Dental implants: matters of course and controversies

Evaluation of C-Reactive Proteins Levels in Peri-Implantitis Patients

Background

To evaluate C-reactive protein (CRP) levels in peri-implantitis patients.

Material and Methods

This study comprised a total of 100 participants. Fifty participants with a confirmed clinical and radiological diagnosis of peri-implantitis formed one group. Another group of 50 volunteers who came in for a normal health checkup served as healthy controls. All the patients were recalled in the morning. Fasting venous blood samples were collected. CRP concentrations in the laboratory were determined using an auto-analyzer.

Results

In this study, there were 40 females and 60 males. Mean CRP levels among subjects of the peri-implantitis group and the control group were 0.615 and 0.201 mg/dL, respectively.

Conclusion

It was observed that mean CRP levels were higher among subjects having peri-implantitis as compared to the controls.

Investigating the impact of diameters and thread designs on the Biomechanics of short implants placed in D4 bone: a 3D finite element analysis

BACKGROUND

Dental implants emerge as a dependable and efficacious alternative for patients experiencing partial or complete tooth loss. The stability of these implants is influenced by surface topography and macro-level design. In cases where the height of the maxillary posterior region is diminished, employing short implants can prove advantageous. With the aim of examining the distribution of von Mises stress, strain, and micromovement in D4 bone quality surrounding platform-switched short implants, measuring 6 mm in length and featuring diameters ranging from 4 to 6 mm, as well as different thread designs, an in-depth finite element analysis was conducted under immediate loading conditions.

METHODOLOGY

A 3D finite element model was constructed to simulate maxillary molar crowns, incorporating an implant with a length of 6 mm and varying diameters and thread designs. The diameters utilized were 4/3.6 mm, 5/4 mm, and 6/4.8 mm, while the thread designs included buttress, square, and triangle patterns. Each model underwent analysis with a 100 N force applied in two directions: vertical and oblique, relative to the long axis of the implant. Stress, strain, and micromovement in the peri-implant region were recorded, employing the Ansys Workbench R v.18.1 software for modelling and analysis.

RESULTS

When comparing all three diameters, the wide diameter (6 mm threads) exhibited the lowest values of peri-implant von Mises stresses (3.3 MPa and 35.1 MPa), strains (194 Ɛ and 484 Ɛ), and micromovements (0.7 μm and 1.3 Ɛ) subjected to axial and non-axial loading of a 100 N force. Notably, square microthreads yielded the most favorable stress parameters among the different thread shapes, manifesting the minimum values of stress, strains, and micromovements in their vicinity.

CONCLUSION

For the treatment of atrophic ridges or in scenarios necessitating extensive surgical preparation of the implant site, a combination of short implants, wide diameters, and platform switching can be employed. In situations with reduced bone height and the requirement for an implant-supported prosthesis to replace a missing permanent maxillary molar, the utilization of wide-diameter platform-switched short implants measuring 6 mm in length, featuring a square thread design, should be taken into consideration.

Prevalence of Peri-Implant Disease in Patients with Stage III or IV Periodontitis: Results of a Long-Term Follow-Up from a Specialized Periodontal Practice

The aim of this study was to examine the conditions of implants that had been in function for 5-17 years in stage III/IV periodontitis patients of a specialized periodontal practice. There were 83 patients (43 female/40 male, mean age 64.4 (9.69) years), with a total of 213 implants, who participated in the study. Assessments included periodontal and peri-implant probing depths, bleeding and plaque scores, and a radiographic examination. Smoking habits, participation in a supportive care program (SCP), and the Implant Disease Risk Assessment (IDRA) scores were recorded. A total of 44 patients presented with stage III periodontitis, and 39 with stage IV. In all, 85% of patients had adhered to regular SCP. On an implant/patient level, peri-implant health was found in 37.1.7% (79 implants)/24.1% (20 patients), peri-implant mucositis in 58.7% (125 implants)/66.3% (55 patients), and peri-implantitis in 4.2% (9 implants)/9.6% (8 patients). IDRA scores showed 30.5% of implants at moderate and 69.5% at high risk. The present long-term analysis shows a high prevalence of peri-implant disease in patients treated for advanced periodontitis. These findings underline the challenges involved in the long-term maintenance of oral health in stage III/IV periodontitis patients restored with dental implants.

Self-Assembled Monolayers for Dental Implants

Implant-based therapy is a mature approach to recover the health conditions of patients affected by edentulism. Thousands of dental implants are placed each year since their introduction in the 80s. However, implantology faces challenges that require more research strategies such as new support therapies for a world population with a continuous increase of life expectancy, to control periodontal status and new bioactive surfaces for implants. The present review is focused on self-assembled monolayers (SAMs) for dental implant materials as a nanoscale-processing approach to modify titanium surfaces. SAMs represent an easy, accurate, and precise approach to modify surface properties. These are stable, well-defined, and well-organized organic structures that allow to control the chemical properties of the interface at the molecular scale. The ability to control the composition and properties of SAMs precisely through synthesis (i.e., the synthetic chemistry of organic compounds with a wide range of functional groups is well established and in general very simple, being commercially available), combined with the simple methods to pattern their functional groups on complex geometry appliances, makes them a good system for fundamental studies regarding the interaction between surfaces, proteins, and cells, as well as to engineering surfaces in order to develop new biomaterials.

Most medical practices are not parachutes: a citation analysis of practices felt by biomedical authors to be analogous to parachutes

BACKGROUND

In a 2003 paper in BMJ, the authors made the tongue-in-cheek observation that there are no randomized controlled trials (RCTs) of parachutes. This paper has been widely read, cited and used to argue that RCTs are impractical or unnecessary for some medical practices. We performed a study to identify and evaluate claims that a medical practice is akin to a parachute.

METHODS

Using Google Scholar, we identified all citations to the 2003 paper. We searched for claims that a specific practice was akin to a parachute. For each practice, we identified the desired outcome of the practice, and searched Google Scholar and ClinicalTrials.gov for RCTs that were conducted, ongoing, halted, planned or unpublished.

RESULTS

Of 822 articles citing the original paper, 35 (4.1%) argued that a medical practice was akin to a parachute. Eighteen of the 35 (51%) concerned mortality or live birth, and 17 (49%) concerned a lesser outcome. For 22 practices (63%), we identified 1 or more RCTs: in 6 cases (27%), the trials showed a statistically significant benefit of the practice; in 5 (23%), the trials rejected the practice; in 5 (23%), the trials had mixed results; in 2 (9%), the trials were halted; and in 4 (18%), the trials were ongoing. Effect size was calculated for 5 of the 6 practices for which RCTs gave positive results, and the absolute risk reduction ranged from 11% to 30.8%, corresponding to a number needed to treat of 3-9.

INTERPRETATION

Although there is widespread interest regarding the BMJ paper arguing that randomized trials are not necessary for practices of clear benefit, there are few analogies in medicine. Most parachute analogies in medicine are inappropriate, incorrect or misused.

Clinical and Radiographic Peri-Implant Parameters and Whole Salivary Interleukin-1β and Interleukin-6 Levels among Type-2 Diabetic and Nondiabetic Patients with and without Peri-Implantitis

OBJECTIVE

The aim was to assess the peri-implant clinical and radiographic parameters and whole salivary levels of interleukin (IL)-1β and IL-6 among type 2 diabetic and nondiabetic patients with and without peri-implantitis.

MATERIAL AND METHODS

Ninety-one implants were placed in patients without type 2 diabetes mellitus (39 patients with and 52 patients without peri-implantitis; group 1). Eighty implants were placed in patients with diabetes (35 patients with and 45 patients without peri-implantitis; group 2). Peri-implant plaque index, bleeding on probing, probing depth, and marginal bone loss were measured. Unstimulated whole saliva samples were collected and IL-1β and IL-6 levels were measured using standard techniques. p < 0.05 was considered statistically significant.

RESULTS

In group 1, plaque index (p < 0.001), bleeding on probing (p < 0.001), probing depth (p < 0.001), and whole salivary IL-1β (p < 0.001) and IL-6 (p < 0.001) levels were significantly higher in patients with peri-implantitis than in those without peri-implantitis. Plaque index, bleeding on probing, probing depth, and marginal bone loss were comparable among all of the patients in group 2. Among patients with peri-implantitis, plaque index (p < 0.001), bleeding on probing (p < 0.001), probing depth (p < 0.001), marginal bone loss (p < 0.001), and whole salivary IL-1β (p < 0.001) and IL-6 (p < 0.001) levels were significantly higher in those with diabetes than in those without diabetes.

CONCLUSION

Among individuals without diabetes, peri-implant plaque index, bleeding on probing, probing depth, marginal bone loss, and whole salivary IL-1 β and IL-6 levels were higher among patients with peri-implantitis compared to patients without peri-implantitis. Among patients with diabetes, the severity of the measured parameters appears to be influenced by the glycemic status rather than by peri-implantitis.

Isotropic micropatterned silica coatings on zirconia induce guided cell growth for dental implants

Titanium implants are the gold standard in dentistry; however, problems such as gingival tarnishing and peri-implantitis have been reported. For zirconia to become a competitive alternative dental implant material, surface modification techniques that induce guided tissue growth must be developed.

OBJECTIVES

To develop alternative surface modification techniques to promote guided tissue regeneration on zirconia materials, for applications in dental implantology.

METHODS

A methodology that combined soft lithography and sol-gel chemistry was used to obtain isotropic micropatterned silica coatings on yttria-stabilized zirconia substrates. The materials were characterized via chemical, structural, surface morphology approaches. In vitro biological behavior was evaluated in terms of early adhesion and viability/metabolic activity of human osteoblast-like cells. Statistical analysis was conducted using one-way ANOVA/Tukey HSD post hoc test.

RESULTS

Isotropic micropatterned silica coatings on yttria-stabilized zirconia substrates were obtained using a combined approach based on sol-gel technology and soft lithography. Micropatterned silica surfaces exhibited a biocompatible behavior, and modulated cell responses (i.e. inducing early alignment of osteoblast-like cells). After 7d of culture, the cells fully covered the top surfaces of pillar microstructured silica films.

SIGNIFICANCE

The micropatterned silica films on zirconia showed a biocompatible response, and were capable of inducing guided osteoblastic cell adhesion, spreading and propagation. The results herein presented suggest that surface-modified ceramic implants via soft lithography and sol-gel chemistry could potentially be used to guide periodontal tissue regeneration, thus promoting tight tissue apposition, and avoiding gingival retraction and peri-implantitis.

Early spreading and propagation of human bone marrow stem cells on isotropic and anisotropic topographies of silica thin films produced via microstamping

While there has been rapid development of microfabrication techniques to produce high-resolution surface modifications on a variety of materials in the last decade, there is still a strong need to produce novel alternatives to induce guided tissue regeneration on dental implants. High-resolution microscopy provides qualitative and quantitative techniques to study cellular guidance in the first stages of cell-material interactions. The purposes of this work were (1) to produce and characterize the surface topography of isotropic and anisotropic microfabricated silica thin films obtained by sol-gel processing, and (2) to compare the in vitro biological behavior of human bone marrow stem cells on these surfaces at early stages of adhesion and propagation. The results confirmed that a microstamping technique can be used to produce isotropic and anisotropic micropatterned silica coatings. Atomic force microscopy analysis was an adequate methodology to study in the same specimen the sintering derived contraction of the microfabricated coatings, using images obtained before and after thermal cycle. Hard micropatterned coatings induced a modulation in the early and late adhesion stages of cell-material and cell-cell interactions in a geometry-dependent manner (i.e., isotropic versus anisotropic), as it was clearly determined, using scanning electron and fluorescence microscopies.

A 4- to 5-year retrospective clinical and radiographic study of Neoss implants placed with or without GBR procedures

BACKGROUND

New dental implant systems are continuously introduced to the market. It is important that clinicians report their experiences with these implants when used in different situations.

AIM

The study aims to report the outcomes from a retrospective study on Neoss implants when used with or without guided bone regeneration (GBR) procedures.

MATERIALS AND METHODS

The study group comprised of 50 consecutive patients previously treated with 183 Neoss implants (Neoss Ltd., Harrogate, UK) in 53 sites because of single, partial, or total tooth loss. Implants were placed in healed bone in 23 sites, while a GBR procedure was used in 30 sites in conjunction with implant placement. A healing period of 3 to 6 months was utilized in 45 sites and in 8 sites a crown/bridge was fitted within a few days for immediate/early function. The number of failures, withdrawn and dropout implants was analyzed in a life-table. All available intraoral radiographs from baseline and annual check-ups were analyzed with regard to marginal bone level and bone loss.

RESULTS

A cumulative survival rate (CSR) of 98.2% was found for the non-GBR group and 93.5% for the GBR group with an overall CSR of 95.0% after up to 5 years of loading. In spite of the failures, all patients received and maintained their prostheses. Based on all available radiographs, the bone level was situated 1.3±0.8mm (n=159) below the top of the collar at baseline and 1.7±0.8mm (n=60) after 5 years of follow-up. Based on paired baseline and 1-year (n=70) and 5-year radiographs (n=59), the bone loss was found to be 0.4±0.9 and 0.4±0.9mm, respectively. There were no statistically significant differences between GBR and non-GBR sites with regard to implant survival or bone loss.

CONCLUSIONS

The Neoss implant system showed good clinical and radiographic results after up to 5 years in function.

Fixed rehabilitation of the edentulous maxilla: possibilities and clinical outcome

PURPOSE

The aim of the present report was to describe the different treatment approaches available for fixed rehabilitation of the edentulous maxilla in the presence of varying hard and soft tissue conditions and to review the clinical outcome of each treatment approach.

MATERIALS AND METHODS

A review of the published data published from 1980 through 2009 was conducted using electronic databases and manual searching to identify the treatment possibilities for the fixed rehabilitation of the edentulous maxilla and report their clinical outcomes. The search terms used, in simple or multiple conjunctions, were "fixed rehabilitation," "implants," "edentulous," "fixed dental prosthesis," "implant-supported," and "maxilla."

RESULTS

Several treatment modalities were identified for the fixed rehabilitation of the edentulous maxilla, with and without bone augmentation procedures. Regular, tilted, and zygoma implants were identified for treatment modalities that do not require bone augmentation. Sinus floor elevation with the lateral window technique or Le Fort I osteotomy with interpositional bone grafts was identified as a treatment possibility that required bone augmentation procedures. The database initially yielded 230 titles. Of the 230 studies, 42 were finally selected. Although all studies reported the survival rates of the implants, only 20 provided information about the prosthetic outcome. Because of the limited number of studies, at least for the specific treatment modalities, and the heterogeneity in the design of the different studies identified, it was not possible to perform a statistical analysis of the data. Except for regular implants placed in native bone, no sufficient long-term clinical studies were found for the other procedures.

CONCLUSIONS

Except for regular implants placed in nonaugmented native bone, the published data provide insufficient evidence about the outcome of other procedures. Until long-term data are available, such procedures should not be considered reliable treatment modalities.