Guided Customization and Fixation of Allogenic Cortical Lamina in Alveolar Bone Regeneration. A Case Report.

Bone reconstruction surgeries such as the autogenous and allogenic shell techniques where cortical laminates are used to regenerate bone defects, requires time and expertise to adapt and fix the laminated cortical blocks onto the defect area. This case report illustrates the process of customizing and fixing an allogenic cortical laminate (ACL) to reconstruct a horizontal bone defect with guided surgical stents. Two types of surgical stents were designed: one to aid in cutting a prefabricated ACL into the desired shape for the defect to be regenerated, and the other type of stent, was used to assist in the positioning and fixation of the resulting laminates. These stents enabled the clinician to regenerate a horizontal defect with reduced surgical time, increased precision and safety during laminate fixation. After 5 months of healing a dental implant could be placed in the regenerated site. The use of surgical stents in this type of bone regeneration surgeries can be helpful specially in more complex bone defects where precision is key. Further clinical studies are needed to validate this technique.

Narrow diameter titanium-zirconium tissue-level implants supporting multi-unit FDPs in the anterior area: A 5-year prospective study.

BACKGROUND: Narrow diameter implants (NDIs) are used in cases of limited mesio-distal space, or if the alveolar ridge does not allow placement of a standard diameter implant. PURPOSE: The aim of this prospective case series study is to present the 5-year clinical-, radiological-, and patient-reported outcome measures (PROMs) of patients with partial edentulism in the anterior area of the jaws requiring the placement of two narrow diameter implants to support a 3- or 4-unit fixed partial denture (FPD). MATERIALS AND METHODS: Thirty partially edentulous patients missing 3 or 4 adjacent teeth in the anterior area of the jaws were included in the study. Two titanium-zirconium tissue-level NDIs were placed in each patient in healed anterior sites (60 implants). A conventional loading protocol was performed to provide a FPD. Implant survival, success, marginal bone-level changes (MBL), clinical parameters, buccal bone stability with CBCT, adverse events and PROMs were recorded. RESULTS: The survival and success rates for the implants were 100%. The mean MBL (±SD) after prosthesis delivery, and 5-year follow-up (mean 58.8 months; range: 36-60) was 0.12 ± 0.22 and 0.52 ± 0.46 mm, respectively. Decementation and screw loosening were the most frequent prosthetic complications, yielding a prosthetic survival and success rates of 100% and 80%, respectively. Patient satisfaction was high with a mean (±SD) score of 89.6 ± 15.1. CONCLUSIONS: The use of tissue-level titanium-zirconium NDIs supporting splinted multi-unit FPDs in the anterior area seems to be a safe and predictable treatment option after a 5-year follow-up period.

Clinical Evidence on a Novel Macrohybrid Design Dental Implant with 12° Angled Platform: A Systematic Review.

Background: Immediate implant placement with immediate esthetics has become a more common procedure over time, though ensuring good emergence of the axis of the implant has been a challenge. A novel macroimplant design with an angled platform (Co-Axis®) has been developed to ensure exit of the head of the implant in the correct prosthetic position. A systematic literature review was carried to determine the survival rate and marginal bone loss associated with these implants. Material and Methods: An electronic and manual literature search was made in accordance with the PRISMA statement. The search strategy was limited to human studies, retrospective and prospective clinical trials, cross-sectional studies, and cohort studies reporting outcomes of a novel macrohybrid implant with a 12° angled implant connection. Results: Three articles met the inclusion criteria and were reviewed in the analysis. The estimated success rate was 95.9%. The global marginal bone loss was estimated to be -0.17 ± 0.58 mm in an environment characterized by great heterogeneity (I2 = 99%). The estimated mean implant stability was 69.6 ± 0.92 (ISQ). As only two studies provided the required information, it was not possible to determine publication bias. Lastly, mean recession was estimated to be practically zero (0.06 ± 0.23 mm), with great heterogeneity. Conclusions: Within the limitations of this systematic review, it can be affirmed that immediate implant treatment with Co-Axis® implants shows a survival rate of 95.9% at one year of follow-up, with low marginal bone loss values, near-zero soft tissue recession, and favorable papilla index values. Nevertheless, the great heterogeneity of the data requires the findings to be interpreted with caution.

The Screen Technique for Safe Bone Regeneration of Noncontained Defects: A Novel Technique.

Healing complications in guided bone regeneration (GBR) can be frequent when nonresorbable membranes are used. Exposure of dense polytetrafluoroethylene (d-PTFE) membranes to the oral cavity are usually located close to the incision line due to a lack of tension-free flap closure. This case report presents a safe, novel technique that uses d-PTFE membranes placed on the missing buccal and palatal bone walls without covering the coronal aspect of the regeneration. Therefore, these membranes can be kept away from the incision line to minimize the risk of exposure. The coronal part is then covered with a resorbable membrane. A clinical case is presented, using this novel technique to three-dimensionally reconstruct noncontained defects in the maxilla. This technique is safe and effective in regenerating these defects; after 8 months of healing, three implants could be placed with proper primary stability. Further, histologic and histomorphometric analyses revealed functional bone with areas of new bone formation. However, more long-term studies are required to validate this technique.

Evaluation of Peri-implant Tissue Stability and Patient Satisfaction After Immediate Implant Placement in the Esthetic Area: A 3-Year Follow-up of an Ongoing Prospective Study.

Horizontal and vertical reduction of the ridge has to be expected after tooth extraction. Immediate implant placement and provisionalization is a viable treatment option that can help to minimize those changes. Additionally, it can better meet a patient's expectations about the treatment, reducing time and invasiveness. The aim of this prospective study is to evaluate the stability of the hard and soft tissues surrounding single immediate implants placed in the esthetic zone, as well as evaluating patient satisfaction. A total of 16 implants were placed, and 15 could be evaluated at the 3-year follow-up. Radiographic and clinical data was recorded after this period. Some marginal bone level reduction was detected after 3 years but was not statistically significant. The soft tissues, measured at 3 points, showed stability and even better positions with respect to the day of the final restoration placement. Patient satisfaction was analyzed using the modified Oral Health Impact Profile questionnaire (OHIP-14), and high satisfaction values were reported. The implementation of a precise surgical and prosthetic protocol when an immediate implant is placed into a fresh extraction socket is likely to result in high survival and success rates combined with excellent patient satisfaction. After the 3-year follow-up, favorable results were present.

Blood absorption capacity of different xenograft bone substitutes. An in-vitro study.

BACKGROUND: Commercially available xenograft blocks, claim to have adequate characteristics to interact with biological media and thus permitting biological fluid absorption. The objective of this in vitro study was to compare the blood absorption capacity of four different xenograft block materials of different composition of collagen and porosity. MATERIAL AND METHODS: Four brands of xenograft block materials were used (NuOss®, Bio-Oss®, Osteobiol® and Smartbone®). Five samples of each brand were analyzed, making a total of 20 tests. Human blood was used as the absorption liquid for the present experiment. The time period, in which the block remains in contact with the blood, was registered at 30 seconds (T1), 60 seconds (T2) and 5 minutes (T3). The xenograft blocks were evaluated according to their absorption capacity. RESULTS: The absorption capacity of the different biomaterials were statistical significant different (p<0,001) at T1, T2 and T3 time points. At 30 seconds, Smartbone® absorbed significantly less blood than NuOss® and Bio-Oss®, however, without differences comparing with Osteobiol®. The NuOss®, Bio-Oss® and Osteobiol® did not register any significant difference between them. At 60 seconds, the Smartbone® absorbed significantly less blood than the other biomaterials. CONCLUSIONS: The NuOss® was significantly superior than Osteobiol®, but without differences relatively with Bio-Oss®. Also the Bio-Oss® and Osteobiol® did not register any difference between them. At 5 minutes, the Smatbone® continued to significantly absorbed less blood than any other biomaterial, nevertheless, NuOss®, Bio-Oss® and Osteobiol® not register again any significant difference between them. Despite of small sample size, it can be concluded that NuOss® was superior, in terms of blood absorption capacity, comparing with the other block biomaterials at 30 seconds, 60 seconds and 5 minutes. However, more investigation in a clinical setting are needed to know the clinical implications of the absorption capacity of such biomaterials. Key words:Blood absorption, osteoconduction, xenograft, bone regeneration.

Comparison of Three Biphasic Calcium Phosphate Block Substitutes: A Histologic and Histomorphometric Analysis in the Dog Mandible.

The purpose of this animal study was to determine which ratio of hydroxyapatite (HA) and tricalcium phosphate (TCP) is the most appropriate in the composition of alloplastic biphasic block grafts, in terms of bone density and bone formation, for the regeneration of alveolar defects. Different concentrations of HA/TCP were used for the alloplastic block grafts: 100/0 (HA100 group), 79/21 (HA75 group), and 57/43 (HA50 group); the control treatment filled the defect with a collagen plug. All control and test sites were covered with a resorbable collagen membrane. Sacrifices were performed at 4, 12, and 24 weeks after grafting. Microcomputed tomography and histologic and histomorphometric analyses were performed to determine bone density and the characteristics of the regenerated bone as well as the percentages of newly formed bone (NB), residual material (RM), and connective tissue (CT). Bone density increased significantly over time (P < .001), with stabilization between 12 and 24 weeks (P = 1.000). No differences in density were observed between the different test blocks (P = .813). The percentage of NB increases over time, independent of the concentration (P < .001). At 12 weeks, the control group exhibited more NB than the HA100 group (P < .001). At 24 weeks, the HA50 group exhibited more NB than the HA100 (P < .001) and control (P = .066) groups. At 24 weeks, the HA100 and HA75 groups showed high RM percentages. The HA50 group exhibited an increased tendency of less RM percentage compared with the HA100 and HA75 groups. Although slight differences were found, the HA50 group's HA/TCP ratio seems the appropriate concentration when taking into account the bone density and percentage of NB and RM at 12 and 24 weeks of healing.

Influence of Implant Position in Implant-Assisted Removable Partial Denture: A Three-Dimensional Finite Element Analysis.

PURPOSE: To determine the ideal position of a dental implant to assist a posterior extended partial removable dental prosthesis (PRDP), through stress values, displacement values, and deformation of periodontal ligament (PDL). MATERIALS AND METHODS: A finite element analysis of different implant positions was analyzed using a 3D mandible model from a human patient. Test models were created: model A (implant in second molar area), model B (implant in the first molar area), and model C (implant in premolar area). A control model without implant support was also created. Overall displacement values, von Mises stress distribution maps, and nonlinear deformations were evaluated. RESULTS: Some differences could be observed between test models. The introduction of an implant in the edentulous area, unlike a conventional removable partial denture without implant support, decreases stress values in the biological structures such as: mandible, tooth, soft tissue, and PDL. Placing the implant in the first molar area resulted in improved displacement values, and reduced maximum stress values at the peri-implant bone area, metal structure, and implant were observed. CONCLUSIONS: Within the limitations of this study we can conclude that placing the implant in the position of the first molar improves biomechanical behavior of implant-assisted PRDPs.

On the search of the ideal barrier membrane for guided bone regeneration.

BACKGROUND: GBRs are essential procedures in implant dentistry and periodontology where barrier membranes play an important role by isolating soft tissue and allowing bone to grow. Not all membranes function the same way, as they differ from their origin and structure, it is important to understand how membranes behave and differ one from others in order to achieve a predictable treatment. MATERIAL AND METHODS: A systematic search on Medline by two independent reviewers was performed for articles published until July 2017 reporting the characteristics or properties of barrier membranes. The question that preceded the search was designed according to PICO rules. RESULTS: A total of 124 articles were initially identified from electronic searching. After abstract/full-text review, 21 were included for a systematic review. According to the extracted data and article analysis, barrier membranes should fulfill the following criteria in order to success: biocompatibility, space maintaining, occlusive function, easy - handling and a bioactivation friendly property. With the development of new biomaterials and surfaces, a great advance in this area is expected. CONCLUSIONS: It has been clearly described that biocompatibility is the most important requirement to take into account when choosing a membrane, but other factors such as space maintaining capacity, cell oclusiveness, easy handling and bioactivation friendly materials are the ones that will fulfill our necessities. Key words:Barrier membrane, guided bone regeneration, dental implantology, oral surgery, collagen membrane, biomaterial.

Short-term retrospective case series of implant-assisted removable partial dentures with locator abutments.

The purpose of this retrospective case series was to report on the clinical performance of implant-assisted removable partial dentures (IARPDs) with Locator abutments in different partial edentulism situations, with a mean follow-up period of 28.6 months. Twelve consecutive patients were treated with IARPDs. A total of 24 implants were placed in the edentulous area. Minimum follow-up period was 12 months. Overall patient satisfaction, health of peri-implant tissues, survival of implants and abutments, and prosthetic complications were reported. Overall implant survival was 91.6%; two implants failed. No major complications were reported-only one IARPD metal framework broke. No Locator abutment loosening was reported. Within the limitations of this retrospective study, treatment with IARPDs can improve the patient's function, phonetics, and esthetics without the need for extensive bone regeneration surgeries and prosthodontic rehabilitations. However, well-designed prospective clinical studies on IARPDs are needed to support their long-term use.