Quantitative analysis of fibrillar collagen organization in the immediate proximity of embedded fibroblasts in 3D collagen hydrogels.

Fibroblasts embedded in a 3D matrix microenvironment can remodel the matrix to regulate cell adhesion and function. Collagen hydrogels are a useful in vitro system to study cell-matrix interactions in a 3D microenvironment. While major matrix reorganizations are easily recognizable, subtle changes in response to environmental or biochemical cues are challenging to discern in 3D hydrogels. Three-dimensional collagen gels at 1.0 mg/ml vs 1.5 mg/ml were labelled with DQ-collagen and imaged by confocal reflectance microscopy to evaluate these small changes. An image analysis pipeline was developed, hydrogel area and number of crosssections analysed were optimized, and fibrillar collagen properties (number of branches, number of junctions, and average branch length) were quantified. While no significant changes were seen in fibrillar collagen organization between 1.0 mg/ml and 1.5 mg/ml collagen hydrogels, embedded mouse fibroblasts caused a significant increase in collagen branching and organization. Using the phalloidin-labelled cells, this change was quantitated in immediate proximity of the cell. A distinct increase in branch and junction numbers was observed, significantly altered by small changes in collagen concentration (1.0 mg/ml vs 1.5 mg/ml). Together, this analysis gives a quantitative evaluation of how cells respond to and modify their immediate microenvironment in a 3D collagen hydrogel.

Contour Augmentation for Periodontal Defects (CAPD) for Periodontally Compromised Teeth with Horizontal Bone Loss: A Prospective Cohort Assessment at 1 Year.

This study assessed the effects of buccal contour augmentation for periodontally compromised teeth with horizontal bone loss. A total of 30 subjects were divided into Group A or Group B (n = 15 subjects per group). Group A received open-flap debridement (OFD) with buccal contour augmentation using deproteinized bovine bone mineral (DBBM), jointly referred to as contour augmentation for periodontal defects (CAPD; test group). Group B received only OFD (control group). Bleeding on probing (BOP), clinical attachment level (CAL), probing depth (PD), gingival recession (GR), keratinized mucosa width (WKM), keratinized mucosa thickness (TKM), and labial cortical plate thickness were compared at baseline and 1 year. BOP, CAL, PD, and GR did not show significant differences. TKM increased by 1.76 mm for Group A but decreased by 1 mm for Group B. WKM increased from 2.86 ± 0.4 mm to 3.6 ± 0.71 mm (P < .001) and from 2.93 ± 0.32 mm to 3 ± 0.7 mm (P = 0.5) for Groups A and B, respectively, which showed statistical significance. Labial cortical plate thickness increased from 0.94 ± 0.3 mm to 1.95 ± 0.54 mm (P < .001) for Group A but decreased from 0.87 ± 0.45 mm to 0.68 ± 0.31 mm for Group B. Visual analog scale scores for pain perception showed no difference between the two groups. CAPD for periodontally compromised teeth improves WKM and TKM. Long-term analyses are needed to determine its benefits in daily clinical practice.

Cone Beam Computed Tomography Analysis of Posterior-Superior Alveolar Canal from a Fixed Reference Point: Implications for Sinus Floor Elevation Procedure through Lateral Approach.

Objective: Sinus floor elevation is commonly done in the maxillary posterior region prior to dental implant placement. This study primarily aimed at assessing the location of the posterior superior alveolar artery (PSAA) canal on cone beam computed tomography (CBCT) scans and its relation to the alveolar ridge and maxillary sinus from a fixed reference point. Material and Methods: A total of 226 edentulous maxillary molar sites were included in this retrospective analysis. The distance from the PSAA to the sinus floor (SF), alveolar crest (AC) and a fixed reference point, that is, the roof of sinus (RS) were measured. The alveolar bone height (ABH), thickness of the crestal keratinized mucosa (CKM) and thickness of Schneiderian membrane (SM) were also evaluated. Results: 54 sites (23.89%) were excluded from the study. The SF, AC, RS and ABH values averaged at 11.91 mm ± 3.63 mm, 16.05 mm ± 3.96 mm, 25.32 mm ± 7.13 mm and 4.93 mm ± 4.27 mm respectively. SF and AC was higher in second molar than first molar region (p < 0.001), but RS did not show significant difference (p = 0.85). CKM and SM averaged at 2.02 mm ± 0.68 mm and 1.31 mm ± 0.81 mm respectively. Conclusion: The PSAA can be visualized in CBCT scans with a prevalence of 76.11% and may not be detected when adherent to the sinus membrane. This study stresses on the need for a CBCT, prior to sinus surgeries through lateral approach, to assess the PSAA.

Clinical Comparison of Vascular Bleeding Time Creep Between Osseodensification and Conventional Drilling of Implant Osteotomy Sites.

This study compared the onset of vascular bleeding between osseodensification and conventional drilling of implant osteotomy sites. Patients with type III trabecular bone requiring a single missing tooth replacement were included and allocated to either Group A (test) or Group B (control). In Group A, the osseodensification group (OD), an implant osteotomy was carried out using Densah Burs (Versah) in the counterclockwise direction; in Group B, the standard drilling group (SD), Densah Burs were run in the clockwise direction. An endoscope was introduced into the osteotomy to visualize and measure the time taken for initiation of bleeding (BI) and for blood to fill the osteotomy site (BF). A total of 40 osteotomy sites (23 in the maxilla and 17 in the mandible) were included in this cross-sectional study. The mean age of study participants was 50.1 ± 8.28 years. The mean BI time for Groups A and B was 18.54 ± 2.48 seconds and 16.89 ± 1.92 seconds, respectively (P = .02); the mean BF time for Groups A and B was 41.92 ± 3.19 seconds and 37.95 ± 2.73 seconds, respectively (P < .001). Osseodensification does not seem to negatively affect or induce loss of bone vascularity. Clinicians should note that osseodensified sites might take slightly longer to fill with blood following an osteotomy.

A double lateral pedicle graft technique for palatal recession coverage on dental implants.

Rough surfaces of dental implants, when exposed to the oral environment, are conducive to biofilm colonization and can predispose the affected implant to periimplantitis. Recession coverage using soft-tissue grafts is one of the treatment modalities used for the treatment of exposed implant threads. Recession coverage on the palatal aspect of maxillary implants is difficult due to the firm nature of the palatal mucosa and, consequently has not been widely documented in the literature. This case report documents a novel double-pedicle technique for palatal recession coverage on a dental implant. Two pedicle grafts were obtained from either side of the implant with the mucosal recession: a full-thickness lateral-pedicle graft from the distal aspect and a subepithelial connective tissue pedicle from the mesial aspect. The connective tissue pedicle was stabilized first on the area of mucosal recession and was then covered with the distal full-thickness lateral pedicle. Complete recession coverage was obtained, and the result was observed to be clinically stable after 18 months of follow-up. The technique demonstrated in this report can be a useful tool for the treatment of localized palatal recessions on dental implants.

Buccal Contour Grafting for Periodontally Compromised Teeth with Horizontal Bone Loss: Prospective Cohort Assessment at 1 Year.

The effects of buccal contour augmentation, for periodontally compromised teeth with horizontal bone loss, was assessed in this study. 30 subjects were divided into group A (open flap debridement [OFD] with buccal contour augmentation using deproteinized bovine bone mineral [DBBM]), jointly referred to as Contour augmentation for Periodontal Defects (CAPD); and group B (OFD alone). Bleeding on probing (BOP), clinical attachment level (CAL), probing depth (PD), gingival recession (GR), width (WKM) and thickness (TKM) of keratinized mucosa and labial cortical plate thickness were compared at baseline and 1-year. BOP, CAL, PD and GR did not show significant differences. TKM increased by 1.76 mm for group A, while decreased by 1 mm for group B. WKM increased from 2.86 ± 0.4 mm to 3.6 ± 0.71 mm (p<0.001) and 2.93 ± 0.32 mm to 3 ± 0.7 mm (p = 0.5) for groups A and B respectively, which showed a statistical significance. Labial cortical plate thickness increased from 0.94 ± 0.3 mm to 1.95 ± 0.54 mm (p<0.001) for group A, while decreased from 0.87 ± 0.45 mm to 0.68 ± 0.31 mm for group B. Visual analog scale score for pain perception showed no difference between the 2 groups. Contour augmentation (CAPD) with DBBM for periodontally compromised teeth improves WKM and TKM. Long-term analyses are needed to determine its benefits in daily clinical practice.

Comparative Assessment of Bovine Versus Porcine Xenograft for Augmentation: A Randomized Prospective Cohort Study.

This study compared the bone turnover and volume stability of bovine-derived xenografts (Cerabone) vs porcine-derived xenografts (MinerOss XP) in horizontal ridge augmentation (HRA) for veneer contour and extraction socket preservation (ESP), with a 6-month follow-up. Participants were divided into Group 1 (HRA + bovine), Group 2 (HRA + porcine), Group 3 (ESP + bovine), and Group 4 (ESP + porcine). Buccolingual ridge width was measured on CBCT scans at baseline and 6 months. Representative histologic core samples were taken from the ESP groups at 6 months. Each group comprised 10 subjects (40 subjects total). The buccolingual width for Groups 1 and 2 increased from 5.43 ± 1.82 mm and 5.75 ± 1.64 mm (P = .36) to 7.75 ± 1.91 mm and 8.75 ± 1.38 mm (P = .03), respectively. However, the buccolingual widths for Groups 3 and 4 decreased from 6.3 ± 1.26 mm and 6.74 ± 1.29 mm (P = .16) to 5.8 ± 1.21 mm and 6.61 ± 1.56 mm (P = .01), respectively. Significantly lower dimensional changes were noted in Group 4 at 6 months. Porcine xenografts serve as a stable biocompatible osteoconductive bone substitute and expand a clinician's choice of bone grafts in dental applications.

A Clinical Guide for Treatment of Dental Cervical Lesions Through a Restorative, Surgical, or Combination Approach: A Proposed Evidence-Based Algorithm.

The incidence of dental cervical carious and noncarious lesions is common, and often these are treated with a restorative material without due attention paid to the amount of exposed cementum/enamel, level of interproximal bone, and final desired esthetic result. This article is intended to provide clinicians an evidence-based clinical decision tree for treating such lesions through a restorative, surgical, or combination approach such that the optimum functional and cosmetic result is achieved.

Long-term evaluation (7 years) of coronally advanced flap with (CAF) and without (e-CAF) vertical release incisions using a subepithelial connective tissue graft in the treatment of multiple recession-type defects.

OBJECTIVES: The objective of this retrospective study was to compare the 7-year outcomes of coronally advanced flap with vertical incisions (CAF) and the envelope type of flap (e-CAF), using a subepithelial connective tissue graft (SCTG) in the treatment of multiple recession defects. METHOD AND MATERIALS: Twenty-two patients (13 CAF and 9 e-CAF) with at least two adjacent recession defects in the esthetic zone contributed to a total of 50 sites (29 CAF and 21 e-CAF). Complete root coverage (CRC), mean root coverage (MRC), and keratinized tissue (KT) width were recorded over the course of the study. RESULTS: In the short term (8 months), CRC, MRC, and KT outcomes were similar between the groups (P > .05). However, at the 3-year follow-up, the e-CAF group displayed significantly higher KT, MRC (100%), and CRC (100% at both tooth- and patient-levels) than the CAF group (MRC 91.43%; CRC 79.31% at tooth-level and 69.23% at patient-level). Similarly, at the 7-year follow-up, statistically significantly superior KT, MRC (94.24%), and CRC (87.71% at tooth-level and 77.78% at patient-level) values were recorded for the e-CAF group compared to the CAF group (MRC 68.98%; CRC 31.03% at tooth-level and 15.38% at patient-level). CONCLUSIONS: Despite similar treatment outcomes recorded by both surgical procedures in the short term, sites treated with e-CAF showed better stability of the gingival margin and superior KT width in the medium (3 years) and long term (7 years).

The Graft Infusion Technique (GIT) for Treatment of Peri-Implantitis Defects: Case Series.

Peri-implantitis is a site-specific infectious disease that causes an inflammatory process in soft tissues, and bone loss around an osseointegrated implant in function. Several techniques with non-surgical or surgical debridement and decontamination followed by ongoing supportive therapy or regeneration of the peri-implant bone defects have been proposed in the literature. However, the literature is still unclear on an effective protocol for implant surface decontamination or the appropriate choice of regenerative materials. This case series describes a surgical technique to treat peri-implantitis osseous defects using a mixture of deproteinized bovine bone mineral with 10% porcine collagen (DBBM-C) in a block form, soaked in an appropriate antibiotic. The use of this combination provides advantages such as good graft adaptability along with localized antibiotic release without the use of systemic antibiotics. Thus, this technique might be an effective method to treat amenable peri-implantitis defects. Additionally, the proposed algorithm also allows for customized culture based antibiotic loading. To the best of the authors' knowledge, this is the first case series documenting this technique for peri-implantitis defects. Long-term studies with controlled samples would be necessary for further evaluation.

Evaluating Mouse Fibroblast Interaction with Implant Surfaces in a 3D Microenvironment.

PURPOSE: Previous studies assessing fibroblast interactions with implants have mainly relied on measurements such as cell migration, gene expression, and cell adhesion. For these studies, testing cellular behavior at the implant surface was done by imaging the cell-implant interface using standard microscopy techniques in 2D tissue culture dishes. The true behavior of cells relative to the implant can best be assessed in a more physiologic 3D microenvironment. MATERIALS AND METHODS: The embedding of the implant disks in 3D collagen gels was standardized with labeled fibroblasts to allow the imaging of fibroblast morphology and behavior when proximal to or binding to the implant disks. This allowed comparison of the behavior of laser-microgrooved and machined implant disk surfaces quantitatively in an in vitro 3D microenvironment. RESULTS: This in vitro imaging assay revealed for the first time in a 3D microenvironment setting the statistically significant impact laser-microgrooved disk surfaces have on both cell adherence and recruitment of cells in proximity to the disk. It also allowed visualization of membrane protrusivity and cytoskeletal organization in cells adherent to the implant disk. CONCLUSION: This assay provides a simple and effective way of observing cell behavior on and around the implant disk surface in a more physiologic 3D setting. Within the limits of this study, it revealed that the laser-microgrooved implant surface demonstrates significant superiority in fibroblast recruitment and binding in a 3D microenvironment.

Inappropriate Socket Shield Protocol as a Probable Cause of Peri-Implant Bone Resorption: A Case Report.

Alveolar ridge remodeling post-extraction is a well-documented process. Alveolar bone is in a continuous state of remodeling even after implant placement, and this leads to changes in the contour of the peri-implant tissues over the years. A vast number of procedures have been described in literature to address and correct this resorption including procedures like socket grafting, dual zone grafting, socket shield (partial extraction therapy) and many more. Socket shield (partial extraction therapy) is a relatively new procedure described in the literature. This technique aims to try and slow down this remodeling and maintain the peri-implant tissues in a state near normalcy. The aim of this article is to assess a case where the possible cause of buccal bone loss around an integrated implant was an inappropriately prepared socket shield. It is recommended that an evidence-based consensus be put forth on both case selection and execution to minimize inappropriate execution of this technique by the average clinician.

Cystic epithelial lining seen around a dental implant: A case report of a rare finding.

Dental implants have been successfully used for over 30 years, with a low complication rate. Peri-implant pathologies have recently seen an increase in incidence. This case report elucidates a rare case implant failure that occurred shortly after prosthetic loading, where the clinical signs mimicked peri-implant disease and attending bone loss, but the final histological report confirmed presence of a cystic lining around the implant. The manuscript also emphasizes the possible causes and management of such complications. To the best of our knowledge, this represents one of the first publication of an evident peri-implant cystic lining in a case exhibiting no radiographic evidence of the same.

Three-Dimensional Alveolar Bone Assessment of Mandibular First Molars with Implications for Immediate Implant Placement.

The aim of this retrospective study was to evaluate the alveolar dimensions of the mandibular molar using cone beam computed tomography (CBCT) for immediate implant placement. The width of buccal (WB) and lingual (WL) bone; width of interradicular bone 2 and 4 mm apical to the furcation and at the apex (IRB2, IRB4, and IRBA, respectively); and distance to the inferior alveolar nerve from the furcation (IAN-F) and mesial (IAN-M) and distal (IAN-D) roots were evaluated from CBCT records of 126 subjects (200 mandibular first molars). Mean WB (0.84 ± 0.39 mm) and WL (2.71 ± 1.17 mm) measurements showed significant differences (P = .003). Differences between IAN-F, IAN-M, and IAN-D measurements averaged at 14.14 ± 2.57 mm, 4.31 ± 1.06 mm, and 4.61 ± 1.02 mm, respectively. IRB2, IRB4, and IRBA dimensions were 1.93 ± 0.65 mm, 2.54 ± 0.9 mm, and 4.46 ± 1.91 mm, respectively. The findings of the study demonstrate the alveolar bone morphology of the mandibular first molar and the need for CBCT scans for proper treatment planning for immediate implant placement.

In Vitro Surface Testing Methods for Dental Implants-Interpretation and Clinical Relevance: A Review.

More than 2,000 dental implant options are estimated to be available for any given clinical situation. Because many implants have claims that are substantiated mainly on the basis of in vitro studies, it is prudent for clinicians to understand the interpretation of such studies and possible clinical relevance. In vitro tests can be segregated as surface analysis tests and mechanical assessment tests. With a wide variation of methodologies used and results achieved by different implant manufacturers, practitioners may find it difficult to judge the clinical significance of in vitro tests. This article provides an overview, including limitations, of the in vitro implant analysis tests implant companies routinely perform, ranging from older methods involving mechanical testing and surface microscopy to more recent tests such as atomic force microscopy (AFM) studies and gene expression tests, to assist clinicians when choosing an implant system. Having identified the limitations of in vitro testing methods, the current evidence indicates that scanning electron microscopy may be useful in providing insight on the role of implant surface topography. AFM, single cell tests, 3D imaging, and gene expression tests could be useful for assessment of cellular and physio-biochemical properties. 3D finite element analysis may help in the evaluation of mechanical properties of dental implants. Clinicians are encouraged to correlate the findings of in vitro tests with robust animal histologic studies and well-designed, high-quality clinical research to ascertain optimum clinical results.

Quantitative Assessment of the Edentulous Posterior Maxilla for Implant Therapy: A Retrospective Cone Beam Computed Tomographic Study.

AIM: Dimensional changes of the alveolar bone are often noted in horizontal and vertical planes as a sequel to tooth extraction, particularly in the maxillary posterior region due to alveolar bone resorption combined with pneumatization of the sinus. The aim of this retrospective study was to quantitatively assess the maxillary residual alveolar ridge using cone beam computed tomography (CBCT) scans. MATERIALS AND METHODS: A total of 349 edentulous sites from 250 CBCTs were evaluated. The apico-coronal bone height and bucco-palatal crest width were measured in sagittal and coronal slices, respectively. Additionally, the obliqueness of the sinus floor at the edentulous sites was also evaluated. RESULTS: One hundred and twelve (55.45%) of the molar and 74 (54.42%) of the premolar sites had a horizontal ridge dimension < 6 mm, whereas 137 (67.83%) of the molar and 61 (44.86%) of the premolar sites showed an apico-coronal height < 8 mm. Furthermore, 183 (54.14%) of the evaluated sites had an oblique sinus floor morphology. CONCLUSION: Additional augmentative procedures are thus required in a high percentage of the population at the edentulous maxillary posterior site for rehabilitation using a standard dimension implant. This study stresses on the need for a three-dimensional CBCT prior to implant surgery for proper treatment planning.

Osseodensification -- A systematic review and qualitative analysis of published literature.

The recently introduced technique of osseodensification for dental implant involves the use of special drills (Densah) run in a counter-clockwise direction at the osteotomy site. It is claimed that this causes expansion of the osteotomy site, and increases density of the bone in immediate vicinity of the osteotomy. We reviewed published papers on the primary stability attained using this drilling technique. As a secondary finding, the bone to implant contact (BIC) and the bone area fraction occupancy (BAF) was also compared between the conventional drilling protocol and the osseodensification protocol, among these articles. A Systematic search was performed in PubMed-Medline, Embase and Google Scholar for clinical/animal studies up to November 2018. A total of 12 articles, from a database of 132 articles, consisting of 8 animal histologic studies, 2 human based clinical studies, 1 case series and 1 case report were assessed. 10/12 articles measured the insertion torque values, 7/12 articles measured the BIC and 6/12 articles estimated the BAF between the two techniques. Quality assessment of 8 studies performed using ARRIVE guidelines showed that 6/8 studies had a high score. An average increase in the insertion torque, BIC and BAF was noted in the osseodensification group as compared to the conventional drilling group. Since most of these studies are non-clinical, it can be inferred that osseodensification is an efficient way to enhance primary stability of implants in low density bone in an animal model. However, extrapolation to long term clinical success cannot be ascertained until further evidence becomes available.

Long-Term Outcomes of Coronally Advanced Tunnel Flap (CATF) and the Envelope Flap (mCAF) Plus Subepithelial Connective Tissue Graft (SCTG) in the Treatment of Multiple Recession-Type Defects: A 6-Year Retrospective Analysis.

This study evaluated the 6-year results of the subepithelial connective tissue graft (SCTG) plus envelope-type flap (modified coronally advanced flap; mCAF) or coronally advanced tunnel flap (CATF) in the treatment of multiple recessions. Thirty-six patients with at least two adjacent recessions were included. Complete root coverage (CRC), mean root coverage (MRC), and keratinized tissue (KT) width were recorded over the course of the study. Both groups presented similar CRC, MRC, and KT outcomes between the 1-year and 6-year follow-ups. MRC decreased from 96.90% to 94.16% for mCAF, and from 89.56% to 83.10% for CATF. Both surgical techniques were similarly efficient in treating multiple recessions in the short term, and in maintaining the stability of therapy in the medium and long term.

Determination of the center of anteroposterior curve of occlusion in a selected local population: A cross-sectional cephalometric study.

OBJECTIVE: The objective of this paper was to cephalometrically determine the center of the anteroposterior curve of occlusion, and its relation to standardized landmarks, to establish a suitable occlusal curve for the restoration of maxillary and mandibular arches in a selected local population. To the best of the authors' knowledge, this was the first cephalometric study identifying variations occurring in the anteroposterior curve in this population. MATERIALS AND METHODS: A total of 80 patients (40 males and 40 females) with Angle's Class I occlusion and normal growth pattern were selected. Landmarks were established following tracings on standardized lateral cephalograms. The center of the occlusal curve was determined, and its distance from the nasion, lachryma, and orbitale was statistically compared using ANOVA, post hoc and proximal matrix tests in males and females. In addition, a relationship between the depth of occlusal curve and the condyle was established. RESULTS: The mean distances of the center from nasion, lachryma, and orbitale (statistically significant) were 11.15 mm ± 5.65 mm, 18.68 mm ± 8.6 mm and 33.10 mm ± 10.13 mm for females (P < 0.001) and 9.7 mm ± 4.69 mm, 16.80 mm ± 6.45 mm and 31.22 mm ± 8.51 mm (P < 0.001) for males, respectively. Depth of the curve and distance from the condyle had an inverse corelation. CONCLUSION: Nasion is closest to the center of the curve of occlusion in both females and males followed by lachryma and orbitale. Hence, nasion can be considered as a point of reference clinically while determining anteroposterior curve of occlusion.

Controlled Palatal Harvest Technique for Harvesting a Palatal Subepithelial Connective Tissue Graft.

Subepithelial connective tissue grafts (SCTGs) have been extensively used to augment soft-tissue volume on dental implants and natural teeth. The authors present a technique called the controlled palatal harvest (CPH) to obtain SCTGs. CPH provides an alternative to the trap-door and single-incision techniques currently utilized. The objective of this article is to describe this harvesting technique for SCTGs. A case report is presented in which the CPH technique was successfully used to obtain a SCTG. Contrary to current techniques where the SCTG is usually taken from the palatal (bone) side, this technique involves the dissection of a thick split-thickness flap in which the graft is harvested from the raised flap. Further, an L-shaped incision (with an anterior release) improves visibility and dexterity during dissection of the connective tissue graft. This technique enables the operator to maintain a certain minimum overlying flap thickness, and excellent control is ensured over the thickness of the harvested SCTG. The thickness of theremaining connective tissue overlying the palatal can also be controlled by the operator. Thus, the chances of leaving behind a thin tissue covering the palatal bone are reduced, minimizing necrosis and flap sloughing, which further improves grafting success. While the CPH can be used as an alternative to currently employed conventional harvest techniques, it may require greater operator skill. To the best of the authors' knowledge, this is the first report that documents such a technique.