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Browsing by Author "Hamada, Yusuke"
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Item Amnion–Chorion Allograft Barrier Used on Root Surface for Regenerative Procedures: Case Report(Wiley, 2020-12) Hamada, Yusuke; Yeh, Yu-Ting; Blanchard, Steven B.; Periodontology, School of DentistryIntroduction Guided tissue regeneration (GTR) has been well documented with combination of bone graft substitutes and biologic modifiers to improve the outcomes of periodontal regenerative procedures. Amnion-chorion allograft membrane (ACM) is a placenta-derived resorbable allograft membrane which contains growth factors found in the placenta. The primary purpose of the barrier membranes for GTR was to exclude the epithelial down-growth along with the root surface, however, the ACM can be used as an additional biologic modifier because of the release of growth factors from the ACM after placement. The aim of this case report is to evaluate the efficacy and the application of ACM on the previously diseased root surface to treat periodontal intrabony defect. Case Presentation A 60-year-old Caucasian male with deep and wide intrabony defect on mesial #19 was treated with a regenerative procedure with combination of application of ACM on the root surface and filling the intrabony defect with the corticocancellous freeze-dried bone allograft. The bone substitute was covered with another layer of ACM and primary closure was achieved. Wound healing process was uneventful, and the clinical and radiographic outcomes were favorable up to 18 months after the surgical procedure. Conclusion This case report demonstrated that the application of ACM on the root surface with a combination of bone substitute might enhance to the radiographic bone fill and the clinical attachment level gain and minimize the risk of post-operative gingival recession.Item The Application of a CO2 Laser in Implant Site Development: A Case Report(2019) Villanueva, Justin; Blanchard, Steven B.; Hamada, Yusuke; Periodontology, School of DentistryIntroduction: Ridge preservation procedures have been utilized to minimize the alveolar ridge dimensional changes following tooth extraction. This case report describes a novel approach to ridge preservation with an application of a carbon dioxide laser (CO2 laser) to stabilize blood clot formation and stimulate wound healing. Case presentation: A 76-year-old Caucasian male with history of type 2 diabetes was referred for extraction of #8 and placement of a dental implant to reconstruct the area. Extraction was performed in a minimal traumatic manner and a mineralized freeze-dried bone allograft was placed in the socket. A 10,600 nm wavelength CO2 laser was used in setting of 1.0 watts focused continuous wave energy to stabilize the blood clot over the extraction site. The laser was used until a char layer was formed. This char layer was a non-bleeding stable blood clot, and the end-point of laser application was set as “no blood flow from the clot are within 10 seconds.” No membranes or sutures were used. Eleven weeks after the extraction and ridge preservation, a 4.1x10mm dental implant was placed with >35N/cm of primary stability and Implant stability quotient (ISQ) value of 83. A provisional crown was delivered at the time of implant placement. Three months following implant placement, the final restoration was delivered. The soft and hard tissue healing were uneventful to achieve esthetic and functional outcomes. Conclusion: Within limits of this case report, the application of CO2 laser for “Laser-Assisted Blood Clot Formation” may enhance the soft and hard tissue healing following extraction for ridge preservations.Item Assessing Effectiveness of an Audiovisual Educational Tool for Improving Dental Students' Probing Depth Consistency(Wiley, 2019-04) Prabhu, Srividya; John, Vanchit; Blanchard, Steven; Eckert, George J.; Hamada, Yusuke; Periodontology, School of DentistryDental students often underestimate their probing depth (PD) measurements, which emphasizes the need for effective and novel methods for teaching proper probing technique. The aim of this study was to evaluate the efficacy of audiovisual learning aids, recorded from the point of view of examiners, for improvement in PD agreement in dental students. In 2017‐18, 22 third‐year dental students were randomized into test and control groups. Each student and a single blinded faculty examiner performed PD measurements on a minimum of three patients. The test group viewed a video demonstrating proper probing technique, while the control group received only probing technique instruction from prior lectures. All measurements, the periodontal diagnoses, and the total time taken to complete PD measurements were recorded. A survey of student attitudes about the audiovisual tool was conducted after the intervention; all 22 students completed the survey. A total of 11,426 PD sites were measured. The test group had 10% greater accuracy in PD sites=4 mm. The control group had a minor but statistically significant increase in accuracy for 2 mm PD sites. For all incorrect measurements at sites PD≥4, the students tended to underestimate the PD. Tooth type, site location around tooth, and diagnosis had no significant effect on PD measurement agreement. No significant difference between groups was found for the proportions of gingivitis and periodontitis patients or for examination time. This study found that use of the audiovisual learning aid “Calibrated Periodontal Training Video” improved the students' probing depth accuracy for sites with PD of 4 mm.Item Assessing the Medical Emergency Preparedness of Dental Faculty, Residents, and Practicing Periodontists: An Exploratory Study(ADEA, 2018-05) de Bedout, Tatiana; Kramer, Kyle; Blanchard, Steven; Hamada, Yusuke; Eckert, George J.; Maupome, Gerardo; John, Vanchit; Oral and Maxillofacial Surgery and Hospital Dentistry, School of DentistryWith the increased number of elderly and medically compromised individuals receiving dental care and the presence of systemic comorbidities and associated treatment modalities in this patient population, it is imperative that dentists be prepared to manage a variety of medical emergencies. The aim of this study was to assess the knowledge of and preparedness to manage common medical emergencies of cohorts of practicing periodontists, specialty residents, and faculty members, both for comparative purposes and as an aid to refining a dental school’s standardized case scenarios. The study, conducted in 2017, was designed for four groups of randomly selected participants with at least 20 in each group; the actual number of voluntary participants was 28 private practice periodontists, 22 residents in specialty programs, 21 specialist faculty members, and 24 general practice faculty members. Participants were asked to evaluate ten clinical emergency cases and identify the diagnosis and indicated intervention for each. Groups were also evaluated for differences among correct responses for each case. Overall, there were no statistically significant differences for number of correct diagnoses or interventions among the four groups. However, several cases had varying degrees of incorrect diagnoses and management across all groups. Participants who had recently graduated or were still in school were able to treat cases appropriately more often than the other participants. Further refinement of cases to assess provider preparedness to correctly diagnose and manage medical emergencies is needed, specifically establishing case-specific features and addressing areas of potential confusion before the cases are used for educational purposes.Item Association between intracranial carotid artery calcifications and periodontitis: A cone-beam computed tomography study(AAP, 2021-10) AlSakr, Abdulaziz; Blanchard, Steven; Wong, Phillip; Thyvalikakath, Thankam; Hamada, Yusuke; Periodontology, School of DentistryBackground Intracranial carotid artery calcifications (ICACs) are one type of calcification that may be detected as incidental findings in cone-beam computed tomography (CBCT). This retrospective study aimed to examine the prevalence of ICACs on CBCT images and their associations among age, gender, chronic periodontitis, and patient-reported cardiovascular diseases (CVDs). Methods A total of 303 CBCT scans were reviewed and a total of 208 patients met the inclusion criteria. The presence or absence of ICACs was evaluated in the ophthalmic and cavernous segments of each scan. Patient demographic data, including age, gender, and medical history, specifically focused on CVDs were recorded. The presence or absence of periodontitis was recorded from each subject with full mouth radiographs and clinical measurements. Odds ratios (ORs) were calculated as part of the logistic regression analysis. Results Overall, ICACs were found in 93 subjects (45%). The bilateral ICACs were found in 43 subjects (21% of the total subjects, 46% of the subjects with ICACs). There were statistically significant associations between presence of ICACs and periodontitis (OR = 4.55), hypertension (OR = 3.02), hyperlipidemia (OR = 2.87), increasing age (OR = 2.24), and the male gender (OR = 1.85). Smoking status was not significantly correlated with ICACs. Conclusion This study revealed that nearly half (45%) of the subjects displayed ICACs on the CBCT images. ICACs are significantly related to the status of chronic periodontitis, age, gender, and CVDs. A more careful review of CBCT scans is highly recommended to detect these calcifications and refer patients for further medical evaluation.Item Biomechanical and histological evaluation of a new zirconia implant in a canine model(2015) Hamada, Yusuke; Chu, Tien-Min Gabriel; Prakasam, Sivaraman; Zunt, Susan L.; Liu, Sean Shih-Yao; Blanchard, StevenBackground: Currently titanium implant fixtures are considered as a gold standard because of their biocompatibility and their clinical success rates have been well documented. The esthetic outcome of restorations supported by titanium implants may be compromised if the dark gray color of the implant shows through a thin peri-implant mucosa or if the implant fixture becomes visible following soft tissue recession. Also titanium might cause allergic reactions. For these reasons, zirconia implants have been considered as alternative materials because of their white color, high material properties and biocompatibilities. Still, further investigations are necessary to confirm the in-vivo performance of these implants. Purpose: The purpose of this study is to determine the histomorphometric and biomechanical properties of zirconia implants manufactured by Shofu Inc. with a sand-blasted and acid-etched surface treatment, compared to that of the titanium implants from the same manufacturer with a sand-blasted and acid-etched surface treatment in a canine model. Material and Methods: Six beagle dogs (1-2 years old) will be used in this split mouth trial. After 8 weeks following extraction of the second to fourth mandibular premolars, zirconia implants (experimental group) and titanium implants (control group) were placed on the each side of mandible. At 8 weeks and 12 weeks after implant placement, the animals were sacrificed, and implants were removed in block sections, and histological and histomorphometric analyses were measured. Specifically, the bone-implant contact (BIC), bone area (BA), removal torque (RTQ), mineral apposition rate (MAR), bone forming area (BFA), and Periotest value (PTV) of the two groups were studied and compared. Results: At 12 weeks post operatively, one Shofu thread type Ti implant were not integrated. Over all failure implant was 0/12 in zirconia group, and 1/12 in titanium group. In 8 weeks samples, only statistical differences were higher BA (p=0.02) in macro threads area and BFA (p=0.02) in zirconia implants group than titanium implants group. In 12 weeks group, zirconia implant group showed higher MAR at 9-10 and 10-11weeks time frame (p=0.02, and 0.04 restectively), and PVT value (p=0.01) than titanium implants group. Removal torque value increased in both titanium and zirconia group with time. Average of removal torque value showed higher in titanium implants than zirconia implants, but the differences were not statistically significant in both 8 weeks (Ti; 64.16±16.93 N-cm, ZrO₂: 42.5±6.01 N-cm : p=0.247) and 12 weeks (Ti; 82.5±9.41 N-cm, ZrO₂: 51.3±19.38 N-cm: p=0.16). In the removal torque analysis, it is observed that the bone-implant interface seems to be of more rigid and brittle in nature as indicated by the lower averaged onset angle, peak angle, area under curve and RTQ. Conclusion: Zirconia implants group showed higher value of BA with macro thread and BFA in 8weeks and MAR at 9-10, 10-11 weeks period, and PVT in 12 weeks post operatively. Within the limited number of samples tested in this study, there is no difference between the BIC and RTQ of zirconia and titanium implants after 8 and 12 weeks of implantation.Item Canine impaction – A review of the prevalence, etiology, diagnosis and treatment(Elsevier, 2019-06) Hamada, Yusuke; Timothius, Celine Joyce Cornelius; Shin, Daniel; John, Vanchit; Periodontology, School of DentistryThe signs and symptoms of canine impaction can vary, with patients only noticing symptoms when they are suffering from unsightly esthetics, faulty occlusion, or poor cranio-facial development. While various surgical interventions have been proposed to expose and help erupt impacted canines, these treatment modalities have a high degree of difficulty compared to other types of dental cosmetic surgeries. This paper focuses on multi-disciplinary strategies for treating and managing canine impaction, reviews patient and clinical selection criteria, and discusses the evidence underlying existing interventions to reduce complications and improve patient-centered outcomes following treatment.Item Differential profiles of soluble and cellular toll like receptor (TLR)-2 and 4 in chronic periodontitis(PLOS, 2018-12-20) AlQallaf, Hawra; Hamada, Yusuke; Blanchard, Steven; Shin, Daniel; Gregory, Richard; Srinivasan, Mythily; Periodontology, School of DentistryChronic periodontitis is a common inflammatory disease initiated by a complex microbial biofilm and mediated by the host response causing destruction of the supporting tissues of the teeth. Host recognition of pathogens is mediated by toll-like receptors (TLRs) that bind conserved molecular patterns shared by large groups of microorganisms. The oral epithelial cells respond to most periodontopathic bacteria via TLR-2 and TLR-4. In addition to the membrane-associated receptors, soluble forms of TLR-2 (sTLR-2) and TLR-4 (sTLR-4) have been identified and are thought to play a regulatory role by binding microbial ligands. sTLR-2 has been shown to arise from ectodomain shedding of the extracellular domain of the membrane receptor and sTLR-4 is thought to be an alternate spliced form. Many studies have previously reported the presence of elevated numbers of viable exfoliated epithelial cells in the saliva of patients with chronic periodontitis. The objective of this study was to investigate the potential value of salivary sTLR-2 and sTLR-4 together with the paired epithelial cell-associated TLR-2/4 mRNA as diagnostic markers for chronic periodontitis. Unstimulated whole saliva was collected after obtaining informed consent from 40 individuals with either periodontitis or gingivitis. The sTLR-2 and sTLR4 in saliva was measured by enzyme-linked immunosorbent assay. The TLR-2 and TLR-4 transcript in the epithelial cells in saliva was measured by real time polymerase chain reaction. While levels of sTLR-2 exhibited an inverse correlation, sTLR-4 positively correlated with clinical parameters in the gingivitis cohort. Interestingly, both correlations were lost in the periodontitis cohort indicating a dysregulated host response. On the other hand, while the sTLR-2 and the paired epithelial cell associated TLR-2 mRNA exhibited a direct correlation (r2 = 0.62), that of sTLR4 and TLR-4 mRNA exhibited an inverse correlation (r2 = 0.53) in the periodontitis cohort. Collectively, assessments of salivary sTLR2 and sTLR4 together with the respective transcripts in the epithelial cells could provide clinically relevant markers of disease progression from gingivitis to periodontitis.Item Differential profiles of soluble and cellular toll like receptor (TLR)-2 and 4 in chronic periodontitis(PLOS, 2018-12-20) AlQallaf, Hawra; Hamada, Yusuke; Blanchard, Steven; Shin, Daniel; Gregory, Richard; Srinivasan, Mythily; Periodontology, School of DentistryChronic periodontitis is a common inflammatory disease initiated by a complex microbial biofilm and mediated by the host response causing destruction of the supporting tissues of the teeth. Host recognition of pathogens is mediated by toll-like receptors (TLRs) that bind conserved molecular patterns shared by large groups of microorganisms. The oral epithelial cells respond to most periodontopathic bacteria via TLR-2 and TLR-4. In addition to the membrane-associated receptors, soluble forms of TLR-2 (sTLR-2) and TLR-4 (sTLR-4) have been identified and are thought to play a regulatory role by binding microbial ligands. sTLR-2 has been shown to arise from ectodomain shedding of the extracellular domain of the membrane receptor and sTLR-4 is thought to be an alternate spliced form. Many studies have previously reported the presence of elevated numbers of viable exfoliated epithelial cells in the saliva of patients with chronic periodontitis. The objective of this study was to investigate the potential value of salivary sTLR-2 and sTLR-4 together with the paired epithelial cell-associated TLR-2/4 mRNA as diagnostic markers for chronic periodontitis. Unstimulated whole saliva was collected after obtaining informed consent from 40 individuals with either periodontitis or gingivitis. The sTLR-2 and sTLR4 in saliva was measured by enzyme-linked immunosorbent assay. The TLR-2 and TLR-4 transcript in the epithelial cells in saliva was measured by real time polymerase chain reaction. While levels of sTLR-2 exhibited an inverse correlation, sTLR-4 positively correlated with clinical parameters in the gingivitis cohort. Interestingly, both correlations were lost in the periodontitis cohort indicating a dysregulated host response. On the other hand, while the sTLR-2 and the paired epithelial cell associated TLR-2 mRNA exhibited a direct correlation (r2 = 0.62), that of sTLR4 and TLR-4 mRNA exhibited an inverse correlation (r2 = 0.53) in the periodontitis cohort. Collectively, assessments of salivary sTLR2 and sTLR4 together with the respective transcripts in the epithelial cells could provide clinically relevant markers of disease progression from gingivitis to periodontitis.Item Effects of platelet‐rich fibrin on human gingival and periodontal ligament fibroblast proliferation from chronic periodontitis versus periodontally healthy subjects(Wiley, 2021-08) Goel, Apoorv; Windsor, L. Jack; Gregory, Richard L.; Blanchard, Steven B.; Hamada, Yusuke; Periodontology, School of DentistryBackground: Platelet-rich fibrin (PRF), an autogenous blood concentrate, contains multiple growth factors and is used as an adjunct in the periodontal regeneration and implant site development procedures to stimulate wound healing. Patient-related factors such as chronic periodontitis may affect the quality of PRF. Objectives: This study aimed to investigate and compare PRF's effects from patients diagnosed with generalized moderate or severe chronic periodontitis to patients who presented with intact periodontium on human gingival fibroblast (HGF) and human periodontal ligament fibroblast (HPLF) proliferation. Materials and methods: A total of 33 ml of whole intravenous blood was collected from each subject and centrifuged at 2700 rpm for 12 min in three 10 ml tubes, and 3 ml of blood was used for Complete Blood Count analysis. Three PRF clots were compressed to produce the membranes and liquid exudate. PRF membrane and 10% liquid exudate were exposed to 20,000 HPLFs/well or 25,000 HGFs/well in triplets from each subject in a 48 cell well plate. After 72 h of incubation, the conditioned media were evaluated by Water Soluble Tetrazolium-1 assays to determine fibroblast proliferation. Controls included cells alone and media without cells. Complete blood counts were measured. Results: Subjects in both groups were age and gender-matched (intact 46.7 ± 11.4 years and periodontitis 54.8 ± 10.4 years, p-value = 0.1344). Body Mass Index and White Blood Corpuscles in the periodontitis group was significantly higher than the intact group (p = 0.0176 and p = 0.0038) whereas no differences were seen for Red Blood Corpuscles (p = 0.2020), Hemoglobin (p = 0.2290) and Platelets (p = 4,094). There were no significant differences in the HGF and HPLF proliferation with PRF exudates and membranes between intact periodontium and periodontitis groups (all p > 0.05). However, PRF exudates in both groups induced significant more cell proliferation when compared to PRF membranes. Conclusions: PRF exudates induced significant proliferation of fibroblasts and can play a vital role in wound healing. The current study concluded that PRF membranes, in combination with PRF exudates, can be utilized for their therapeutic and wound healing potential, not affected by the periodontal condition of the patient.