Tae Ju Oh

Angiogenic Biomarkers and Healing of Living Cellular Constructs

The use of intra-oral soft-tissue-engineered devices has demonstrated potential for oral mucosa regeneration. The aim of this study was to investigate the temporal expression of angiogenic biomarkers during wound healing of soft tissue reconstructive procedures comparing living cellular constructs (LCC) with autogenous free gingival grafts. Forty-four human participants bilaterally lacking sufficient zones of attached keratinized gingiva were randomly assigned to soft tissue surgery plus either LCC or autograft. Wound fluid samples were collected at baseline and weeks 1, 2, 3, and 4 post-operatively and analyzed for a panel of angiogenic biomarkers: angiogenin (ANG), angiostatin (ANT), PDGF-BB, VEGF, FGF-2, IL-8, TIMP-1, TIMP-2, GM-CSF, and IP-10. Results demonstrated a significant increase in expression of ANT, PDGF-BB, VEGF, FGF-2, and IL-8 for the LCC group over the autograft group at the early stages of wound repair. Although angiogenic biomarkers were modestly elevated for the LCC group, no clinical correlation with wound healing was found. This human investigation demonstrates that, during early wound-healing events, expression of angiogenic-related biomarkers is up-regulated in sites treated with LCC compared with autogenous free gingival grafts, which may provide a safe and effective alternative for regenerating intra-oral soft tissues (ClinicalTrials.gov number, NCT01134081).

Management of the implant periapical lesion: a case report.

The implant periapical lesion (IPL), a possible cause for implant failure, may occur from the presence of pre-existing microbial pathology such as endodontic/periodontal lesions. This case report presents a case history related to IPL, which was caused by a pre-existing endodontic lesion. In addition, other possible causes such as surgical trauma and the management strategies of IPL are suggested. For the treatment of the infected form of IPL, a sequential surgical therapy can be utilized. This includes surgical removal of the implant or implant apical region, thorough debridement of the infected lesion, systemic antibiotics, and/or guided bone regeneration. The implant therapy should be directed to minimize the occurrence or consequences of IPL by careful diagnosis, systematic treatment planning, and appropriate treatment procedures.

Hard and Soft Tissue Changes After Crestal and Subcrestal Immediate Implant Placement

BACKGROUND The purpose of this study is to assess the influence of the placement level of implants with a laser-microtextured collar design on the outcomes of crestal bone and soft tissue levels. In addition, we assessed the vertical and horizontal defect fill and identified factors that influenced clinical outcomes of immediate implant placement. METHODS Twenty-four patients, each with a hopeless tooth (anterior or premolar region), were recruited to receive dental implants. Patients were randomly assigned to have the implant placed at the palatal crest or 1 mm subcrestally. Clinical parameters including the keratinized gingival (KG) width, KG thickness, horizontal defect depth (HDD), facial and interproximal marginal bone levels (MBLs), facial threads exposed, tissue-implant horizontal distance, gingival index (GI), and plaque index (PI) were assessed at baseline and 4 months after surgery. In addition, soft tissue profile measurements including the papilla index, papilla height (PH), and gingival level (GL) were assessed after crown placement at 6 and 12 months post-surgery. RESULTS The overall 4-month implant success rate was 95.8% (one implant failed). A total of 20 of 24 patients completed the study. At baseline, there were no significant differences between crestal and subcrestal groups in all clinical parameters except for the facial MBL (P = 0.035). At 4 months, the subcrestal group had significantly more tissue thickness gain (keratinized tissue) than the crestal group compared to baseline. Other clinical parameters (papilla index, PH, GL, PI, and GI) showed no significant differences between groups at any time. A facial plate thickness ≤1.5 mm and HDD ≥2 mm were strongly correlated with the facial marginal bone loss. A facial plate thickness ≤2 mm and HDD ≥3 were strongly correlated with horizontal dimensional changes. CONCLUSIONS The use of immediate implants was a predictable surgical approach (96% survival rate), and the level of placement did not influence horizontal and vertical bone and soft tissue changes. This study suggests that a thick facial plate, small gaps, and premolar sites were more favorable for successful implant clinical outcomes in immediate implant placement.

The Effect of Flapless Surgery on Implant Survival and Marginal Bone Level: A Systematic Review and Meta-Analysis

BACKGROUND The clinical outcomes of implants placed using the flapless approach have not yet been systematically investigated. Hence, the present systematic review and meta-analysis aims to study the effect of the flapless technique on implant survival rates (SRs) and marginal bone levels (MBLs) compared with the conventional flap approach. METHODS An electronic search of five databases (from 1990 to March 2013), including PubMed, Ovid (MEDLINE), EMBASE, Web of Science, and Cochrane Central, and a hand search of peer-reviewed journals for relevant articles were performed. Human clinical trials with data on comparison of SR and changes in MBL between the flapless and conventional flap procedures, with at least five implants in each study group and a follow-up period of at least 6 months, were included. RESULTS Twelve studies, including seven randomized controlled trials (RCTs), one cohort study, one pilot study, and three retrospective case-controlled trials (CCTs), were included. The SR of each study was recorded, weighted mean difference (WMD) and confidence interval (CI) were calculated, and meta-analyses were performed for changes in MBL. The average SR is 97.0% (range, 90% to 100%) for the flapless procedure and 98.6% (range, 91.67% to 100%) for the flap procedure. Meta-analysis for the comparison of SR among selected studies presented a similar outcome (risk ratio = 0.99, 95% CI = 0.97 to 1.01, P = 0.30) for both interventions. Mean differences of MBL were retrieved from five RCTs and two retrospective CCTs and subsequently pooled into meta-analyses; however, none of the comparisons showed statistical significance. For RCTs, the WMD was 0.07, with a 95% CI of -0.05 to 0.20 (P = 0.26). For retrospective CCTs, the WMD was 0.23, with a 95% CI of -0.58 to 1.05 (P = 0.58). For the combined analysis, the WMD was 0.03, with a 95% CI of -0.11 to 0.18 (P = 0.67). The comparison of SR presented a low to moderate heterogeneity, but MBL presented a considerable heterogeneity among studies. CONCLUSION This systematic review revealed that the SRs and radiographic marginal bone loss of flapless intervention were comparable with the flap surgery approach.

Retrograde Peri-Implantitis: A Case Report Introducing an Approach to Its Management

BACKGROUND Although several potential etiologic factors associated with retrograde peri-implantitis (RPI) and potential treatment options have been discussed in the literature, the etiology has not been fully investigated and the definitive management methods remain undefined. We propose a decision-making protocol for the treatment of RPI and provide new insight into the etiology of this process based on the findings from two clinical cases. METHODS The medical and dental histories of two patients who developed RPI were thoroughly reviewed. Both patients were treated according to the treatment guidelines proposed in this manuscript. Fluid from the lesions was collected to examine the presence of 11 bacterial species by molecular-based microbial testing. Biopsies were also obtained for histopathologic examination. RESULTS Patient 1, previously diagnosed with human immunodeficiency virus infection, developed RPI 3 months after implant placement. Histopathologic examination revealed a predominantly fibrous connective tissue response with minimal inflammatory infiltrate and bone formation. Patient 2 presented histopathologically with an intense acute inflammatory response. Eikenella corrodens was detected by microbial testing. Three months after surgical intervention, both cases healed uneventfully, and the radiodensity in the lesions significantly increased. The two implants are now functional and free of further complications. CONCLUSIONS The possible role of bacterial infection from an adjacent tooth may be a potential etiologic factor in the development of RPI. In addition, HIV infection may be associated with RPI and deserves further investigation. A decision-making flowchart was proposed after critically evaluating the currently available relevant literature. Both cases presented in this manuscript were successfully treated by following this protocol.

Effect of Bisphosphonates on Anodized and Heat-Treated Titanium Surfaces: An Animal Experimental Study

BACKGROUND Recent investigations reported that osseointegration of titanium implants can be significantly reinforced with a nanostructure treated with anodic oxidation and heat treatment. This experimental study investigates the effect of bisphosphonates on the nanotubular implant surface in rats. METHODS Thirty-six titanium implants were divided into three groups: 1) machine-turned (MT), 2) anodized and heat-treated (AH), and 3) anodized and heat- and bisphosphonate-treated (AHB) groups. The 36 implants were randomly placed in both tibias of 18 male Wistar rats. After 2 and 4 weeks, the levels of osseointegration of the implants were evaluated by a removal torque test and microcomputerized tomography (μCT). Peri-implant bone tissue on the extracted region was examined for the expression of type I collagen and osteocalcin. RESULTS The AHB group showed the highest removal torque at 2 and 4 weeks (13.92 ± 1.51 Ncm and 18.10 ± 2.15 Ncm, respectively) followed, in order, by the AH group (11.63 ± 1.58 Ncm at 2 weeks and 14.80 ± 2.34 Ncm at 4 weeks) and MT group (4.30 ± 0.76 Ncm at 2 weeks and 6.20 ± 1.33 Ncm at 4 weeks) with statistically significant differences between the MT and other two groups at both time points. μCT images also revealed a denser appearance around implants in the AHB group than in the other groups. Levels of type I collagen and osteocalcin expression were similar between the MT and AH groups; however, the values were significantly higher in the AHB group compared to the other groups, which were 220.85% ± 71.09% and 363.04% ± 100.21%, respectively (P <0.05). CONCLUSION Within the limits of this experiment, it was concluded that surface loading with bisphosphonates significantly improved the degree of osseointegration of titanium implants with a nanostructure.

Updated Clinical Considerations for Dental Implant Therapy in Irradiated Head and Neck Cancer Patients

An increasing number of reports indicate successful use of dental implants (DI) during oral rehabilitation for head and neck cancer patients undergoing tumor surgery and radiation therapy. Implant-supported dentures are a viable option when patients cannot use conventional dentures due to adverse effects of radiation therapy, including oral dryness or fragile mucosa, in addition to compromised anatomy; however, negative effects of radiation, including osteoradionecrosis, are well documented in the literature, and early loss of implants in irradiated bone has been reported. There is currently no consensus concerning DI safety or clinical guidelines for their use in irradiated head and neck cancer patients. It is important for health care professionals to be aware of the multidimensional risk factors for these patients when planning oral rehabilitation with DIs, and to provide optimal treatment options and maximize the overall treatment outcome. This paper reviews and updates the impact of radiotherapy on DI survival and discusses clinical considerations for DI therapy in irradiated head and neck cancer patients.

Effect of Flapless Surgery on Single-Tooth Implants in the Esthetic Zone: A Randomized Clinical Trial

BACKGROUND Implant therapy is a highly predictable treatment option; however, insufficient data exist to show whether flapless implant surgery provides better esthetic outcomes and less bone loss than implant surgery with a flap approach. METHODS In this randomized, controlled study comparing the flapless and traditional flap protocol for implant placement, 24 patients received a single implant in the anterior maxillary region. A cone beam computed tomography-aided surgical guide was used for implant placement surgery for both groups. Implants were restored using a one-piece, screw-retained ceramic crown at 3 months. Radiographic and clinical measurements were assessed at baseline (implant placement) and at 3 (crown placement), 6, 9, and 15 months. Clinical parameters evaluated were plaque index, gingival index, papillary index (PPI) (0 = no papilla, 1 = less than half, 2 = more than half but not complete, 3 = complete fill, and 4 = overfill), marginal tissue levels, biotype, width of keratinized tissue, and soft tissue thickness. RESULTS Implant success rate was 92% in both groups. Mean PPI values for the flap control group and flapless test group were 2.38 ± 0.51 versus 2.31 ± 0.48 at crown placement (P = 0.68) and 2.52 ± 0.52 versus 2.64 ± 0.54 at 15 months (P = 0.42), respectively. PPI increased over time in both groups, although the flapless group had a significantly larger change in PPI from crown placement to 6 and 9 months (P <0.01). Crestal bone levels in the flap group were more apical in relation to the implant platform than those in the flapless group for the duration of the study. No differences among groups were noted for all other measurements. CONCLUSIONS Both flapless and flap implant placement protocols resulted in high success rates. A flapless protocol may provide a better short-term esthetic result, although there appears to be no long-term advantage.

Significance of the epithelial collar on the subepithelial connective tissue graft.

BACKGROUND Most clinicians adopt two versions of the subepithelial connective tissue graft (SCTG) procedure, SCTG with or without the epithelial collar on the graft combined with a coronally advanced flap (CAF). However, limited evidence is available to determine whether a retained epithelial collar on an SCTG is needed for a better outcome. The goal of this study was to compare the clinical outcomes of the two SCTG techniques (i.e., SCTG with or without an epithelial collar). METHODS Twenty patients with Miller Class I or II gingival defects >/=2.0 mm were recruited for the study. The patients were randomly assigned to receive an SCTG with a retained epithelial collar + CAF (SCTGE; n = 10) or an SCTG without an epithelial collar + CAF (SCTGN; n = 10). Clinical parameters, including recession depth, recession width (RW), width of keratinized gingiva (KW), clinical attachment level (CAL), probing depth (PD), gingival index (GI), and plaque index (PI), were assessed at baseline and 3 and 6 months after surgery. RESULTS SCTGE and SCTGN groups exhibited significant root coverage at 3 and 6 months compared to baseline (P <0.05). The SCTGE group had mean root coverage of 97.50% +/- 7.90% at 6 months compared to 89.10% +/- 25.93% in the SCTGN group, with no significant difference between the groups. At 6 months, complete root coverage was seen in nine of 10 and seven of 10 subjects from SCTGE and SCTGN groups, respectively. Mean KW at 3 months for the SCTGE group was 4.10 +/- 1.10 mm, whereas in the SCTGN group it was 2.75 +/- 0.68 mm. Mean RW was 0 mm and 1.20 +/- 1.60 mm for SCTGE and SCTGN groups, respectively. KW and RW were statistically significantly different between the two groups at 3 months; however, this significance was not seen at 6 months. Other clinical parameters (CAL, PD, thickness of the recipient gingival tissue, PI, GI, and the wound healing index) showed no significant differences between the groups at any time point. CONCLUSIONS Both SCTG techniques (with or without the epithelial collar) provided predictable and successful root coverage (>/=89%). This study suggests that a retained epithelial collar on the SCTG may not provide a significant benefit with regard to clinical parameters.

Outcomes of regenerative treatment with rhPDGF-BB and rhFGF-2 for periodontal intra-bony defects: a systematic review and meta-analysis.

BACKGROUND The aim was to evaluate the effects of recombinant human platelet-derived growth factor-BB (rhPDGF-BB) and recombinant human fibroblast growth factor-2 (rhFGF-2) on treating periodontal intra-bony defects, compared to the control (carrier alone). METHODS Electronic and hand searches were performed to identify eligible studies. The weighed mean differences of linear defect fill (LDF), probing depth (PD) reduction, clinical attachment level (CAL) gain and gingival recession (GR) were calculated using random effect meta-analysis. RESULTS The searches yielded 1018 articles, of which seven studies were included. Only one included study was considered at low risk of bias. The outcomes that reached statistical significance in comparison to carriers alone included: LDF (0.95 mm, 95% CI: 0.62-1.28 mm or 20.17%, 95% CI: 11.81-28.54%) and CAL gain (0.34 mm, 95% CI: 0.03-0.65 mm) for PDGF, and LDF (21.22%, 95% CI: 5.82-36.61%) for FGF-2. CONCLUSIONS Within the limits of this review, rhPDGF-BB demonstrated significantly more LDF and CAL gain; rhFGF-2 resulted in significantly higher percentage of LDF.