Fernando Suárez-López del Amo

Influence of Crown/Implant Ratio on Marginal Bone Loss: A Systematic Review

BACKGROUND With the increased use of short dental implants (<10 mm), a high crown/implant (C/I) ratio has become a common finding. However, the effect of the C/I ratio on the marginal bone loss (MBL) has not yet been examined extensively. Hence, the aim of the present systematic review is to explore the influence of the C/I ratio on the success rate and MBL of dental implants. METHODS Three electronic databases (PubMed, Ovid MEDLINE, and Cochrane Central) and a manual search for human trials with a minimal follow-up of 6 months are used for the present study. A statistical analysis of the influence of the C/I ratio was performed on the peri-implant MBL while considering follow-up period, type of implants, implant connection, and technical and biologic complications. RESULTS One hundred ninety-six potential articles were identified on the selected databases. Only 57 articles were selected for full-text evaluation. According to the inclusion criteria, a total of 13 articles were included in this systematic review. A significant negative association between the C/I ratio and the MBL was found (P = 0.012). However, no statistically significant difference was found (P >0.15) for potential effects regarding the observation period, the type of implant connection, or between both methods of evaluating the C/I ratio. CONCLUSIONS Within the limitations of the present study, the C/I ratio of implant-supported restorations has an effect on peri-implant marginal bone level. Within the range of 0.6/1 to 2.36/1, the higher the C/I ratio, the less the peri-implant MBL.

Influence of Soft Tissue Thickness on Peri-Implant Marginal Bone Loss: A Systematic Review and Meta-Analysis

BACKGROUND Multiple variables have been shown to affect early marginal bone loss (MBL). Among them, the location of the microgap with respect to the alveolar bone crest, occlusion, and use of a polished collar have traditionally been investigated as major contributory factors for this early remodeling. Recently, soft tissue thickness has also been investigated as a possible factor influencing this phenomenon. Hence, this study aims to further evaluate the influence of soft tissue thickness on early MBL around dental implants. METHODS Electronic and manual literature searches were performed by two independent reviewers in several databases, including Medline, EMBASE, and Cochrane Oral Health Group Trials Register, for articles up to May 2015 reporting soft tissue thickness at time of implant placement and MBL with ≥12-month follow-up. In addition, random effects meta-analyses of selected studies were applied to analyze the weighted mean difference (WMD) of MBL between groups of thick and thin peri-implant soft tissue. Metaregression was conducted to investigate any potential influences of confounding factors, i.e., platform switching design, cement-/screw-retained restoration, and flapped/flapless surgical techniques. RESULTS Eight articles were included in the systematic review, and five were included in the quantitative synthesis and meta-analyzed to examine the influence of tissue thickness on early MBL. Meta-analysis for the comparison of MBL among selected studies showed a WMD of -0.80 mm (95% confidence interval -1.18 to -0.42 mm) (P <0.0001), favoring the thick tissue group. Metaregression of the selected studies failed to demonstrate an association among MBL and confounding factors. CONCLUSION The current study demonstrates that implants placed with an initially thicker peri-implant soft tissue have less radiographic MBL in the short term.

Alveolar Bone Architecture: A Systematic Review and Meta-Analysis

BACKGROUND There is a need for studying bone characteristics systematically for a better understanding of planning (i.e., timing of placement and loading) and outcomes of implant therapy. Therefore, the aim of the present review is to evaluate alveolar bone microarchitecture and its modifiers. METHODS Two independent reviewers conducted electronic and manual literature searches in several databases, including MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Oral Health Group Trials Register, for articles published up to February 2015 reporting alveolar bone microstructure. The random-effect model was applied to calculate the weighted mean (WM) of total bone volume (TBV), which has a range from 0 to 1. TBV was stratified by anatomic locations, atrophic status, and types of specimens. Correlations between TBV and other bone-related parameters were also analyzed. RESULTS A total of 800 articles were initially identified. After abstract/full-text review, 24 articles were included in the systematic review, of which 23 were also included in the quantitative analysis. The WM TBV was 0.365 (95% confidence interval = 0.278 to 0.452), higher in the maxillary/mandibular anterior sites than the maxillary/mandibular posterior sites. However, great variations existed within each anatomic location. Additionally, WM TBV was lower in atrophic sites than non-atrophic sites. TBV was correlated negatively with trabecular spacing (R(2) = 0.11). CONCLUSIONS The present systematic review suggests that the TBV might not be different between the defined anatomic locations. However, the atrophy status might influence TBV.

Biologic Agents for Periodontal Regeneration and Implant Site Development

The advancement of molecular mediators or biologic agents has increased tremendously during the last decade in periodontology and dental implantology. Implant site development and reconstruction of the lost periodontium represent main fields in which these molecular mediators have been employed and investigated. Different growth factors trigger different reactions in the tissues of the periodontium at various cellular levels. Proliferation, migration, and differentiation constitute the main target areas of these molecular mediators. It was the purpose of this comprehensive review to describe the origin and rationale, evidence, and the most current understanding of the following biologic agents: Recombinant Human Platelet-Derived Growth Factor-BB (rhPDGF-BB), Enamel Matrix Derivate (EMD), Platelet-Rich Plasma (PRP) and Platelet-Rich Fibrin (PRF), Recombinant Human Fibroblast Growth Factor-2 (rhFGF-2), Bone Morphogenic Proteins (BMPs, BMP-2 and BMP-7), Teriparatide PTH, and Growth Differential Factor-5 (GDF-5).

Horizontal Bone Augmentation Using Autogenous Block Grafts and Particulate Xenograft in the Severe Atrophic Maxillary Anterior Ridges: A Cone-Beam Computerized Tomography Case Series

The aim of the present study was to use cone-beam computerized tomography (CBCT) to assess horizontal bone augmentation using block grafts, harvested from either the iliac crest (IC) or mandibular ramus (MR) combined with particulate xenograft and a collagen membrane for in the severe maxillary anterior ridge defects (cases Class III-IV according to Cadwood and Howells classification). Fourteen healthy partially edentulous patients requiring extensive horizontal bone reconstruction in the anterior maxilla were selected for the study. Nineteen onlay block grafts (from IC or MR) were placed. The amount of horizontal bone gain was recorded by CBCT at 3 levels (5, 7, and 11 mm from the residual ridge) and at the time of bone grafting as well as the time of implant placement (≈5 months). Both block donor sites provided enough ridge width for proper implant placement. Nonetheless, IC had significantly greater ridge width gain than MR (Student t test) (4.93 mm vs 3.23 mm). This was further confirmed by nonparametric Mann-Whitney test (P = .007). Moreover, mean pristine ridge and grafted ridge values showed a direct association (Spearman coefficient of correlation = .336). A combination of block graft, obtained from the IC or MR, combined with particulate xenograft then covered with an absorbable collagen membrane is a predictable technique for augmenting anterior maxillary horizontal ridge deficiency.

Non-Surgical Therapy for Peri-Implant Diseases: a Systematic Review

ABSTRACT Objectives The purpose of this paper was to systematically evaluate the effectiveness of non-surgical therapy for the treatment of peri-implant diseases including both, mucositis and peri-implantitis lesions. Material and Methods An electronic search in two different databases was performed including MEDLINE (PubMed) and EMBASE from 2011 to 2016. Human studies reporting non-surgical treatment of peri-implant mucositis and peri-implantitis with more than 10 implants and at least 6 months follow up published in English language were evaluated. A systematic review was performed to evaluate the effectiveness of the different methods of decontamination employed in the included investigations. Risk of bias assessment was elaborated for included investigations. Results Twenty-five articles were identified of which 14 were further evaluated and included in the analysis. Due to significant heterogeneity in between included studies, a meta-analysis could not be performed. Instead, a systematic descriptive review was performed. Included investigations reported the used of different methods for implant decontamination, including self-performed cleaning techniques, and professionally delivered treatment such as laser, photodynamic therapy, supra-/sub-mucosal mechanical debridement, and air-abrasive devices. Follow-up periods ranged from 6 to 60 months. Conclusions Non-surgical treatment for peri-implant mucositis seems to be effective while modest and not-predictable outcomes are expected for peri-implantitis lesions. Limitations include different peri-implant diseases definitions, treatment approaches, as well as different implant designs/surfaces and defect characteristics.

Comparison of Two Differently Processed Acellular Dermal Matrix Products for Root Coverage Procedures: A Prospective, Randomized Multicenter Study

BACKGROUND The purpose of this multicenter randomly controlled clinical trial was to compare two acellular dermal matrix (ADM) materials produced by different processing techniques, freeze-dried (FDADM) and solvent-dehydrated (SDADM) ADM, in their ability to correct Miller Class I and II recession defects. METHODS Eighty individuals from four study centers, each with a single maxillary anterior Miller Class I or II recession defect were enrolled. Participants were randomly assigned and treated with coronally advanced flap (CAF) + FDADM (n = 42) or CAF + SDADM (n = 38). Gingival thickness, recession depth, recession width, probing depth (PD), clinical attachment level, gingival index, plaque index, patient discomfort, and wound healing index were recorded before surgery (day 0), immediately after surgery (day 1), and 2, 4, 12, 24, and 52 weeks postoperatively. The Student t test, paired t test, and Kruskal-Wallis one-way ANOVA were used to analyze the data. RESULTS When evaluating the clinical parameters after 1 year, both groups showed significant (P <0.05) improvement for most of the parameters evaluated when compared to baseline (day 0). For example, percentage of root coverage was 77.21% ± 29.10% for CAF + FDADM and 71.01% ± 32.87% for CAF + SDADM. Conversely, no significant differences were observed between the two materials for any clinical parameter tested or for patient satisfaction except PD on the mesial side of the defects (P = 0.03). CONCLUSIONS Both FDADM and SDADM can be used successfully to correct Miller Class I or II recession defects. There were no statistically significant differences between groups for any of the clinical parameters tested.

Titanium activates the DNA damage response pathway in oral epithelial cells: A pilot study

PURPOSE To evaluate the effect of titanium (Ti) particles on oral epithelial cell homeostasis and the potential of dental implants to release Ti debris upon insertion. MATERIALS AND METHODS Dental implants with varying surface treatments were employed to determine the feasibility of particle release during implant placement as well as the impact of free Ti debris on oral epithelial cells. Ti particles derived from implant surfaces were isolated and cultured in direct contact with normal oral epithelial cells for 48 hours. Further, cells were fixed and processed for immunofluorescence assay to detect the activation of the DNA damage response (DDR) using CHK2 and BRCA1 molecular markers. Positive cells demonstrating DNA damage were quantified and statistically analyzed. RESULTS Ti particles derived from implants containing phosphate-enriched titanium oxide (PETO), fluoride-modified (FM), and grit-blasted (GB) surface treatments were able to activate CHK2 and trigger the recruitment of BRCA1 in oral epithelial cells. Also, implants with GB surfaces were able to release Ti particles upon implant placement. CONCLUSION The results indicate that Ti debris may be detached from the implant surface upon placement. Also, free Ti particles can trigger DDR signaling in oral epithelial cells. These findings suggest that Ti particles/debris released into a surgical wound may contribute to the disruption of epithelial homeostasis, and potentially compromise the oral epithelial barrier.

Reliability of Cone Beam Computed Tomography in Determining Mineralized Tissue in Augmented Sinuses

PURPOSE The aim of this study was to analyze cone beam computed tomography (CBCT) densitometries of maxillary sinuses augmented with human bone allograft. In addition, previously obtained microradiographic specimens were used to verify the diagnostic potential of CBCT. MATERIALS AND METHODS A two-stage protocol was conducted in 21 consecutive patients, all with a crestal bone height < 2 mm. Mineralized human bone allograft particles were used to augment sinuses using a lateral window approach. A succession of CBCT scans of the maxilla were taken before surgery, immediately after sinus augmentation, and 6, 10, and 18 months after implant placement. Using virtual probes, CBCT images taken at 6, 8, and 10 mm from the crestal surface were processed with medical imaging software and expressed as gray level (GL). RESULTS A total of 24 sinus augmentation procedures were performed in 21 patients. The average values of CBCT-GL ranged from 571 to 654, presenting the maximum value at 8 mm immediately after implant placement and the minimum value at 6 mm after 10 months. Furthermore, it was found that the graft mineral content decreased over time, completely disappearing between 10 and 11 months. CONCLUSION CBCT and the medical imaging software employed for imaging visualization are reliable tools to study biomaterial behavior after sinus augmentation procedures. In addition, results from this study demonstrate that a complete resorption of human bone allograft is possible. Due to the limited sample size, further clinical and morphometric studies are needed.

The Fate of Lateral Ridge Augmentation: A Systematic Review and Meta-Analysis

PURPOSE Owing to volumetric changes after tooth extraction, lateral ridge augmentation has become a common procedure prior or simultaneous to implant placement. Nonetheless, little is known with regard to the dimensional remodeling after healing of these lateral ridge augmentation procedures. Hence, the purpose of this systematic review was to assess the stability of bone grafting material between augmentation procedures and final healing, in terms of resorption rate. MATERIALS AND METHODS An electronic and hand literature search was conducted in several databases, such as the Cochrane Oral Health Group Trials Register, Embase, and Cochrane Central Register of Controlled Trials, up until February 2017. Only randomized controlled trials (RCTs) with a mean follow-up of at least 6 months after implant placement aiming to evaluate the stability of grafting material for lateral ridge augmentation were included and quantitatively analyzed. RESULTS A total of 35 articles were evaluated; however, only 17 RCTs met the inclusion criteria. A total of 15 studies reported information on bone resorption, leading to a total sample of 304 implants. The estimated overall mean horizontal bone gain at the time of regeneration was 3.71 ± 0.24 mm, with 4.18 ± 0.56 mm for the block graft technique and 3.61 ± 0.27 mm for guided bone regeneration (GBR). The estimated overall net bone gain at final re-evaluation (11.9 ± 7.8) was 2.86 ± 0.23 mm. The estimated mean (± SD) resorption after 6 months was 1.13 ± 0.25 mm, with 0.75 ± 0.59 mm for the block graft technique and 1.22 ± 0.28 mm for GBR. The implant survival rate was 97% to 100%. CONCLUSION Regardless of the material used for regeneration, different degrees of graft resorption should be expected. Given the sample of investigations analyzed in this review, block grafts seemed to maintain the volume of the initial augmentation site more than GBR techniques. During the initial stages of healing, the GBR technique experienced more changes compared with block grafts. The resorption of the xenograft group was inferior compared with the combination of xenograft and autologous bone groups. Consequently, overcorrection of the horizontal defects should be performed to compensate for the resorption of the grafting materials.