Carlos Garaicoa-Pazmino

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.

Epigenetic Modifications of Histones in Periodontal Disease.

Periodontitis is a chronic infectious disease driven by dysbiosis, an imbalance between commensal bacteria and the host organism. Periodontitis is a leading cause of tooth loss in adults and occurs in about 50% of the US population. In addition to the clinical challenges associated with treating periodontitis, the progression and chronic nature of this disease seriously affect human health. Emerging evidence suggests that periodontitis is associated with mechanisms beyond bacteria-induced protein and tissue degradation. Here, we hypothesize that bacteria are able to induce epigenetic modifications in oral epithelial cells mediated by histone modifications. In this study, we found that dysbiosis in vivo led to epigenetic modifications, including acetylation of histones and downregulation of DNA methyltransferase 1. In addition, in vitro exposure of oral epithelial cells to lipopolysaccharides resulted in histone modifications, activation of transcriptional coactivators, such as p300/CBP, and accumulation of nuclear factor–κB (NF-κB). Given that oral epithelial cells are the first line of defense for the periodontium against bacteria, we also evaluated whether activation of pathogen recognition receptors induced histone modifications. We found that activation of the Toll-like receptors 1, 2, and 4 and the nucleotide-binding oligomerization domain protein 1 induced histone acetylation in oral epithelial cells. Our findings corroborate the emerging concept that epigenetic modifications play a role in the development of periodontitis.

Incidence of implant buccal plate fenestration in the esthetic zone: a cone beam computed tomography study.

PURPOSE The aim of this cone beam computed tomography (CBCT) study was to investigate the incidence of fenestration and associated risk factors with virtual placement of an implant in the maxillary incisor region. MATERIALS AND METHODS Edentulous ridges missing a maxillary central or lateral incisor and amenable for single implant placement were included. Root-form implants (4×12 mm and 3.5×12 mm for the central and lateral incisors, respectively) were placed virtually in the edentulous space following the axis of the ipsilateral crown. Buccolingually, the implants were placed in the ideal prosthetic cingulum position. The angles of the ridge (RA) and implants (IA) in relation to the hard palate and the incidence of fenestration were recorded. RESULTS A total of 48 CBCT scans were analyzed. The mean RA and IA were 124.32 degrees and 110.91 degrees, respectively. Nine cases resulted in fenestration, equivalent to 18.75% of the total cases. The discrepancy between the RA and IA was statistically significantly larger in the fenestration sites (19.93 degrees) than in the nonfenestration sites (13.05 degrees). The concavity depth of the alveolar ridge was statistically significantly higher in the fenestration sites (4.79 mm) than in the nonfenestration sites (3.40 mm). CONCLUSION Within the limitations of this study, it can be concluded that the occurrence of fenestration is common (approximately 20%) if an implant is placed in the cingulum position with the axis following that of its restoration.

Personalized Medicine Approaches to the Prevention, Diagnosis, and Treatment of Chronic Periodontitis

Over the years, the multifactorial and interactive nature of periodontal disease challenged clinicians in an attempt to delineate a pattern for its destructive progression. Periodontal disease is caused by persistent inflammation of the periodontium in response to the colonization of microbes upon the tooth surface near the gingival margin and a subsequent biofilm formation resulting in irreversible attachment loss of marginal alveolar bone and associated periodontal ligament and migration of the junctional epithelium. In spite of the infectious nature of periodontal disease, identification of the oral microbiome and a complete understanding of its pathogenic pathway seem the most logical step toward the development of newer and effective approaches for periodontal therapy.

The sinus membrane-maxillary lateral wall complex: Histologic description and clinical implications for Maxillary sinus floor elevation

Maxillary sinus floor elevation has been documented as a safe and predictable procedure for gaining vertical bone height in the atrophic posterior maxillae. Conversely, there is a lack of basic research on the characteristics of the union between the sinus membrane (SM) and the bone. Clinical implications of an impaired union in healthy or pathologic membranes remain unknown. The objective of this study was to present a comprehensive histologic and morphologic description of the sinus membrane-lateral bone wall complex. In 14 fresh cadaver heads, 28 lateral wall sinus augmentation procedures were performed to obtain SM samples. Samples were assessed using hematoxylin-eosin, Masson trichrome, and toluidine blue staining and immunofluorescence and immunohistochemistry procedures. Specimens were coded and studied by a trained examiner using an optical microscope at ×4, ×10, ×40, and ×100 objectives. Thickness and inflammation status were assessed in these samples. Overall SM thickness of the samples was 0.40 ± 0.12 mm and was positively correlated to the inflammatory condition of the membranes. Such low values are the consequence of limited inflammation. Most of the fibers and cells in the deeper layers of the SM ran in a horizontal direction, oriented parallel to the underlying bone wall. In the immunohistochemistry study, 3 out of 7 samples showed a certain degree of nestin expression, suggesting osteogenic potential in spite of the elderly specimens. Large variations in thickness across the SM were found. These were noted to be partially correlated to the SM inflammatory status. The vast majority of the fibers were oriented parallel to the maxillary lateral wall, and only a few isolated areas showed a stronger perpendicular attachment. This might indicate the surpassing importance of the SM inflammatory status, operator skill, and other anatomical factors over the sinus membrane-maxillary lateral wall complex interface. Moreover, about half of the SM investigated were positive for nestin, indicating their osteogenic potential.

Effect of periodontal dressing on non-surgical periodontal treatment outcomes: a systematic review.

BACKGROUND Periodontal dressing has been advocated and showed some positive outcomes for placing over the surgical site after periodontal surgery. However, little is known about its effect on non-surgical therapy. PURPOSE The aim of this review was to assess the clinical effect of periodontal dressing when used after non-surgical therapy. MATERIAL AND METHODS Two examiners performed an electronic search in several databases for relevant articles published in English up to November 2013. Selected studies were randomized human clinical trials (prospective or retrospective trials) with the clear aim of investigating the effect of periodontal dressing placement upon periodontal non-surgical mechanical therapy. Data were extracted from the included articles for analysis. RESULTS Three randomized clinical trials fulfilled the inclusion criteria and thus were included in the data analysis. Statistical analysis could not be carried out due to the lack of clear data of the included studies. However, descriptive analysis showed its effectiveness in improving clinical parameters such as gain of clinical attachment level and reduction of probing pocket depth. CONCLUSION Placement of periodontal dressing right after non-surgical mechanical therapy can be beneficial in improving overall short-term clinical outcomes, although more controlled studies are still needed to validate this finding.

Implant success remains high despite grafting voids in the maxillary sinus

OBJECTIVES Given that the nature and presence of voids present within grafted sinuses following maxillary sinus elevation procedures were not known, nor was the contribution of these factors to implant success, the purpose of this study was to investigate these parameters and their relationship to implant success. MATERIALS AND METHODS This study evaluated data from 25 subjects who had a lateral window maxillary sinus augmentation procedure. Cone-beam computed tomography (CBCT) was performed at baseline and 4 months after surgery. CBCT images were used to evaluate grafted sites prior to implant placement. Using CBCT images, three examiners independently measured bone-grafted areas (BG), void areas (V), and percentage of void areas (V%) from six different sections within grafted sites. The six sections were defined as a cross-sectional (CS) midpoint, CS mesial point, CS distal point, horizontal section (HS) low point, HS midpoint, and HS high point. Implant success was also determined. RESULTS The calculated V% (V/BG) for the CS midpoint, CS mesial point, CS distal point, HS low point, HS midpoint, and HS high point were 5.30 ± 6.67%, 5.79 ± 8.51%, 6.67 ± 7.12%, 2.07 ± 2.56%, 5.30 ± 6.62%, and 4.92 ± 5.17% respectively. Implant success after 6 months of follow-up approximated 100%. CONCLUSIONS Although voids within grafts varied in terms of distribution and size, the V% within the HS low point were significantly smaller compared to those within the CS midpoint and CS distal point, which had the most intra-subject V%. Thus, more attention should be given to the distal aspect of the sinus when compacting graft materials in the lateral wall sinus augmentation procedure. Implant success was not influenced by the existence of voids as implant success remained high.

Assessment of Marginal Bone Loss around Platform-Matched and Platform-Switched Implants - A Prospective Study

The aim of the present study was to perform a software-assisted radiographic assessment of the effect of platform-switching on marginal bone loss (MBL) around dental implants. Forty patients requiring a dental implant in non-grafted partially edentulous mandibles were enrolled and categorized into implants receiving a platform-matched abutment (control group) or implants with a platform-switched abutment (test group). Standardized digital periapical radiographs were taken at the time of implant placement (T0), at implant loading (T1) and 1-year after functional loading (T2). Software-assisted radiographic assessment of the MBL horizontal, vertical and area changes was performed and compared between time intervals (T1-T0, T2-T1 and T2-T0). Mean radiographic horizontal MBL (hMBL) and vertical MBL (vMBL) from implant placement to 1-year after implant loading (T2-T0) were significantly increased around platform-matched when compared to platform-switched abutments (1.04 mm vs 0.84 mm, p<0.05) and (0.99 mm vs 0.82 mm, p<0.05), respectively. Additionally, bone loss area (BLa) was greater (0.77 mm2 vs 0.63 mm2; p<0.05) for platform-matched compared to platform-switched abutments. Platform-switching has a positive impact upon the amount of bone modeling after loading implants with internal hexagon connection.