Medical Contraindications to Implant Therapy: Part II: Relative Contraindications

Does strontium coated titanium implants enhance the osseointegration in animal models under osteoporotic condition? A systematic review and meta-analysis

PURPOSE

The aim of this study was to systematically review the literature to address the effect of strontium modified titanium implants on the osseointegration in the presence of osteoporotic conditions through animal models.

MATERIALS AND METHODS

The databases (PubMed, Scopus, Web of Science, and EBSCO) were searched electronically, and manual searches were performed till December 2022 to identify preclinical studies on the osseointegration of strontium coated titanium implants in animals with induced osteoporotic conditions. The primary outcomes were the bone-implant contact percentage (BIC%), bone area (BA) from the histomorphometric analysis, and the osseointegration parameters from biomechanical tests; the secondary outcomes were the osseointegration parameters from the micro computed tomography.

RESULTS

Nineteen articles were included for the quantitative analysis on basis of the inclusion criteria. The results revealed that Sr-modified implants showed a significant 19.05% increase in BIC, and 15.01% increase in BA. The results of biomechanical tests indicated a significant effect in favor of Sr-coated implants. Furthermore, Results of the secondary outcomes supported the significant advantages of Sr-coated implants over the un-coated implants. The overall, systematic analysis of implants osteointegration parameters proved a significant increase in favor of Sr-coated titanium implants (P < 0.01).

CONCLUSION

The present results provide evidence that strontium-coated titanium implants enhanced the osseointegration in animal models under osteoporotic condition as this surface modification techniques have improved the mechanical and biological properties of the titanium implants.

Dental Implant Placement in Medically Compromised Patients: A Literature Review

As a discipline of dentistry, oral implantology deals with the diagnosis, design, insertion, restoration, and/or management of alloplastic or autogenous oral structures for the purpose of regaining contour, function, aesthetics, and speech in a partially or completely edentulous patient. The present review aims to provide the currently available knowledge about the impact of certain systemic disorders and the usage of some medications on the survival rate of dental implant therapy and to highlight the importance of patient management under these conditions. Diabetes, osteoporosis, cardiovascular diseases, and the intake of some medications can increase the risk of the failure of a dental implant. Even though there are relatively few medical contraindications to dental implant treatment, certain conditions may increase the risk of failure or complications.

Efficacy and safety of using antibiotics to prevent post-operative complications in oral implant treatment: evidence-based review

AIMS

To identify and critically appraise available evidence on the efficacy and safety of antibiotics in preventing complications following oral implant placement treatment.

METHODS

An electronic search was performed using PubMed, Ovid MEDLINE and Cochrane Library databases up to July/21 for the purpose of answering the research question: In[healthy adults treated with dental implants]the use of[different antibiotics before or immediately after treatment]in comparison to[treatment without antibiotics]is safe and effective in terms of[infection, pain, swelling, wound dehiscence, soft tissue healing, early/late implant failure]? Following the Best Evidence Topic methodology, the included studies were categorised based on the Oxford Centre for Evidence-Based Medicine (OCEBM) ratings. The critical appraisal skills programme CASP checklist was used for the methodological analysis. The risk of bias assessment was performed according to the Cochrane Methodology for Systematic Reviews of Interventions.

RESULTS

26 of the 245 initially identified articles met our inclusion criteria for analysis after applying rigorous filters. The included human studies demonstrated significant methodological heterogeneity, precluding meta-analysis. These studies spanned evidence levels II to IV, as per OCEBM 2011 classifications, with the United States contributing the most studies (19.2%, n = 5), all at level III. The United Kingdom and Spain followed with three studies each (11.5% each), two from the UK and one from Spain classified at level II. Most studies had less than 1 year of follow-up (21%). Our analysis included 26 studies, with 38 antibiotic patient groups totalling 7459 patients. Amoxicillin was the predominant antibiotic, with various dosage regimens. Complications were observed in studies across different amoxicillin regimens at a cumulative incidence of 5%.

CONCLUSION

The evidence on antibiotics to prevent implant failure presents uncertain and heterogeneous findings. High-risk bias and underpowered studies were prevalent. Future research should prioritise multicentre, double-blinded RCTs with larger samples and longer follow-ups. Structured methodologies, antibiotic stewardship, and adherence to guidelines are needed. Amoxicillin (2 g) was commonly prescribed, but guidelines recommend 3 g, which results in relatively low complications yet there is limited evidence to support it. Clindamycin was favoured for penicillin allergies, but caution is advised due to potential implant failure risk. Consistent use of antiseptic mouthwash was observed. Future research should explore alternatives to antibiotics and antibiotic stewardship. Establishing a well-funded research consortium could yield conclusive results for clinical practice.

Regeneration of Buccal Wall Defects after Tooth Extraction with Biphasic Calcium Phosphate in Injectable Form vs. Bovine Xenograft: A Randomized Controlled Clinical Trial

Bone healing after tooth extraction may be affected by defects of the alveolus buccal wall, such as fenestrations and dehiscences. Therefore, to minimize dimensional changes it is advisable to perform alveolar ridge preservation after tooth extractions. Different biomaterials are used for this purpose. The aim of this study was to investigate the qualitative and quantitative histological changes in human biopsies taken after 6 months of healing of extraction sockets with buccal wall defects. For this purpose, the defects of 36 patients (18 per group) were treated with injectable biphasic calcium phosphate (I-BCP) or bovine xenograft (BX) after extraction. After six months of healing, biopsies were taken and proceeded to the histology laboratory. No evidence of an inflammatory response of the tissue was observed in the biopsies of either group, and the newly formed bone (NB) was in close contact with the remaining biomaterial (BM). The histomorphometric results showed that there was no statistically significant difference between the groups in the mean percentage of NB (p = 0.854), BM (p = 0.129), and soft tissue (p = 0.094). To conclude, both biomaterials exhibited osteoconductivity and biocompatibility and achieved satisfactory bone regeneration of buccal wall defects after tooth extraction.

Avoiding implant-related complications in medically compromised patients with or without unhealthy lifestyle/Elevated oxidative stress

Increased human life expectancy broadens the alternatives for missing teeth and played a role in the widespread use of dental implants and related augmentation procedures for the aging population. Though, many of these patients may have one or more diseases. These systemic conditions may directly lead to surgical complications, compromise implant/bone healing, or influence long-term peri-implant health and its response to biologic nuisances. Offering patients credible expectations regarding intra- and postoperative complications and therapeutic prognosis is an ethical and legal obligation. Clear identification of potential types of adverse effects, complications, or errors is important for decision-making processes as they may be related to different local, systemic, and technical aspects. Therefore, the present review structures the underlying biological mechanisms, clinical evidence, and clinical recommendations for the most common systemic risk factors for implant-related complications.

Evaluation of trephine osteotomy technique in direct sinus lifting with simultaneous implant placement

BACKGROUND

Recently, in implant dentistry, trephine drills have been used instead of conventional drills to conserve the bone during osteotomy.

AIM OF THE STUDY

To evaluate the effectiveness of trephine osteotomy for lateral sinus lifting technique associated with sinus floor augmentation using the autogenous bone resulting from implant drilling using specialized trephine drills.

MATERIALS AND METHOD

12 Patients were included and have been subjected to lateral sinus lifting using trephine osteotomy with simultaneous implant placement with delay loading. A bone graft used in sinus floor augmentation has been prepared using autogenous bone resulting from implant site preparation in addition to β-tricalcium phosphate.

RESULTS

After 6 months, the difference between the primary stability and implant stability was statistically significant p-value ≤ 0.05. After 6 months, the mean vertical bone height reached 11.71 ± 0.72 mm. The mean volume of the newly formed bone of the grafted area recorded after 6 months was 1126.7 ± 82.94 mm³.

CONCLUSION

Trephine osteotomy technique in both lateral approach of sinus lifting, and implant site preparation allows preservation of autogenous bone. Moreover, the trephine osteotomy technique in the lateral approach of sinus lifting eliminates the use of an absorbable membrane.

Dental implant failure and factors associated with treatment outcome: A retrospective study

PURPOSE

The purpose of the present study was to retrospectively 1) investigate the association between implant-, patient- and bone-related parameters with the risk of implant failure; 2) analyze the survival rates of dental implants placed in a university clinical setting.

METHODS

Data were retrieved from patient charts from the University of Minnesota School of Dentistry to identify patients older than 18 years of age who received dental implant treatment by faculty, residents or students in the university dental clinics. Implant-, patient- and bone-related parameters such as implant system, length, diameter, jaw, region, installation protocol, gender, smoking, medical history, history of periodontal disease, self-reported oral parafunctions, type of bone, and operator were manually retrieved and analyzed.

RESULTS

Five hundred and fifty-three implants were randomly selected from a total of 4,424. Of these 553 implants, 440 (79.6%) were associated with a >10 mm length, 371 (67.1%) with a >4 mm diameter and 431 (77.9%) had replaced a single tooth. Submerged healing mode was followed in 363 (65.6%) of the implants with the mean healing time being 3.2 months. History of periodontal disease was identified in 294 (53.2%) of these cases. A total of 17 implants failed after a mean time of 6.29 ± 6.75 months, resulting in an overall survival rate of 96.9%. Based on a univariate analysis, implant system, operator, time between extraction and implant surgery, time between bone grafting and implant placement, tobacco use as well as clenching and grinding were considered potential implant failure predictors and were further included in the multivariate logistic regression analysis. Tobacco use (p < 0.001) was significantly associated with implant failure.

CONCLUSION

Within the limitations of this retrospective randomly selected university-treated sample tobacco use increased the risk for implant failure. Failure occurred in 17 implants representing a 3.1% failure rate.

Survival Rates and Factors Affecting the Outcome Following Immediate and Delayed Implant Placement: A Retrospective Study

Background: Immediate implant placement into extraction sockets has become a widely acceptable treatment option to decrease treatment time and enhance esthetics. The objectives of this study were to assess and compare the survival rates of immediate and delayed implant treatment as well as to investigate the effect of patient- and site-related variables on the treatment outcome in a large-scale population-based study. Methods: Dental records of patients who received implant therapy were retrieved from the electronic records of the University of Minnesota School of Dentistry. Demographic characteristics, dental insurance status, socioeconomic status as well as medical history and tobacco use were recorded. The treatment outcome was included as a binary variable (survival/failure). Time to failure (date of procedure to date of visit with failure) was compared between immediate and delayed implant treatment in Cox regression models. Kaplan−Meier plots for the survival of both treatment modalities were created. Patient-sites without failure were censored at the last follow-up visit. Results: A total of 4519 records of implants were included. The sample mean age was 60.27 years and included 50.7% males and 12.9% tobacco users. High socioeconomic status was characterized for 82.3% of the included population and 63.0% of them were self-payers. Immediate implants were significantly more frequently placed in the maxillary arch (p < 0.001) than in the mandible. Tobacco users received more often a delayed rather than an immediate implant placement (p = 0.001). The survival rate analysis revealed there were no significant differences between immediate and delayed implant placements (p = 0.48). The mean follow-up time was 32.27 months during which 1.5% immediate and 1.1% delayed implants were removed. The estimated mean survival time for immediate implants was 68.90 months, while delayed implants placed in healed sockets showed a mean survival time of 75.11 months. A statistically significant association was found between gender (p = 0.03) and osteoporosis (p = 0.001) with treatment outcome. Conclusions: The placement of immediate implants achieved similarly high survival rates when compared to delayed implants placed in healed sites. Males and osteoporotic individuals showed significantly higher implant failure than females and non-osteoporotic patients. This study demonstrated that both immediate and delayed implant placements are sound options with predictable treatment outcome.

Narrow diameter implants to replace congenital missing maxillary lateral incisors: a 1-year prospective, controlled, clinical study

OBJECTIVES

To report the clinical, radiographic, aesthetic and patient-reported outcomes after placement of a newly developed Narrow-Diameter Implant (NDI) in patients with congenitally Missing Lateral Incisors (MLIs).

MATERIALS AND METHODS

Patients with MLIs with a mesio-distal distance between the canine and the central incisor of 5.9-6.3mm received a dental implant with a diameter of 2.9mm (Test), while a diameter of 3.3mm (Control) was used when the distance was 6.4-7.1mm. After healing, a cement-retained bi-layered zirconia crown was fabricated. At the 1-year follow-up (T2), implant survival rate, marginal Crestal Bone Level (CBL) changes, biological and technical complications were registered. The aesthetic outcome was assessed by using the Copenhagen Index Score, and the patient-reported outcomes were recorded using the OHIP-49 questionnaire.

RESULTS

One-hundred patients rehabilitated with 100 dental implants Ø2.9mm (n = 50) or Ø3.3mm (n = 50) were included. One Ø3.3mm implant was lost and 7 patients dropped out of the study, yielding an implant survival rate of 99% (p = 1.000). At T2 a CBL of -0.19 ± 0.25 mm (Test) and -0.25 ± 0.31 mm (Control) was detected, with no statistically significant difference between the groups (p = 0.342). Good to excellent aesthetic scores (i.e. 1-2) were recorded in most of cases. Technical complications (i.e. loss of retention, abutment fracture, chipping of veneering ceramic) occurred once in three patients with no statistically significant difference between the groups (p > 0.05). OHIP scores did not differ significantly at follow-ups between groups (p = 0.110).

CONCLUSION

The use of Ø2.9mm diameter implants represents as reliable a treatment option as Ø3.3mm implants, in terms of CBL changes, biological and technical complications. Favorable aesthetics and patient-reported outcomes were recorded for both groups.

Comparison of Injectable Biphasic Calcium Phosphate and a Bovine Xenograft in Socket Preservation: Qualitative and Quantitative Histologic Study in Humans

This study is the first histologic evaluation of an injectable biphasic calcium phosphate (IBCP) in humans six months after socket preservation according to the principles of guided bone regeneration. After tooth extraction, the alveolar ridge of 21 patients was augmented with IBCP (maxresorb® inject) in the test group, while 20 patients in the control group received a bovine xenograft (BX) (cerabone®). Six months after augmentation, a reentry procedure was performed to collect biopsies of regenerated bone for qualitative and quantitative histologic analysis. A total of 20 biopsies were taken for analysis. Qualitative histologic analysis showed complete integration of the biomaterial and no inflammatory tissue reaction, indicating the biocompatibility of the bone grafts and the surrounding tissue in both groups. Histomorphometric analysis showed comparable results in terms of newly formed bone (IBCP: 26.47 ± 14.71%, BX: 30.47 ± 16.39%) and residual biomaterial (IBCP: 13.1 ± 14.07%, BX: 17.89 ± 11.81%), with no significant difference found across groups (p > 0.05, Mann—Whitney U test). Statistical significance between groups was found in the result of soft tissue percentage (IBCP: 60.43 ± 12.73%, BX: 51.64 ± 14.63%, p = 0.046, Mann—Whitney U test). To conclude, IBCP and BX showed good osteoconductivity and biocompatibility with comparable new bone formation six months after alveolar ridge preservation.

Dental implants in individuals living with HIV-1: Results from a prospective study in patients undergoing highly active antiretroviral therapy

OBJECTIVE

To assess survival and success rates of dental implants and the occurrence of peri-implant diseases (mucositis/peri-implantitis) in HIV-1-infected individuals.

MATERIAL AND METHODS

In this prospective study, 13 HIV-1-infected individuals undergoing highly active antiretroviral therapy (with undetectable plasma HIV RNA levels, and CD4+ T cells > 350/mm³ ) were followed after implant placement, as well as 13 non-HIV-1-infected matched controls. Patients enrolled in this study were followed up to 120 months (mean = 40.6 months; standard deviation = 22.2; range 18 -120 months). Twenty-five implants were placed in pristine healed sites for each group and bone augmentation procedures, when needed, were done only for contour augmentation. Patients were enrolled in a strict periodontal/peri-implant supportive therapy protocol with three recalls per year. The two groups were compared regarding subject-level characteristics (age, gender, smoking, diabetes) and implant-level characteristics (marginal bone level, peri-implant health status).

RESULTS

All the implants healed uneventfully and reached 100% survival rates (after at least 18 months) in both groups. There were no significant differences between groups for peri-implant diseases (mucositis/peri-implantitis) and for all subject-level co-variables (p > .05). Only the variables dental implant prosthesis type (DIPT) (p = .021, d = .86) and follow up (p = .011, d = .77) showed statistically significant differences between groups.

CONCLUSION

The findings suggest that well-controlled HIV-1-infected individuals are eligible to undergo implant therapy, achieving survival and success rates comparable to non-HIV-1-infected controls.

Association of interleukin-1 gene polymorphism and early crestal bone loss around submerged dental implants: A systematic review and meta-analysis

Aim:

Early crestal bone loss (ECBL) has been observed regardless of the absence of possible etiologic factors for bone loss during the healing phase and before the second-stage implant surgery. The purpose of this systematic review and meta-analysis was to correlate the possible association of interleukin-1 (IL-1) gene polymorphisms and ECBL (bone loss before the second-stage surgery) around dental implants.

Settings and Design:

Systematic review and meta-analysis following PRISMA guidelines.

Materials and Methods:

Considering the inclusion criteria, an electronic search by using specific keywords of three databases PubMed [(“Dental” OR “oral”) AND (“Implants*”) AND (“gene polymorphism” OR “genotype” AND (“IL-1” OR “interleukins”)], Cochrane library [implant AND (biomarker or cytokine), interleukin-1 or IL-1 AND implants], and EMBASE [(“gene polymorphisms”/de OR “interleukins”/cytokine exp OR “biomarker”:ti,ab,kw) AND (“dental implantation”/de OR “oral implant”)] and manual search from 1995 till March 2020 was made by 2 independently calibrated reviewers. ACROBAT-NRSI, Version 1.0.0 and Review Manager, Version 5.3, computer software were used for the risk of bias assessment and to conduct the meta-analysis respectively.

Statistical Analysis Used:

Cochran's Q test and I² statistics.

Results:

Of 38 articles which were found eligible for full-text screening, two articles fulfilled the inclusion criteria and hence were included in the meta-analysis. The I² statistic and Q-test values of the included studies revealed acceptable homogeneity for studied three IL-1 gene polymorphisms (IL-1A−889: I² =0%, IL-1B − 511: I² = 0%, IL-1B+3954: I² = 24%). Forest plot of association between IL-1B−511 gene and ECBL revealed a significant association between 2/2 genotype of IL-1B−511 gene and an increased risk of ECBL (OR = 0.23, 95% CI = 0.09–0.58, P_{heterogeneity}= 0.68, I² = 0%, and P = 0.002). Results of the IL-1A−889 and IL-1B+3954 gene revealed no significant associations between any genotype of these genes with risk of ECBL.

Conclusions:

There is an evidence of the association of IL-1B−511 (2/2) genetic polymorphisms and increased ECBL in the individuals of Asian ethnicity (OR = 0.23, P = 0.002).

Need for lateral bone augmentation at two narrow-diameter implants: A prospective, controlled, clinical study

OBJECTIVES

To detect the potential influence of implant diameter and anatomic factors on the need for bone augmentation procedures (BAPs) when replacing congenitally missing lateral incisors (MLIs).

MATERIALS AND METHODS

Patients with congenitally missing MLIs with a mesio-distal distance between the canine and the central incisor of 5.9-6.3 mm received a Ø2.9 mm implant while Ø3.3 mm implants were placed when the distance was 6.4-7.1 mm. The following linear measurements were recorded using a calliper: width of the alveolar process (WAP), width of the bony alveolar ridge (WAR) and thickness of the facial bone after implant osteotomy (TFB). Guided bone regeneration was performed in case of fenestration- or dehiscence-type defects or a thin TFB (<1.7 mm).

RESULTS

Fifty Ø2.9 mm and 50 Ø3.3 mm were included in 100 patients. WAP and WAR did not differ between the groups (p > .05). TFB was statistically significant larger in the Ø2.9 group (1.75 ± 0.59 mm) compared to the Ø3.3 group (1.5 ± 0.63 mm) (p = .041). Fenestration-type defects (p = .005) and a thin facial bone wall (p = .045) was observed more frequently in the Ø3.3 compared to the Ø2.9 group. Correspondingly, BAP was indicated more frequently in the Ø3.3 compared to the Ø2.9 group (p = .017). WAP, MD and WAR were statistically significant correlated to the need for BAP (p < .001). As independent variable, only WAR influenced the probability of BAP (p < .001).

CONCLUSION

The use of 2.9 diameter implants was correlated to a reduced frequency of BAP compared to 3.3 mm implants, without reaching a statistically significant difference. Measurement of the WAP provides the clinician useful information to predict BAP.

Parathyroid hormone (1-34) can reverse the negative effect of valproic acid on the osseointegration of titanium rods in ovariectomized rats

Objective

The present work was aimed to evaluate the effect of valproic acid (VPA)，Parathyroid hormone (1–34) (PTH)+VPA on Ti rods osseointegration in ovariectomized rats and further investigation of the possible mechanism.

Methods

The MC3T3-E1 cells were co-cultured with VPA，PTH ​+ ​VPA and induced to osteogenesis, and the cell viability，mineralization ability were observed by MTT and ALP staining，Alizarin Red staining and Western blotting. Twelve weeks after bilateral ovariectomy, all animals were randomly divided into four groups: group OVX and VPA，PTH ​+ ​VPA, and all the rats received Ti implants and animals belong to group VPA，PTH ​+ ​VPA received valproic acid (300 ​mg/day), valproic acid (300 ​mg/day) plus Parathyroid hormone (1–34) every 3 days (60 ​μg/kg), respectively, treatment until death at 12 weeks. Micro-CT, histology, biomechanical testing, bone metabolism index and Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis were used to observe the therapeutic effect and explore the possible mechanism.

Results

Results shown that VPA decreased new bone formation around the surface of titanium rods and push-out force other than group OVX. Histology, Micro-CT and biochemical analysis results showed combined application of systemic VPA showed harmful effects than OVX group on bone formation in osteopenia rats, with the worse effects on CTX-1, P1NP and microarchitecture as well as biomechanical parameters by down-regulated gene expression of Runx2, OCN, Smad1, BMP-2 and OPG, while up-regulated RANKL. However, after PTH treatment, the above indicators were significantly improved.

Conclusions

The present study suggests that systemic use of VPA may bring harm to the stability of titanium implants in osteoporosis, PTH can reverse the negative effect of VPA on the osseointegration of titanium rods in ovariectomized rats.

Translational potential of this article

According to our research, when patients with epilepsy have osteoporotic fractures, after joint replacement or internal fixation, continue to use sodium valproate for anti-epileptic therapy, the possibility of postoperative loosening increases, again on the basis of It can be reversed with the anti-osteoporosis drug parathyroid hormone (1-34).

Simvastatin can enhance the osseointegration of titanium rods in ovariectomized rats maintenance treatment with valproic acid

The present work was aimed to evaluate the effect of valproic acid(VPA), simvastatin (SIM)+VPA on Ti(titanium) rods osseointegration in ovariectomized(OVX) rats and further investigation of the possible mechanism. The MC3T3-E1 cells were co-cultured with VPA, SIM + VPA and induced to osteogenesis, and the cell viability, mineralization ability were observed by MTT and ALP staining, Alizarin Red staining and Western blotting. Twelve weeks after bilateral ovariectomy, all animals were randomly divided into three groups: group OVX and VPA, SIM + VPA, and all the rats received Ti implants and animals belong to group VPA, SIM + VPA received valproic acid(300 mg/kg/day), valproic acid(300 mg/kg/day) plus SIM (25 mg/kg/day), respectively, treatment until death at 12 weeks. Micro-CT, histology, biomechanical testing, bone metabolism index and Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis were used to observe the therapeutic effect and explore the possible mechanism. Results shown that VPA decreased new bone formation around the surface of titanium rods and push-out force other than group OVX. Histology, Micro-CT and biochemical analysis results showed combined application of systemic VPA showed harmful effects than OVX group on bone formation in osteopenic rats, with the worse effects on CTX-1, P1NP and microarchitecture as well as biomechanical parameters by down-regulated gene expression of Runx2, OCN, Smad1, BMP-2 and OPG, while up-regulated RANKL. However, after SIM treatment, the above indicators were significantly improved. The present study suggests that systemic use of VPA may bring harm to the stability of titanium implants in osteoporosis, SIM can reverse the negative effect of VPA on the osseointegration of titanium rods in ovariectomized rats.

Risks and complications associated with dental implant failure: Critical update

Risks and complications have been identified with dental implant failure though there is continuous innovation in implant systems and various interceptive treatment modalities. The success rate of dental implants has increased over a period of years as a treatment option for the rehabilitation of missing teeth. The dental implants are designed that best suits the various types of bone. Endosseous implants fail due to many reasons. Different reasons for the implant failure and their contributing factors have been discussed in this review article. A better understanding of the factors responsible for the implant failure will provide clinical decision-making and may enhance the field of implant dentistry. This article summarizes the factors causing implant failure. This paper presents the results of a survey of dentists practicing implant dentistry and updates regarding their knowledge of risk factors that they consider to be important for predicting dental implant failure.

Does HIV infection affect the survival of dental implants? A systematic review and meta-analysis

STATEMENT OF PROBLEM

Immunosuppression and coinfections associated with human immunodeficiency virus (HIV) infection pose a relative contraindication for dental implant therapy. However, although implants have been placed in patients with HIV with reasonable success, how HIV infection affects their survival is unclear.

PURPOSE

The purpose of this systematic review of the literature and meta-analysis was to analyze the data on the survival of dental implants in patients with HIV.

MATERIAL AND METHODS

A search for relevant articles published up to November 2019 was performed in PubMed/Medline and Cochrane databases, Clinicaltrials.gov, and Google Scholar. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were adopted for the conduct of the systematic review. The most pertinent data were extracted and pooled for qualitative and quantitative analyses with 95% confidence intervals. Heterogeneity was analyzed by using I-squared statistics.

RESULTS

A total of 8 studies involving 411 individuals with HIV and 1109 implants were included in the meta-analysis. The mean follow-up period was 2.8 years. A pooled estimate of 95% of implant survival rate with 95% confidence interval(92% to 96%) was noted. Heterogeneity across the 8 studies was found to be 41% with moderate true variability.

CONCLUSIONS

This systematic review demonstrated that HIV infection does not pose a serious threat to implant survival on short-term evaluation, but the evidence is of low quality.

Coating doxycycline on titanium-based implants: Two in vivo studies

Regardless of the substantial progress in designing titanium-based dental implants and aseptic techniques, infection remains as the most common complication after implantation surgeries. Although, having a weakened immune system or systematic diseases is not seen as contraindicated for dental implants anymore, controlling the immune system is required to avoid surgical site infections after implantation. These patients have to control the surgical site infections by taking a high daily dose of oral antibiotics after dental implantation. The antibiotics oral administration has many side effects such as gastrointestinal symptoms, skin rashes and thrush. Coating antibiotics on the biomaterials surface could be a promising solution to reduce these disadvantages through locally releasing antibiotics in a controlled manner. The aim of this study was to investigate the effects of doxycycline coating layer on titanium-zirconium alloy surfaces in vitro and in vivo. In our previous studies, we demonstrated the chemical presence of doxycycline layer in vitro. In this study, we examined its physical presence using field emission scanning electron microscope and confocal microscope. We also analyzed its controlled released manner using Nano-Drop UV Vis spectrometer. After in vitro characterization of the coating layer, we evaluated its effects on the implant osseointegration in dogs and rabbits. The histological and histomorphometrical results exhibited no significant difference between doxycycline coated and uncoated groups regarding the implants osseointegration and biocompatibility for dental applications. Therefore, coating a doxycycline layer on TiZr implants could be favorable for reducing or removing the antibiotics oral administration after the implantation surgery.

In vitro degradation of pure magnesium-the synergetic influences of glucose and albumin

The biocorrosion of magnesium in the external physiological environment is still difficult to accurately evaluate the degradation behavior in vivo, particularly, in the microenvironment of the patients with hyperglycemia or diabetes. Thus, we explored the synergistic effects of glucose and protein on the biodegradation of pure magnesium, so as to have a deeper understanding the mechanism of the degradation in vivo. The surface morphology and corrosion product composition of pure magnesium were investigated using SEM, EDS, FTIR, XRD and XPS. The effect of glucose and albumin on the degradation rate of pure magnesium was investigated via electrochemical and immersion tests. The adsorption of glucose and albumin on the sample surface was observed using fluorescence microscopy. The results showed that the presence of 2 g/L glucose changed the micromorphology of corrosion products on the magnesium surface by reacting with metal cations, thus inhibiting the corrosion of pure magnesium. Protein formed a barrier layer to protect the magnesium at early stage of immersion. The chelation reaction between protein and magnesium surface might accelerate the degradation at later stage. There may be a critical glucose (albumin) content. Biodegradation of pure magnesium was inhibited at low concentrations and promoted at high concentrations. The synergistic effect of glucose and protein restrained the adsorption of aggressive chloride ions to a certain extent, and thus inhibited the degradation of pure magnesium considerably. Moreover, XPS results indicated that glucose promoted the adsorption of protein on the sample surface.

Research on implants and osseointegration

Osseointegration was originally defined as a direct structural and functional connection between ordered living bone and the surface of a load-carrying implant. It is now said that an implant is regarded as osseointegrated when there is no progressive relative movement between the implant and the bone with which it is in direct contact. Although the term osseointegration was initially used with reference to titanium metallic implants, the concept is currently applied to all biomaterials that have the ability to osseointegrate. Biomaterials are closely related to the mechanism of osseointegration; these materials are designed to be implanted or incorporated into the living system with the aims to substitute for, or regenerate, tissues and tissue functions. Objective evaluation of the properties of the different biomaterials and of the factors that influence bone repair in general, and at the bone tissue-implant interface, is essential to the clinical success of an implant. The Biomaterials Laboratory of the Oral Pathology Department of the School of Dentistry at the University of Buenos Aires is devoted to the study and research of the properties and biological effects of biomaterials for dental implants and bone substitutes. This paper summarizes the research work resulting from over 25 years' experience in this field. It includes studies conducted at our laboratory on the local and systemic factors affecting the peri-implant bone healing process, using experimental models developed by our research team. The results of our research on corrosion, focusing on dental implants, as well as our experience in the evaluation of failed dental implants and bone biopsies obtained following maxillary sinus floor augmentation with bone substitutes, are also reported. Research on biomaterials and their interaction with the biological system is a continuing challenge in biomedicine, which aims to achieve optimal biocompatibility and thus contribute to patient health.

Intermittent parathyroid hormone 1-34 induces oxidation and deterioration of mineral and collagen quality in newly formed mandibular bone

Intermittent parathyroid hormone (PTH) administration is known to promote bone healing after surgical procedures. However, the mechanism and influence of PTH on the mineral and collagen quality of the jaw are not well understood. Most studies have focused on analyzing the bone density and microstructure of the mandible, and have insufficiently investigated its mineral and collagen quality. Oxidative stress activates osteoclasts, produces advanced glycation end products, and worsens mineral and collagen quality. We hypothesized that PTH induces oxidation and affects the mineral and collagen quality of newly formed mandibular bone. To test this, we examined the mineral and collagen quality of newly formed mandibular bone in rats administered PTH, and analyzed serum after intermittent PTH administration to examine the degree of oxidation. PTH administration reduced mineralization and worsened mineral and collagen quality in newly formed bone. In addition, total anti-oxidant capacity in serum was significantly decreased and the oxidative-INDEX was increased among PTH-treated compared to vehicle-treated rats, indicating serum oxidation. In conclusion, intermittent administration of PTH reduced mineral and collagen quality in newly formed mandibular bone. This effect may have been induced by oxidation.

Are There Contraindications for Placing Dental Implants?

There are few absolute contraindications to dental implant placement. Relative contraindications include cognitive decline, American Society of Anesthesiology patient status IV or higher categories, or medical conditions that may jeopardize the life or lifespan of the patient. Precautions for placing dental implants should be viewed with respect to the evidence-based exposures that can contribute to risk of failure, including but not limited to local, behavioral, and medical factors. Risk for dental implant failure increases in association with (1) past history of periodontal disease, (2) bruxism, (3) smoking, and (4) radiation therapy.

Influence of experimental alcoholism on the repair process of bone defects filled with beta-tricalcium phosphate

This study evaluated the effect of ethanol on the repair in calvaria treated with beta-tricalcium phosphate (β-TCP). Forty rats were distributed into 2 groups: Water group (CG, n = 20) and Alcohol Group (AG, n = 20), which received 25% ethanol ad libitum after an adaptation period of 3 weeks. After 90 days of liquid diet, the rats were submitted to a 5.0 mm bilateral craniotomy in the parietal bones; the left parietal was filled with β-TCP (CG-TCP and AG-TCP) and the contralateral only with blood clot (CG-Clot and AG-Clot). The animals were killed after 10, 20, 40 and 60 days. The groups CG-Clot and AG-Clot showed similar pattern of bone formation with a gradual and significant increase in the amount of bone in CG-Clot (22.17 ± 3.18 and 34.81 ± 5.49) in relation to AG-Clot (9.35 ± 5.98 and 21.65 ± 6.70) in periods of 20-40 days, respectively. However, in the other periods there was no statistically significant difference. Alcohol ingestion had a negative influence on bone formation, even with the use of β-TCP, exhibiting slow resorption and replacement by fibrous tissue, with 16% of bone formation within 60 days in AG-TCP, exhibiting immature bone tissue with predominance of disorganized collagen fibers. Defects in CG-TCP showed bone tissue with predominance of lamellar arrangement filling 39% of the original defect. It can be concluded that chronic ethanol consumption impairs the ability to repair bone defects, even with the use of a β-TCP biomaterial.

A pilot study using machine learning methods about factors influencing prognosis of dental implants

PURPOSE

This study tried to find the most significant factors predicting implant prognosis using machine learning methods.

MATERIALS AND METHODS

The data used in this study was based on a systematic search of chart files at Seoul National University Bundang Hospital for one year. In this period, oral and maxillofacial surgeons inserted 667 implants in 198 patients after consultation with a prosthodontist. The traditional statistical methods were inappropriate in this study, which analyzed the data of a small sample size to find a factor affecting the prognosis. The machine learning methods were used in this study, since these methods have analyzing power for a small sample size and are able to find a new factor that has been unknown to have an effect on the result. A decision tree model and a support vector machine were used for the analysis.

RESULTS

The results identified mesio-distal position of the inserted implant as the most significant factor determining its prognosis. Both of the machine learning methods, the decision tree model and support vector machine, yielded the similar results.

CONCLUSION

Dental clinicians should be careful in locating implants in the patient's mouths, especially mesio-distally, to minimize the negative complications against implant survival.

Patients' Socio-Economic Status, Tobacco and Medical History Associated with Implant Failure

Objective

To examine the potential association between patients’ characteristics that experienced implant failure and those who had successful implant treatment.

Materials and methods

This retrospective case-control study is based on 186 dental records of implant failure and 186 age and gender matched successful treatments for a total of 372 patients. Age at the time of the procedure, gender, medical history, tobacco use, dental insurance status, ZIP code and type of treatment provided (implant failure/successful implant treatment) were recorded.

Results

The population consisted of 47.6% females, 48.9% individuals with dental insurance and 9.7% self-reported tobacco users. A statistically significant association (p≤0.05) was found between implant failure and successful implant treatment in regards to tobacco use, socio-economic status and medical history. Insurance status and implant location (region, arch) did not affect significantly (p>0.05) the outcome of implant therapy.

Conclusions

Within the limitation of this retrospective case-control study, individuals with high socio-economic status, no history of tobacco use and history of heart attack were more likely to have a successful implant treatment than those with a low socio-economic status, tobacco users and without history of heart attack.

Factors Affecting the Occurrence of Complications in the Early Stages After Dental Implant Placement: A Retrospective Cohort Study

OBJECTIVE

To evaluate the background factors related to the occurrence of complications in the early stages after dental implant placement.

MATERIALS AND METHODS

A total of 289 outpatients who received dental implants were retrospectively evaluated for the presence or absence of complications. Background factors, including age, sex, implant width, implant length, implant site, number of implants placed, Periotest values at the time of implant placement, presence/absence of systemic disease (particularly diabetes), and the use of anticoagulation therapy, were compared between patients with and without complications. Logistic regression analysis was performed to identify significant risk factors for the occurrence of complications after dental implant placement.

RESULTS

Complications in the early stages after dental implant placement occurred in 25 (8.65%) patients. The patients with complications were older than those without complications (P = 0.003). In addition, the incidence of complications was significantly higher in patients with systemic diseases (P = 0.004) and in those receiving anticoagulation therapy (P = 0.005). Logistic regression analysis revealed that age was a significant risk factor (P = 0.025) for early-stage complications, whereas the number of implants, presence of diabetes, and the use of anticoagulation therapy were not significant risk factors.

CONCLUSIONS

Our results show that age is a significant factor influencing the occurrence of complications in the early stages after dental implant placement. Therefore, clinicians should consider this factor when developing their treatment strategies.

Effect of high-frequency loading and parathyroid hormone administration on peri-implant bone healing and osseointegration

The objective of this study is to examine the effect of low-magnitude, high-frequency (LMHF) loading, and anti-osteoporosis medications such as parathyroid hormone (PTH) and bisphosphonates on peri-implant bone healing in an osteoporosis model, and to assess their combined effects on these processes. Thirteen-week-old ovariectomized rats (n = 44) were divided into three groups: PTH, alendronate, and saline. After 3 weeks of drug administration, titanium implants were inserted into the tibiae. Each group was subdivided into two groups: with or without LMHF loading via whole-body vibration (50 Hz at 0.5 g, 15 min per day, 5 days per week). Rats were killed 4 weeks following implantation. Removal torque test, micro-CT analyses (relative gray (RG) value, water = 0, and implant = 100), and histomorphometric analyses (bone-to-implant contact (BIC) and peri-implant bone formation (bone volume/tissue volume (BV/TV))) were performed. Removal torque values and BIC were significantly differed by loading and drug administration (ANOVA). Post hoc analysis showed that PTH-treated groups were significantly higher than the other drug-treated groups. BV/TV was significantly enhanced by PTH administration. In cortical bone, RG values were significantly increased by loading. In trabecular bone, however, RG values were significantly increased by PTH administration. These findings suggest that LMHF loading and PTH can act locally and additively on the bone healing process, improving the condition of implant osseointegration.

Whole-body vibration and administration of a hormone used to treat osteoporosis can enhance bone healing at the site of a titanium implant. Toru Ogawa of Tohoku University Graduate School of Dentistry in Sendai, Japan, and colleagues gave anti-osteoporosis medications, either parathyroid hormone or the bisphosphonate drug alendronate, to female rat models of osteoporosis. After three weeks of drug administration or a saline control, the researchers inserted titanium implants into the rats’ leg bones. Half the rats were then exposed to whole-body vibration, which applies low-magnitude, high-frequency mechanical forces. A multitude of tests showed that parathyroid hormone improved bone healing at the implant more than alendronate or saline did. The vibrational stimulus further increased the healing. The findings suggest that these treatments could aid in oral bone healing for patients receiving dental implants.

Implant and root canal treatment: Survival rates and factors associated with treatment outcome

OBJECTIVES

To assess and compare the survival rates of implant and root canal treatment as well as to investigate the effect of patient and tooth related variables on the treatment outcome in a large-scale population-based study.

METHODS

Dental records of patients who received root canal treatment and implant therapy were retrieved from the electronic records of the University of Minnesota School of Dentistry. Demographic characteristics, dental insurance status, socioeconomic status as well as medical history and tobacco use were recorded. The treatment outcome was included as a binary variable (survival/failure).

RESULTS

A total of 13,434 records of patients who had implant (33.6%) or root canal therapy (66.4%) were included. The survival rate analysis and Kaplan-Meier table revealed the majority of the implants were removed within the first year (58.8%), while only 35.2% of the root canal treatments failed in the same time period. The overall survival rate was significantly (p < 0.001) higher for implant therapy (98.3%) compared to root canal treatment (72.7%). A statistically significant association was found between treatment (p <n0.001), age (p < 0.001) and anxiety (p = 0.004) with treatment outcome CONCLUSIONS: Implant therapy exhibited significantly lower failures when compared to root canal treatment, but the selection of either treatment should be based on multiple factors. Higher age and anxiety were also significantly associated with root canal and implant treatment failure.

CLINICAL SIGNIFICANCE

Clinicians are in an increased dilemma that affects the decision-making process due to the inadequate evidence in regards to the question of retention or extraction of a tooth in the natural dentition. This study demonstrated that both root canal and implant treatments are sound options with high survival rates; however, root canal therapy exhibited a significantly higher failure rate.

No clear evidence on the clinical performance of different removable prosthetic options in partially edentulous patients

Data sourcesMedline/PubMed, Embase, BIOSIS/Ovid, SciSearch/DIMDI, Cochrane library, FIZ Technik Web and hand searches of the journals; Clinical Oral Investigations, International Journal of Prosthodontics, Journal of Prosthetic Dentistry, Deutsche Zahnärztliche Zeitschrift, Swiss Dental Journal, Journal of Dentistry and the Journal of Dental Research.Study selectionRandomised controlled trials, prospective and retrospective studies on survival rates of removable dental prostheses in the moderately reduced dentition with at least 15 participants having an observation period of at least two years, and a dropout rate of less than 25% were considered.Data extraction and synthesisTwo reviewers abstracted data. A qualitative summary of the included studies was carried out. Studies providing data that permitted a Kaplan-Meier analysis were included in meta-analysis.ResultsThe review included 19 studies, six of which were in multiple publications. Cast-metal framework dentures showed failure rates of 33% and 50% after five years. One study with a 25-year observation period reported failure rates of 50%. Proper pretreatment and a good recall scheme improve the results. Bilateral attachment prostheses showed failure rates of 11% and 30% after five years. Unilateral attachment prostheses showed failure rates of 75% after five years. Double-crown prostheses dentures show failure rates of 0% to 21.7% after three to six years.ConclusionsWithin the limitations of this study, it seems that removable partial dentures, (RPD), given suitable pretreatment and follow-up regimes, can provide a satisfactory treatment option. Based on only one paper, they revealed acceptable results even over a very long observation period (25 years).

Dental implants and bone augmentation in HIV-infected patients under HAART: Case report and review of the literature

The present study reviewed the literature regarding dental implants in HIV-infected patients and reports the long-term follow-up of three clinical cases of patients under HAART that received bone augmentation and dental implants. The first case presents a young patient with a large defect in the mandible, as a consequence of a longitudinal fracture, that was treated with guided bone regeneration (GBR) previously to implant placement. The second case reported is middle-aged man with a fractured upper lateral incisor treated with immediate placement and simultaneous GBR to repair the dehiscence due to the buccal bone resorption. The third case shows an elderly patient that underwent sinus lifting with the simultaneous placement of two implants. All cases were treated after patients were medically controlled and followed for at least 10 years. Controlled HIV-infected patients undergoing HAART may be candidates to implant rehabilitation, as long as their plasmatic HIV viral load and CD4+ T lymphocytes count are within the parameters that indicate immune stability. Long-term stability of soft and hard tissues can be obtained maintaining function and esthetics. However, stronger evidence, based on prospective, controlled clinical trials is needed to provide the dental and medical teams with conclusive data.

Knowledge, attitudes, and perceptions of undergraduate dental students toward dental implants--an all India survey

PURPOSE

This study aims to gauge the knowledge and perceptions of undergraduate dental students or residents toward dental implants.

MATERIALS AND METHODS

The dental colleges in India were divided into 5 zones, and by random selection method, 7 colleges were selected from each zone. Thus, a total of 35 dental institutions were selected, which included 2800 residents. A printed questionnaire consisting of 15 questions, which assessed the level and source of information regarding implants, was prepared and distributed.

RESULTS

A total of 2800 questionnaires were posted of which 2041 responses were received (response rate was 72.89%). This study shows that 81.1% of the residents believed that they were not provided sufficient information and a whopping 91.7% of them coveted more information about implants in their undergraduate curriculum.

CONCLUSION

This study concludes that a revision in the undergraduate dental curriculum is required to make the students better equipped with the technicalities of implant dentistry.

Dental implants in patients affected by systemic diseases

Several systemic diseases (and relative medications) have been reported to impair or in some cases complicate dental implant surgery. In broader terms, when dealing with patients suffering from systemic diseases, the monitoring of the medical condition and of the related post-operative complications is of great importance in order to avoid risks which could jeopardise the health of the patient. In this review, the available evidence on implant survival/success, as well as relevant surgical recommendations in patients affected by systemic diseases, are evaluated and when possible, practical suggestions for the clinician are provided.

The role of lasers in the treatment of peri-implant diseases: A review

We reviewed the indexed literature regarding the efficacy of laser therapy in the treatment of peri-implantitis (PI). Databases were searched using combinations of the following keywords: peri-implantitis, bone loss, photodynamic therapy, laser, and light-activated disinfection. Titles and abstracts of publications from these search results were screened to determine which studies fulfilled the eligibility criteria. Full texts of relevant studies were read and independently assessed against the eligibility criteria. The resulting 28 studies described the role of lasers in the treatment of PI. The erbium:yttrium–aluminum-garnet laser can be used to sterilize implant surfaces without damaging them. Likewise, the carbon dioxide laser can disinfect implant surfaces and enhance the bone-to-implant contact around previously infected sites. Photodynamic therapy exhibits high target specificity and can destroy pathogens associated with the etiology of PI. Laser therapy can significantly reduce levels of clinical markers of peri-implant tissue inflammation (i.e., bleeding upon probing and clinical attachment loss) without jeopardizing the integrity of the implant or alveolar bone. In conclusion, laser therapy as an adjunct to conventional mechanical debridement therapy can be used effectively for the treatment of PI.

Risk Factors for Implant Failure and Peri-Implant Pathology in Systemic Compromised Patients

PURPOSE

To identify the possible risk factors for implant failure and peri-implant pathology in a population of systemically compromised patients.

MATERIALS AND METHODS

This retrospective clinical study included a total of 721 systemically compromised patients (422 women, 299 men), with an average age of 51 years (range: 20 to 87) rehabilitated with dental implants. The average follow-up time was 7.3 years. The patients' demographic variables (age and gender) and clinical variables (implant location, type of implant surface, and systemic conditions) were recorded. Outcome measures were implant failure and peri-implant pathology. Binary logistic regression models were performed to investigate the effect of the patients' demographic and clinical characteristics on the dependent variables implant failure and peri-implant pathology. A linear regression model was performed to correlate the patient's characteristics with the number of failed implants. Odds ratios (OR) with 95% confidence intervals and corresponding levels of significance were estimated for each variable.

RESULTS

Multivariate logistic regression disclosed increased age (patients over 40 years of age) as a risk factor for implant failure (OR = 2.63) and hepatitis as a risk factor for peri-implant pathology (OR = 3.74). Multivariate linear regression disclosed rheumatologic and cardiac diseases to be correlated with a higher number of failed implants.

CONCLUSIONS

Within the limitations of this study, the results suggest no absolute contraindications for implant rehabilitation in a population of systemically compromised patients. Nevertheless, this study suggests that increasing age, rheumatological condition, cardiovascular condition, and hepatitis should be considered when performing implant-supported rehabilitations due to their negative influence on the outcome.

Treatment of Orally Handicapped Edentulous Older Adults Using Dental Implants

The oral handicap of complete edentulism is the terminal outcome of a multifactorial process involving biological factors and patient-related factors. Fully edentulous orally handicapped older adults have been neglected because removable acrylic dentures have been the classic therapy for complete edentulism but are only rehabilitative, not therapeutic. Not replacing missing teeth with stable dentures could prevent adequate food intake. Osseointegrated endosseous implants used as a therapeutic adjunct can reduce the problem of long-term bone resorption to less than 0.1 mm per year. Implant-borne prostheses substantially increase the overall health and quality of life of orally handicapped fully edentulous older adults.

The effect of oxytocin on osseointegration of titanium implant in ovariectomized rats

INTRODUCTION

Oxytocin (OT) was reported to control differentiation of human mesenchymal stem cells and reverse osteoporosis (OP). This study investigated the effect of systematical treatment of OT on implant osseointegration in ovariectomized (OVX) rats.

MATERIAL AND METHODS

Twenty female rats received bilateral ovariectomy. Twelve weeks later, all animals were randomly assigned to control or experimental group. Each rat received two implants at the distal femoral metaphysis. From the first postoperative day, rats in experiment group received subcutaneous injection of OT (1 mg/kg · d), while animals in control group received vehicle. Twelve weeks after implantation, specimens containing implants were harvested and evaluated by histology, micro-CT, and push-out test. Tibiae were also harvested to evaluate the effect of OT on intact bone tissue of OVX rats.

RESULTS

Compared with control, OT treatment increased the relative bone volume surrounding the implant by 2.2 times, the percent implant osseointegration by 0.62 times, and the maximum push-out force by 2.25 times. Increased bone mass was also observed in histological sections of distal femur with implant and intact bone tissue of the proximal tibiae.

CONCLUSION

Systemic administration of OT promoted peri-implant bone healing and osseointegration of titanium implant and recovered the negative effects of OP in undisturbed bone tissue partially.

In vitro degradation of pure Mg in response to glucose

Magnesium and its alloys are promising biodegradable biomaterials but are still challenging to be used in person with high levels of blood glucose or diabetes. To date, the influence of glucose on magnesium degradation has not yet been elucidated, this issue requires more attention. Herein, we present pure Mg exhibiting different corrosion responses to saline and Hank’s solutions with different glucose contents, and the degradation mechanism of pure Mg in the saline solution with glucose in comparison with mannitol as a control. On one hand, the corrosion rate of pure Mg increases with the glucose concentration in saline solutions. Glucose rapidly transforms into gluconic acid, which attacks the oxides of the metal and decreases the pH of the solution; it also promotes the absorption of chloride ions on the Mg surface and consequently accelerates corrosion. On the other hand, better corrosion resistance is obtained with increasing glucose content in Hank’s solution due to the fact that glucose coordinates Ca²⁺ ions in Hank’s solution and thus improves the formation of Ca-P compounds on the pure Mg surface. This finding will open up new avenues for research on the biodegradation of bio-Mg materials in general, which could yield many new and interesting results.

Resilient Attachments as an Alternative to Conventional Cast Clasp Removable Partial Denture: 3-Year Follow-up

The present clinical report describes the prosthodontic management for a patient with uncontrolled bleeding and diabetes mellitus treated with a maxillary complete denture and a mandibular partial fixed dental prosthesis designed to interface with a removable cast framework partial denture retained by 2 ERA attachments. This approach was undertaken to improve both retention and stability of the distal extension Kennedy Class I removable partial denture. The rehabilitation provided better anterior esthetics than if treated with a conventional clasp retained removable partial denture, by employing a simple, practical design and offering a significant biomechanical advantages, restoring both oral health and function. Thus, this treatment modality, involving an ERA system and transfixation in fixed crowns, is an effective treatment and can be indicated as a clinical alternative for edentulous and partially edentulous patients with systemic disorders or for patients in economic situations that might preclude implant-based rehabilitation.

Implant Prosthetic Rehabilitation in Controlled HIV-Positive Patients: A Prospective Longitudinal Study with 1-Year Follow-Up

PURPOSE

The clinical trial aimed to evaluate the survival of implant-prosthetic rehabilitation in controlled HIV-positive patients.

MATERIALS AND METHODS

This mono-centric study included HIV patients with a stable disease, requiring implant rehabilitation, with good oral hygiene. Each patient received at least one dental implant. After 90 days in the upper jaw and 60 days in the lower jaw, the appropriate prosthesis was delivered.Primary outcome measures were prosthetic failures, implant failures, peri-implant marginal bone level changes (MBLCs), and biological complications (peri-implantitis, pus, pain, paresthesia). Data were recorded before the intervention (T0), and 6 (T1) and 12 months (T2) after.

RESULTS

Implants were positioned in 68 patients (22 females and 46 males; 194 implants). Two dropouts occurred for exacerbation of the disease before the sixth month of follow-up, and 66 patients (with 190 implants) completed the study. Forty-eight patients (70.6%) received total removable dentures; 11 patients (16.2%) received partial prosthesis, and nine patients (13.2%) received single elements.Implant failure occurred in nine patients (15 fixtures out of 190). These were early implant failures due to primary infection (five fixtures out of 190: 2.6%) and to peri-implantitis (10 fixtures out of 190: 5.2%). Prosthetic failure was registered in two patients (3% of patients) due to the loss of all the fixtures. Pus and pain were observed in 4/7 and 3/7 patients with peri-implantitis, respectively. No fractures of fixtures or paresthesia were registered. At T2, the mean peri-implant MBLC was -1.19 ± 0.87 mm.

CONCLUSIONS

Within its limitations, the study showed that in a well-controlled population of HIV patients implant rehabilitation can be a suitable options with results slightly worse to those obtained in normal population. A higher incidence of peri implant infections in the first six months was present pointing to the need of a proper protocol for infection control.

Indications and contraindications of dental implants in medically compromised patients: update

The aim of this study was to review the current scientific literature in order to analyse the indications and contraindications of dental implants in medically compromised patients. A reference research was carried out on PubMed using the key words “implant” AND (oral OR dental) AND (systemic disease OR medically compromised), in articles published between 1993 and 2013. The inclusion criteria were the following: clinical studies in which, at least, 10 patients were treated, consensus articles, reviewed articles and meta-analysis performed in humans treated with dental implants, and which included the disease diagnosis. A total of 64 articles were found, from which 16 met the inclusion criteria. Cardiac systemic diseases, diabetic endocrine pathologies or controlled metabolic disorders do not seem to be a total or partial contraindication to the placement of dental implants. Tobacco addiction, and head and neck radiotherapy are correlated to a higher loss of dental implants. Patients suffering from osteoporosis undergoing biphosphonates therapy show an increased risk of developing bone necrosis after an oral surgery, especially if the drugs are administered intravenously or they are associated to certain concomitant medication.

Key words:Dental implants, medically compromised patient, systemic diseases.

Effects of pH and elevated glucose levels on the electrochemical behavior of dental implants

Implant failure is more likely to occur in persons with medically compromising systemic conditions, such as diabetes related to high blood glucose levels and inflammatory diseases related to pH levels lower than those in healthy people. The aim of this study was to investigate the effects of lower pH level and simulated- hyperglycemia on implant corrosion as these effects are critical to biocompatibility and osseointegration. The electrochemical corrosion properties of titanium implants were studied in four different solutions: Ringer's physiological solution at pH = 7.0 and pH = 5.5 and Ringer's physiological solution containing 15 mM dextrose at pH = 7 and pH = 5.5. Corrosion behaviors of dental implants were determined by cyclic polarization test and electrochemical impedance spectroscopy. Surface alterations were studied using a scanning electron microscope. All test electrolytes led to apparent differences in corrosion behavior of the implants. The implants under conditions of test exhibited statistically significant increases in I(corr) from 0.2372 to 1.007 μAcm(-2), corrosion rates from 1.904 to 8.085 mpy, and a decrease in polarization resistances from 304 to 74 Ω. Implants in dextrose-containing solutions were more prone to corrosion than those in Ringer's solutions alone. Increasing the acidity also yielded greater corrosion rates for the dextrose-containing solutions and the solutions without dextrose.

Can the use of antibiotics interfere with the success of dental osseointegrated implants in diabetic patients?

AIM

The present review aims to discuss the last 10 years published data on the topic of the use of osseointegrated implants in diabetic subjects, particularly regarding the influence of antibiotics administration in the perioperative period.

BACKGROUND

In the last decades, oral rehabilitation significantly has evolved particularly with the use of osseointegrated implants. Increased life expectation of population is reflecting in a greater number of diabetic patients who might require dental osseointegrated implants rehabilitation. Diabetes was considered for a long time as a contraindication for oral implant placement. In this context, the use of antibiotics is still a controversial factor when we correlate it to implant success rate.

REVIEW RESULTS

Although 228 articles were initially selected for evaluation of proposed criteria, only 16 articles were considered valid. Among the 16 selected articles, only six articles represented clinical research that discussed the influence of the antibiotic in the success of osseointegration of dental implants in diabetic subjects. Five were retrospective studies and one a prospective research.

CONCLUSION

Data favors the use of antibiotics without significant side effects but clinical investigations of the need of prophylaxis antibiotic or therapeutic antibiotics are still scarce. The lack of adequate methodology is one of the main problems of the current articles. It is important to emphasize that studies should present detailed methodology in order to allow reproducibility.

CLINICAL SIGNIFICANCE

Permanent tooth loss is a pathological condition that affects millions of people worldwide. The possibility of successful treatment of edentulous areas through osseointegrated implants in those systemic compromised patients is a matter of scientific discussion. Although antimicrobial agents must be used rationally and carefully to avoid development of bacterial resistance, more studies are needed in order to support evidence regarding the influence of antibiotics in the success of dental implant surgery in diabetic patients.

The effect of nanometric surface texture on bone contact to titanium implants in rabbit tibia

Designing biomaterial surfaces to control the reaction of the surrounding tissue is still considered to be a primary issue, which needs to be addressed systematically. Although numerous in vitro studies have described different nano-metrically textured substrates capable to influence bone cellular response, in vivo studies validating this phenomenon have not been reported. In this study, nano-grooved silicon stamps were produced by laser interference lithography (LIL) and reactive ion etching (RIE) and were subsequently transferred onto the surface of 5 mm diameter Titanium (Ti) discs by nanoimprint lithography (NIL). Patterns with pitches of 1000 nm (500 nm ridge and groove, 150 nm depth), 300 nm (150 nm ridge and groove, 120 nm depth; as well as a 1:3 ratio of 75 nm ridge and 225 nm groove, 120 nm depth) and 150 nm (75 nm ridge and groove, 30 nm depth) were created. These samples were implanted in a rabbit tibia cortical bone. Histological evaluation and histomorphometric measurements were performed, comparing each sample to conventional grit-blasted/acid-etched (GAE) titanium controls. Results showed a significantly higher bone-to-implant contact at 4 weeks for the 300 nm (1:3) specimens, compared to GAE (p = 0.006). At 8 weeks, there was overall more bone contact compared to 4 weeks. However, no significant differences between the nano-textured samples and the GAE occurred. Further studies will need to address biomechanical testing and the use of trabecular bone models.