titanium abutment (Win-Six, BioSAFin, Italy). The adhesives were polymerized. FT-IR analysis was performed on: 1) polymerized Scotchbond Universal Adhesive (3M ESPE, Seefeld, Germany); 2) the interface between the titanium abutment and the adhesive; 3) the interface between the adhesive and the mucosa; 4) the mucosa samples.

RESULTS

Comparing the spectra, it emerged that the adhesive has established chemical bonds both on titanium and on the keratinized mucosa, involving different types of chemical interactions.

CONCLUSIONS

The results of this in-vitro study are encouraging. In the future biocompatibility and comparative study with other adhesives will be required.

Epithelial Biological Response to Machined Titanium vs. PVD Zirconium-Coated Titanium: An In Vitro Study

The aim of this study was to compare the epithelial biological response to machined titanium Ti-6Al-4V grade 5 and titanium Ti-6Al-4V grade 5 coated with zirconia (ZrN) by physical vapor deposition (PVD). Human keratinocytes were cultured in six-well plates. Machined titanium TiAl4V4 grade 5 (T1) and ZrN-coated titanium TiAl4V4 grade 5 (T2) discs were placed in two different wells. The remaining two wells served as control (C). Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were performed to compare the T1 and T2 surfaces. Subsequent analyses were performed to explore the effect of T1 and T2 contact with human keratinocyte HUKE cell lines. Cell viability was evaluated using a trypan blue exclusion test and MTT assay. Cell lysates from C, T1, and T2 were Western blotted to evaluate E-cadherin and Integrin-α6β4 expression. SEM revealed that T2 was smoother and more homogeneous than T1. EDS showed homogeneous and uniform distribution of ZrN coating on T2. Cell viability analyses did not show significant differences between T1 and T2. Furthermore, E-cadherin and Integrin-α6β4 expressions of the epithelial cells cultured in T1 and T2 were similar. Therefore, titanium Ti-6Al-4V grade 5 surfaces coated with ZrN by PVD seem to be similar substrates to the uncoated surfaces for keratinocyte adhesion and proliferation.

Novel hydroxyapatite biomaterial covalently linked to raloxifene

Since raloxifene, a drug used in osteoporosis therapy, inhibits osteoclast, but not osteoblast functions, it has been suggested to improve recovery during implant surgery. The present paper describes an effective method to link raloxifene, through a covalent bond, to a nano-Hydroxyapatite-based biomaterial by interfacing with (3-aminopropyl)-Triethoxysilane as assessed by Infra Red-Fourier Transformed (IR-FT) spectroscopy and Scanning Electron Microscope (SEM). To evaluate the safety of this modified new material, the vitality of osteoblast-like cells cultured with the new biomaterial was then investigated. Raloxifene-conjugated HAbiomaterial has been shown to be a safe material easy to obtain which could be an interesting starting point for the use of a new functional biomaterial suitable in bone regeneration procedures.

Pre-Clinical Evaluation of a New Coral-Based Bone Scaffold

Coral is used worldwide for bone reconstruction. The favorable characteristics that make this material desirable for implantation are (i) osteoinduction, (ii) and osteoconduction. These proprieties have been demonstrated by in vivo studies with animal models and clinical trials over a twenty-year period. Also poly(2-hydroxyethylmethacrylate) [poly(HEMA)] is a widely used biomaterial. By using coral and poly(HEMA), a scaffold for bone reconstruction application has been recently synthesized. Cytological, histological and genetic analyses were performed to characterize this new alloplastic material. Four samples were analyzed: (a) white coral (WC), (b) red coral (RC), (c) WC plus polymer (WCP) and (d) RC plus polymer (RCP). Quantification of mitochondrial dehydrogenase activity by MTT assay was performed as indirect detector of cytotoxicity. In vivo effects were revealed by implanting corals and coral-based polymers in rabbit tibia. Samples were collected after 4 weeks and subjected to histological analysis. To evaluate the genetic response of cells to corals and coral-derived polymers an osteoblast-like cell line (i.e. MG63) was cultured in wells containing (a) medium, (b) medium plus corals and (c) medium plus two types of scaffolds (RCP or WCP). RNAs extracted from cells were retro-transcribed and hybridized on DNA 19.2K microarrays. No cytotoxicity was detected in corals and coral-based biopolymers. No inflammation or adverse effect was revealed by histological examination. By microarray analysis 154 clones were differentially expressed between RC and WC (81 up and 73 down regulated) whereas only 15 clones were repressed by the polymer. Histological evaluation not only confirmed that coral is a biocompatible material, but also that the polymer has no adverse effect. Microarray results were in agreement with cytological and histological analyses and provided further data regarding the genetic effects of RC, WC and the new polymer.

MG63 and MC3T3-E1 Osteoblastic Cell Lines Response to Raloxifene

Bone resorption in edentulous regions often results in inadequate ridge for implant osseointegration. In order to overcome this problem, the use of osteoconductive biomaterials has been proposed as a carrier for different types of pharmacological molecules. Since raloxifene, a drug used in osteoporosis therapy, inhibits the osteoclast, but not osteoblast functions, it has been suggested to improve recovery during implant surgery. The present work evaluated in vitro the effect of raloxifene on two different cell populations: the human osteoblast-like cells (MG63) and osteoblasts derived from rat calvaria (MC3T3-E1). The morpho-functional investigations carried out showed a different behavior of the two cell lines. Raloxifene showed a stimulatory effect towards MG63 cell proliferation with a significant increase in cell viability after 7 days of culture. On the contrary, MC3T3-E1 cells showed a significant reduction in cell viability, when compared with the same cells at 72 h, or with the control cell population. The predominantly proliferative effect of raloxifene on MG63 cells is partly confirmed by the reduction of alkaline phosphatase activity, an early marker of osteoblast differentiation. The different effect of raloxifene on osteoblastic population in relationship to the type and age of the cell is an issue that needs further investigation.

CD3 and CD20 Expression in Titanium vs Zirconia Peri-Implant Soft Tissues: A Human Study

The aim of this study was to investigate the presence of an inflammatory infiltrate in the peri-implant soft tissue of single-implant crowns supported by either zirconia or titanium abutments in healthy subjects. Serial sections from formalin-fixed, paraffin-embedded blocks from peri-implant mucosa of 25 patients were immunohistochemically analyzed for CD3 and CD20 lymphocyte marker expression. The results showed that levels of T cells (CD3) were higher around zirconia than titanium abutments (p<0.05). On the contrary, the levels of B cells (CD20) were found higher around titanium abutment in comparison with the zirconia abutment. These differences were statistically significant (p<0.05).

Clinical and Laboratory Changes in the Uncomplicated Course of Arthroscopic Anterior Cruciate Ligament (ACL) Reconstruction: A Prospective Observational Study in 58 Patients

Knowledge of post-operative clinical and laboratory changes in the uncomplicated course of ACL reconstruction could assist orthopaedic surgeons in making a timely diagnosis of septic arthritis. A total of 58 candidates to ACL reconstruction were enrolled in this study according to inclusion/exclusion criteria. Pre- and post-operative changes on 1st, 3rd, 7th, 15th, and 30thday were collected for skin body temperature (SBT), knee pain (KP), white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP). Post-operative joint effusion was recorded when inhibiting quadriceps contraction. The post-operative changes were compared with baseline values at each time point in the whole sample and in the subgroups of patients receiving bone-patellar-tendon-bone (BPTP) or hamstring tendon (HT) autograft. Follow-up at six month was considered adequate to rule out surgery-related septic arthritis. Mean SBT significantly increased on 1st, 3rdand 7thpost-operative day and returned to values not differing from baseline on 15thand 30thday. Median KP was significantly elevated during the first month. Joint effusion was observed on 7thpost-operative day in 52% of patients. Mean WBC count significantly increased on 1st, 7thand 15thday while no difference from baseline was observed on 3rdand 30thday. Mean ESR was significantly elevated on 1stday, increased on 3rdday and peaked on 7thday. ESR decreased on 15thand 30thday but remained significantly higher than baseline. Mean CRP significantly increased on 1stday, peaked on 3rdday and decreased on 7thday, while levels on 15thand 30thday did not differ from baseline. The SBT, KP, WBC count, ESR and CRP changes stratified in relation to the type of autograft showed the same variation trend as in the whole sample. Close clinical surveillance may be advisable when SBT, occurrence of joint effusion and CRP levels deviate from the described reference trend two weeks after surgery.