Biomedical subjects

Hom-Lay Wang

Publications and source records attributed to Hom-Lay Wang.

At least 37 records · Page 2Linked to original sources

PubMed2006

Utilization of mandibular tori for alveolar ridge augmentation and maxillary sinus lifting: a case report.

This article reports the utilization of mandibular tori as an alternative source of autogenous bone for ridge augmentation and maxillary sinus lifting to facilitate ideal implant placement. A patient presenting bilateral mandibular tori required replacement of a missing maxillary molar and a mandibular premolar. Both areas showed ridge deficiency that required bone augmentation before implant placement. Mandibular tori were used for horizontal augmentation of the mandibular alveolar ridge and vertical augmentation of the maxillary ridge by elevation of the maxillary sinus. Adequate new bone formation was noted in both areas 6 months after grafting. Bone formed in the grafted areas showed comparable clinical features to those of native bone. Implants were successfully placed and loaded, restoring esthetics and function. Within the limitations of this observation, mandibular tori can be successfully used for ridge augmentation and sinus lifting. However, further controlled studies are needed to determine the overall benefit of this source of autogenous bone.

Adult↗

PubMed2006

Histologic analyses of human mineralized bone grafting material in sinus elevation procedures: a case series.

Human mineralized bone allograft is a solvent-preserved allograft and is therefore composed of a unique bone substitute that differs from other forms of bone allograft processed via standard cryopreservation. During solvent preservation, the mineral and collagen structures appear to remain intact, thus possibly facilitating bony ingrowth when the mineral is used as a bone graft. This case series illustrates the histologic and clinical effects of this bone graft material for sinus elevation procedures. Histology from bone biopsy core samples of four patients revealed newly formed bone with a well-organized lamellar bone structure in general, and in some cases, remaining particles were observed in contact with surrounding newly formed bone. Histomorphometric analysis demonstrated a mean of 73.3% of bone formation (range, 66.1% to 85.0%) in the grafted sites, resulting in bone density that was similar to that of the original host bone (mean, 73.2%; range, 64.4% to 84.8%). Clinically, no complications were observed, and all implants were considered clinically osseointegrated after 6 months (range, 4 to 8 months). The results of this study suggest that human mineralized bone allograft could be successfully used in sinus lifting procedures and encourage further research of this solvent-preserved bone allograft material in oral reconstruction for future implant placement.

Adult↗

PubMed2006

Association of periodontal disease severity with diabetes duration and diabetic complications in patients with type 1 diabetes mellitus.

OBJECTIVES: The association between periodontal disease severity and diabetes complications and duration in patients with type 1 diabetes mellitus (DM) was investigated in this comparative cross-sectional study. MATERIALS AND METHODS: Twenty-nine patients with type 1 DM of < or = 5 years duration were compared with 43 patients with > 5 years duration of DM. Complete medical history and examination and assessments of retinopathy, neuropathy, and nephropathy were performed, followed by assessments of the plaque index (PI), pocket depth (PD), clinical attachment level (CAL), and the number of missing teeth by one examiner masked to the diabetic status of the patients. RESULTS: The number of missing teeth (4 versus 0) and CAL (2.88 vs 2.56 mm) were significantly higher in patients with longer DM duration (p < 0.05). For patients with > or = 5 years DM duration, periodontal disease severity was also greater in patients with one or more DM complications, as assessed by the number of missing teeth (17 vs 0; p < 0.001) and CAL (4.74 vs 2.81 mm; p < 0.01). Stepwise multiple regression analysis associated the presence of > or = 1 DM complications and smoking history with severe attachment loss (CAL > or = 7 mm; p < 0.001). CONCLUSION: Periodontal disease severity is associated with both DM duration and the presence of DM complications in this sample of type 1 DM patients.

Adolescent↗

PubMed2006

Canine impactions: incidence and management.

Impacted teeth present many problems for the orthodontist. They can compromise tooth movement, esthetics, and functional outcomes. The second most commonly impacted tooth, after the maxillary third molar, is the maxillary canine, with an incidence from 1% to 2.5%. Maxillary canines can be impacted facially or palatally and are more common in female patients than in male patients. Therefore, the purpose of this paper is to address the incidence and etiology associated with impacted maxillary canines, the clinical and radiographic evaluation of the situation, and the techniques for managing this problem. Papers related to this topic were identified and reviewed thoroughly. A decision tree involving the various techniques employed to expose impacted canines is presented, together with methods used to identify the location of impacted canines. The impacted canine can be properly managed with proper diagnosis and technique.

Alveolectomy↗

PubMed2005

Dental implants for orthodontic anchorage.

The purpose of this article is to review and update current concepts involving the use of dental implants for orthodontic anchorage. Topics to be discussed include indications, implant requirements (eg, materials, size, designs of dental implants), surgery and healing time, biomechanics and forces, loading time, implant maintenance, posttreatment considerations, and disadvantages.

Bone Screws↗

PubMed2005

Periodontal regeneration techniques for treatment of periodontal diseases.

The ultimate goal of periodontal therapy is the regeneration of structures lost to disease. Conventional surgical approaches such as open-flap debridement offer only limited regeneration potential.Currently, surgical procedures for predictable regeneration of periodontal tissues are being developed, analyzed, and employed in clinical practice. This article addresses current trends in periodontal regeneration. Various materials/agents such as bone replacement grafts, barrier membranes, and biologic modifiers currently used for the regeneration of periodontal infrabony and furcation defects are discussed.

Alveolar Bone Loss↗

PubMed2005

Implant surgical guide fabrication for partially edentulous patients.

This article presents an innovative method for the fabrication of implant drill guides for partially edentulous patients. Using a light-polymerized composite material and drill blanks placed in the prosthodontically driven implant position, surgical guides for each implant drill are constructed on the diagnostic cast. In addition to the size-customized implant surgical guides, a ridge crest preparation guide showing the proposed crown contour is used to adjust the tissue contour, if needed, during implant surgery.

Composite Resins↗

PubMed2005

Comparison of linear tomography and direct ridge mapping for the determination of edentulous ridge dimensions in human cadavers.

OBJECTIVE: The purpose of this study was to compare the accuracy of linear tomography (LT) and direct ridge mapping (RM) for determining alveolar ridge dimensions. STUDY DESIGN: One site in the posterior mandible was selected for evaluation in each of 5 cadaver heads. Vacuum-formed stents made from models of the cadaver ridges were used to identify 3 sets of measurement points for each specimen: coronal (intersection of coronal and middle third of ridge), middle (intersection of middle and apical third), and apical (base of vestibule). The imaging stent contained 2-mm metal balls at each point, while the RM stent had holes drilled at corresponding locations. Linear tomograms and periapical radiographs (PA) were taken of the selected sites. RM measurements were made with calipers. Five blinded examiners measured ridge width at the designated measurement points with both LT and RM as well as distance from the ridge crest to mandibular canal (using PAs for RM group). Mandibles were then sectioned and an independent examiner made direct measurements (DM). MANOVA was used to determine whether LT and RM differed significantly from DM. RESULTS: There were no significant differences between LT and RM for ridge width measurements. However, both techniques underestimated ridge dimensions compared to DM ( P < .05). Measurement of mandibular canal height was accurate when determined by periapical radiographs but not by LT. CONCLUSION: Neither LT nor RM proved to be completely accurate in determining ridge width in the posterior mandible.

Alveolar Process↗

PubMed2005

Multidisciplinary treatment approach for enhancement of implant esthetics.

A "team approach" that includes different specialties from the initial stages of implant treatment is important to achieve predictable and esthetically pleasing outcomes in compromised dental replacement cases. This report describes a severely compromised case that was properly managed by the combined efforts of a team of specialists. Briefly, prior to tooth extraction, orthodontic forced eruption was applied to coronally displace the attachment apparatus (i.e., hard and soft tissues). Then, atraumatic tooth extraction together with immediate implant placement was performed. The "sandwich bone augmentation" technique was used to augment the deficient buccal alveolar ridge. A second stage surgery was performed 6 months after healing, revealing 100% of bone fill/augmentation. This technique allowed fabrication of a final restoration that respected the proportions of the natural dentition in a case that would otherwise result in a poor esthetic outcome.

Adult↗

PubMed2005

Factors associated with implant recommendation for single-tooth replacement.

The use of dental implants for single-tooth replacement has been established as a predictable treatment option; yet, limited data are available as to how frequently this option is recommended to patients. The aim of the present study was to examine the frequency of implant recommendation by general dental practitioners after single-tooth extraction and factors influencing their decision to recommend an implant. All single-tooth extractions performed in 26 general dental practice clinics in Kuwait over a 30-day period were examined. Dentists in these centers used the study form to record demographic data, the type of tooth extracted, reason for extraction, and replacement options presented to the patients. Univariate and logistic regression analyses were used to examine associations between background factors and decisions to recommend implant therapy. A total of 1367 patients (mean age, 37.9 +/- 11.8 years) had an extraction of one tooth during the study period. Forty-three patients were offered implants as a replacement option (3.3% of the total sample; 8.6% of patients who were offered tooth replacement options). Factors associated significantly with the recommendation of an implant by Kuwaiti dentists to their patients included younger age, regular dental maintenance visits, and adequate oral hygiene practices (P < 0.05; binary logistic regression). Dental implant recommendation for single-tooth replacement in the present sample of dentists was low. Factors associated significantly with dentist recommendation of an implant for single-tooth replacement included age, history of dental maintenance, and oral hygiene practices.

Adolescent↗

PubMed2005

Implant reversible complications: classification and treatments.

Failures of dental implants are detrimental to both patients and dental providers. These failures are often preceded by complications at various levels of the treatment phases. Early detection of the complications that are amenable to rescue therapies may reverse the fate of the implant. This review article discusses diagnosis, classification, and treatment aspects of the reversible complications commonly encountered during routine dental implant-related procedures.

Dental Abutments↗

PubMed2005

Mucogingival pouch flap for sandwich bone augmentation: technique and rationale.

This article introduces a novel flap design, mucogingival pouch flap (MPF), to enhance the clinical outcome of sandwich bone augmentation. MPF uses a pouch flap reflection via mucogingival junction extension incisions to provide an improved graft retention, minimized membrane exposure, preserved papilla dimension, and soft tissue camouflage for improved esthetics. There are 4 implant-associated buccal dehiscence defects in 3 patients treated with sandwich bone augmentation technique in conjunction with MPF. All cases yielded an adequate new bone thickness of 1.5-3.5 mm as well as a height of 84% to 100% at 6 months. Rationales, indications, contraindications, advantages, and disadvantages for MPF designs are further discussed.

Adult↗

PubMed2005

Occlusal considerations in implant therapy: clinical guidelines with biomechanical rationale.

Due to lack of the periodontal ligament, osseointegrated implants, unlike natural teeth, react biomechanically in a different fashion to occlusal force. It is therefore believed that dental implants may be more prone to occlusal overloading, which is often regarded as one of the potential causes for peri-implant bone loss and failure of the implant/implant prosthesis. Overloading factors that may negatively influence on implant longevity include large cantilevers, parafunctions, improper occlusal designs, and premature contacts. Hence, it is important to control implant occlusion within physiologic limit and thus provide optimal implant load to ensure a long-term implant success. The purposes of this paper are to discuss the importance of implant occlusion for implant longevity and to provide clinical guidelines of optimal implant occlusion and possible solutions managing complications related to implant occlusion. It must be emphasized that currently there is no evidence-based, implant-specific concept of occlusion. Future studies in this area are needed to clarify the relationship between occlusion and implant success.

Biomechanical Phenomena↗

PubMed2005

Management of inter-dental/inter-implant papilla.

OBJECTIVES: The aims of this paper are to review and compare existing techniques for creation of interdental/interimplant papillae, to address factors that may influence its appearance and to present an approach that authors developed that could help clinicians to manage and recreate the interproximal papillae. METHODS: Papers related to interdental and interimplant papillae published over the last 30 years were selected and analyzed. RESULTS: Thorough treatment planning is essential for maintenance of the height of the interproximal papillae following tooth removal. The key for achieving an esthetically pleasing outcome is the clinicians' ability of properly managing/creating interdental/interimplant papillae. Bone support is the foundation for any soft tissue existence, techniques such as socket augmentation, orthodontic extrusion, guided bone regeneration, onlay graft and distraction osteogenesis are often used for this purpose. Soft tissue grafts as well as esthetic mimic restorations can also be used to enhance the esthetic outcomes. CONCLUSIONS: An esthetic triangle is developed to address the foundations that are essential for maintaining/creating papilla. These include adequate bone volume, proper soft tissue thickness as well as esthetic appearing restorations.

Alveolar Bone Loss↗

PubMed2005

Biological foundation for periodontitis as a potential risk factor for atherosclerosis.

OBJECTIVES: Links between periodontal diseases and systemic diseases have been well documented by epidemiological studies. Recently, research has shifted to elucidating the biologic mechanism for a causal relationship. One focus of interest is atherosclerosis, the underlying event of cardiovascular diseases due to its serious health impact. However, it is still not clear whether periodontopathic pathogens are truly etiologic agents or ubiquitous bystanders. This article reviews the current understanding about the molecular biological interactions between periodontal disease and atherosclerosis and the biological plausibility of periodontitis as a potential risk factor for cardiovascular disease. MATERIALS AND METHODS: The current literature regarding periodontal diseases and atherosclerosis and coronary vascular disease was searched using the Medline and PubMed databases. RESULTS: In vitro experiments and animal models are appropriate tools to investigate the biological interactions between periodontal disease and atherosclerosis at the cell molecular level. The concepts linking both pathologies refer to inflammatory response, immune responses, and hemostasis. In particular, Porphyromonas gingivalis appears to have unique, versatile pathogenic properties. Whether or not these findings from isolated cells or animal models are applicable in humans with genetic and environmental variations is yet to be determined. Likewise, the benefit from periodontal therapy on the development of atherosclerosis is unclear. Approaches targeting inflammatory and immune responses of periodontitis and atherosclerosis simultaneously are very intriguing. CONCLUSION: An emerging concept suggests that a pathogenic burden from different sources might overcome an individual threshold culminating in clinical sequela. P. gingivalis contributes directly and indirectly to atherosclerosis.

Arteriosclerosis↗

PubMed2005

Factors affecting the outcomes of coronally advanced flap root coverage procedure.

BACKGROUND: The coronally advanced flap (CAF) has been used to treat gingival recession. However, the final outcomes (percentage of root coverage) vary from case to case. Hence, the purpose of this study was to analyze the factors that may affect the results of CAF root coverage procedures. METHODS: Twenty-three systemically healthy patients (mean age, 43.8 +/- 11.9 years) each with one Miller's Class I buccal recession defect were included. Baseline clinical parameters included recession depth (RD), recession width (RW), gingival thickness (GT), width of keratinized tissue (WKT), clinical attachment level (CAL), probing depth (PD), plaque index (PI), and gingival index (GI). CAF root coverage procedures were performed to correct the recession defects. Patients were followed at 2, 4, 12, and 24 weeks post-surgery, at which time wound healing index (WHI) and other measurements were recorded. RESULTS: The mean baseline RD was 2.9 +/- 0.4 mm; RW, 3.4 +/- 0.6 mm; WKT, 2.7 +/- 1.3 mm; and GT, 1.1 +/- 0.3 mm. At mid-buccal, the mean CAL was 4.5 +/- 0.8 mm. Six months after surgery, the average RC was 82.3% +/- 24.7%; RD, 0.5 +/- 0.7 mm; RW, 0.4 +/- 0.9 mm; WKT, 3.2 +/- 0.9 mm; and GT, 1.5 +/- 0.5 mm. At mid-buccal, the mean CAL was 1.8 +/- 1.1 mm. From baseline to the 6-month follow-up, the changes of RC, RD, RW, WKT, GT, and CAL showed statistical significance (P < 0.05). Fourteen patients achieved 100% RC. The mean RC in partial coverage cases was 54.8% +/- 16.8%. Analysis revealed that an initial GT thicker than 1.2 +/- 0.3 mm was associated with complete root coverage at the 6-month follow-up (P < 0.05). CONCLUSIONS: CAF is a predictable procedure to treat Miller's Class I mucogingival defects. Initial GT was the most significant factor associated with complete root coverage.

Adult↗

PubMed2005

The effect of platelet-rich plasma on the coronally advanced flap root coverage procedure: a pilot human trial.

BACKGROUND: Coronally advanced flap (CAF) has been shown to effectively treat gingival recession. Platelet-rich plasma (PRP), containing autologous growth factors, has been shown to promote soft tissue healing. Therefore, the purpose of this study was to evaluate the effects of PRP in combination with CAF. METHODS: Twenty-four systemically healthy patients participated in this study. A single Miller's Class I buccal recession defect per patient was treated. These patients were randomly assigned into CAF or PRP + CAF groups. Clinical parameters included recession depth (RD), recession width (RW), gingival thickness (GT), width of keratinized tissue (WKT), clinical attachment level (CAL), probing depth (PD), plaque index (PI), wound healing index (WHI), and gingival index (GI). PRP was prepared from whole blood drawn prior to surgery and applied to root surfaces. Patients were followed at 2, 4, 12, and 24 weeks post-surgery. RESULTS: Twenty-three patients completed the study. The RD at 24 weeks was significantly reduced from 2.9 +/- 0.5 to 0.5 +/- 0.6 mm in the CAF group (P < 0.05) and from 2.8 +/- 0.2 to 0.5 +/- 0.7 mm in the PRP + CAF group (P < 0.05). The mean root coverage was 83.5% +/- 21.8% in the CAF group and 81.0% +/- 28.7% in the CAF + PRP group (P > 0.05). Fourteen out of 23 patients (60.9%) experienced 100% root coverage at the 24-week postoperative follow-up. CONCLUSION: Based on the results of this pilot study, the application of PRP in CAF root coverage procedure provides no clinically measurable enhancements on the final therapeutic outcomes of CAF in Miller's Class I recession defects.

Adult↗

PubMed2005

Acellular dermal matrix for mucogingival surgery: a meta-analysis.

BACKGROUND: Many clinical studies revealed the effectiveness of acellular dermal matrix (ADM) in the treatment of mucogingival defects. The purpose of this meta-analysis was to compare the efficacy of ADM-based root coverage (RC) and ADM-based increase in keratinized tissues to other commonly used mucogingival surgeries. METHODS: Meta-analysis was limited to randomized clinical trials (RCT). Articles from January 1, 1990 to October 2004 related to ADM were searched utilizing the MEDLINE database from the National Library of Medicine, the Cochrane Oral Health Group Specialized Trials Registry, and through hand searches of reviews and recent journals. Relevant studies were identified, ranked independently, and mean data from each were weighted accordingly. Selected outcomes were analyzed using a meta-analysis software program. The significant estimates of the treatment effects from different trials were assessed by means of Cochrane's test of heterogeneity. RESULTS: 1) Few RCT studies were found to compile the data. In summary, selection identified eight RCT that met the inclusion criteria. There were four studies comparing ADM versus a connective tissue graft for root coverage procedures, two studies comparing ADM versus coronally advanced flap (CAF) for root coverage procedures, and two studies comparing ADM to free gingival graft in augmentation of keratinized tissue. 2) There were no statistically significant differences between groups for any of the outcomes measured (recession coverage, keratinized tissue formation, probing depths, and clinical attachment levels). 3) The majority of the analyses demonstrated moderate to high levels of heterogeneity. 4) Considering the heterogeneity values found among the studies, certain trends could be found: a) three out of four studies favored the ADM-RC group for recession coverage; b) a connective tissue graft tended to increase keratinized tissue compared to ADM (0.52-mm difference; P = 0.11); c) there were trends of increased clinical attachment gains comparing ADM to CAF procedures (0.56-mm difference; P = 0.16). CONCLUSIONS: Differences in study design and lack of data precluded an adequate and complete pooling of data for a more comprehensive analysis. Therefore, considering the trends presented in this study, there is a need for further randomized clinical studies of ADM procedures in comparison to common mucogingival surgical procedures to confirm our findings. It is difficult to draw anything other than tentative conclusions from this meta-analysis of ADM for mucogingival surgery, primarily because of the weakness in the design and reporting of existing trials.

Biocompatible Materials↗