Purpose: The purpose of the study was to analyze and compare the stress distribution in the so-called All-on-Four concept where two anterior implants were placed parallel to each other and two posterior implants were tilted at 45° angle against the four parallelly placed implants within the interforaminal distance in an edentulous mandible. Materials and Methods: The three-dimensional finite element analysis models consisted of cancellous bone surrounded by the cortical bone, four dental implants positioned in two different designs – i.e., four parallelly placed implants (Model 1) and All-on-Four concept (Model 2) with hybrid superstructures comprising of a Hader bar. The vertical (60N, 130N, and 300N) and lateral (20N, 45N, and 100N) loading protocols were considered and von Mises stress values were determined. Results: On vertical and lateral loading, lower stress concentrations were observed in the peri-implant region in Model 2. However, there was higher stress concentration noticed on cortical, cancellous bone and bar attachment due to the tilting of implants in every condition. Conclusion: Within the limitations of the study, All-on-Four concept is an optimal and viable treatment option if executed accurately as it reduces the cantilever length, reduces stress concentrations in the peri-implant region, and is cost-effective.

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Prosthodontic implant rehabilitation remains one of the most complex restorative challenges because of the most usual troubles with regard to the lack of adequate treatment planning. Position, angulation, implant diameter, and length of an implant need to be determined before the surgical procedure is planned. This article briefs about the novel technique of presurgical mock up of implant site and evaluation of implants – Position, angulation, and complexity of procedure on the study model.

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Background: Tapered implants imitate the natural form of the root. They are known to enhance primary stability by providing pressure on the cortical bone of regions with poor bone qualities and also has a good survival rate as it directs stresses away from the crestal cortical bone while transferring it to the cancellous bone. Purpose: Maxillary anatomic constraints sometimes make it necessary to surgically position implants at angles that are not optimal for prosthetic restorations or by positioning the implant in the area with the greatest available bone, with the intention of correcting the implant alignment at the time of prosthetic restoration. This is made possible, in carefully planned cases with the use of angulated abutments. Materials and Methods: Three tapered implants with triangular, square, and buttress thread designs having a 15° and 25° angulated abutment were created. The implant models were positioned in anterior maxillary bone D2 and D3 and clinical loading conditions simulated. The maximum equivalent von Mises stress values were recorded and analyzed using ANSYS software. Results: The finite element analysis carried out showed less stresses from tapered implant square thread design in D2 and D3 bone with 15° angulated abutment, while buttress thread design performed better in D2 and D3 bone with 25° abutment angulation on axial and nonaxial loading. Conclusion: Bone type is an important factor that affects stress distribution. More stress occurred in D3 bone compared to D2 bone type. Thus, bone type should be carefully considered when choosing the most appropriate implant design.

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Context: Several materials have been used for maxillary sinus augmentation for subsequent implant-supported prosthetic rehabilitation. No perfect material has been identified for the purpose. Aims: The aim of the study is to clinically and radiographically evaluate the use of Sterile Demineralized bone matrix (Osseograft™) for maxillary sinus augmentation and subsequent implant-supported prosthetic rehabilitation. Subject and Methods: Sinus augmentation and implant placement were carried out in twenty patients with Osseograft™. Using intraoral periapical radiographs, radiographic implant length (rIL), residual bone height at the mesial (mRBH) and residual bone height at the distal (dRBH) aspects of the implant, and height of the graft apically (aGH) were measured. Residual bone height (RBH) = Mean of mRBH and dRBH, implant penetration (IP) =difference between rIL and RBH, Extent of the sinus lift (SL) = sum of IP and aGH were calculated and a qualitative assessment of maturation was performed using the Sinus Grafting Remodeling Index (SGRI). Statistical Analysis Used: Descriptive statistics. Results: The mean residual bone height immediately after surgery was 6.81 mm. The mean IP length was 5.45 mm. The mean aGH was 3.21 mm. The mean extent of the SL was 8.89 mm. At 3 months and 6 months, the mean aGH was 2.68 mm and 2.57 mm. The mean SL at 3 months and 6 months was 7.84 mm and 7.73 mm. The SGRI was 1 in all cases immediately postsurgery; between 1 and 2 at the end of 3 months; 2 in 15 cases and 1 in 4 cases at the end of 6 months. Conclusion: Osseograft™ can be used as an effective material for sinus augmentation with minimal complications and morbidity to the patient.

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Purpose: Maxillary sinus pneumatization is usually noted after posterior teeth extraction. The pneumatization occurs at the expense of the alveolar bone and may compromise the residual ridge dimensions for further procedures. This article aimed to assess three dimensionally the linear and volumetric changes of the maxillary sinus following posterior teeth extraction using a split mouth study design. Materials and Methods: Fifty cone-beam computed tomography (CBCT) scans with unilateral missing molar(s) or premolar(s) were assessed. Linear craniocaudal measurement from the orbital floor to the maxillary alveolar ridge was noted, and the sinus volume was measured using 3Diagnosys software (v3.1, 3Diemme, Cantu, Italy) and compared between the test and control side. Statistical analysis was performed using a paired Student's t-test. Results: Linear dimensions of the maxillary sinus increased from 33.12 (±3.99) mm on the control side to 33.34 (±3.95) mm on the test side (P = 0.0005). An increase in the volume from 13.78 (±2.55) ml to 13.99 (±2.61) ml was observed in the control and test side, respectively (P = 0.0002). Conclusion: A significant increase in sinus dimension and volume is seen after posterior teeth extraction. This may hinder further implant-supported rehabilitative procedures in this region.

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Statement of Problem: The importance of implant collar/neck in crestal bone area triggered the need to understand the influence of its design/surface topography on surrounding hard and soft tissues. Purpose: This study analyzed the effect of machined and rough surface of implant collar on bone level at crestal region and surrounding soft tissues in maxillary and mandibular anterior region. Materials and Methods: The clinical study was conducted on 20 participants (15 males and 5 females) based on the inclusion and exclusion parameters. Participants were broadly divided into two groups with 10 dental implants in Group R (implant with rough collar design) and Group M (implant with machined collar design). The participants were evaluated at baseline (within 1 week after implant placement), 3 months, and 6 months for crestal bone level and soft tissue parameters (pink esthetic score [PES]). Results: All implants showed clinically acceptable bone loss at interval of 6 months, i.e., 0.68 and 0.74 on mesial and distal aspect of R group implants, respectively, and 1.15 and 0.83 at mesial and distal aspect of R group implants, respectively. And also, the PES of all implants observed was above the clinical acceptability level, i.e., 6.15 and 6.05 for R and M groups implants, respectively. Conclusion: It can be concluded from the present study that there is no significant difference statistically in bone level at crestal region and soft tissues parameters in two different implant collar designs used in the study although the loss of bone observed was higher in machined group in comparison to rough group of implants and the PES observed was also more in R group in comparison to M group.

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Partial rehabilitation in the posterior edentulous region remains a challenge due to the anatomical condition present in the area. Excessive pneumatization of the maxillary sinus and accentuated bone crest resorption following teeth extraction cause bone atrophy and may lead to impossibility of inserting standard implants. Constant efforts are aiming at the reduction of the invasiveness of implant surgery. This has led to increase the use of implants with shorter length in the posterior maxilla and mandible region which reduces the need for additional surgical procedure causing less morbidity of the site and faster healing of the region. Does crown to implant ratio has an effect on the marginal bone loss (MBL) around implants in the posterior maxillary and mandibular region? A systematic search was conducted on two databases for the studies published from January 1, 2006, to July 31, 2018. Cross-references were checked. Hand searching was done in the library. Studies were included if they were done among healthy, nonhospitalized individual, and compared for the crown-to-implant ratio and MBL. A total of 143 articles were found through search. Thirteen articles remained after removing duplicates, reading the full text and reviewing abstracts. Thirteen articles were included for the data extraction. Crown-to-implant ratio has no role in the crestal bone loss, but other factors need to be evaluated for its role along with crown-to-implant ratio that can cause the MBL.

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Several therapies for tissue regeneration in implantology have been explored for their ability to enhance bone regeneration such as low-level laser therapy (LLLT), also known as photobiomodulation. This technique has been shown to reduce inflammation and edema, induce analgesia, and promote healing in a range of musculoskeletal pathologies with cost-effective for healing therapy. The endothelial progenitor and hematopoietic stem cells, together with LLLT improving their capacity to induce angiogenesis, recruit other cells to a site of injury and secrete growth factors and cytokines that have a paracrine effect on surrounding cells. A critical review and comprehensively analyze of tissue regeneration associated to newer regenerative techniques as LLLT, platelet derivatives and mesenchymal stem cells (MSCs) at preimplant sites was released. An electronic search in PubMed via Medline and Embase was conducted of publications from the previous 10 years. English language articles related to the subject were found using selected keywords. We summarize the photobiomodulation properties and its relation with platelet derivatives and MSCs and discuss the efficacy of these therapies for tissue repair. The LLLT is well-documented therapy but further research studies relating LLLT to tissue regeneration in periodontics and implantology are needed.

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