Feasibility of Assessing Maxillary and Mandibular Bone Mineral Density for Dental Implantation by Using Multidetector Computed Tomography.

PURPOSE: The purpose of this study was to evaluate the feasibility of measuring bone mineral density (BMD) of the maxillary and mandibular bones for dental implantation by using multidetector computed tomography (MDCT). MATERIALS AND METHODS: We performed MDCT in 141 patients (78 women and 63 men) at the lumbar vertebrae and at the maxillary and mandibular bones, with a view to dental implantation, from July 2015 to June 2017. Quantitative CT (QCT) using MDCT was performed to obtain Hounsfield unit (HU) values for the maxillary and mandibular bones and to obtain T scores for the lumbar vertebrae. We statistically analyzed the relationships among HU values, and the correlations of QCT values with T scores and of T scores with HU values. RESULTS: There were statistically significant correlations among all these parameters. CONCLUSIONS: QCT using MDCT of the maxillary and mandibular bones seems to be a feasible method for measuring BMD before dental implantation.

Comparative Study on Osseointegration of Implants After Flap and Flapless Surgery in the Mandible of Dogs.

PURPOSE: The objective of this study was to compare the implant stability and osseointegration of implants using a flap or flapless technique. MATERIAL AND METHODS: Mandibular premolars and molars were extracted from both sides in 6 dogs. After 8 weeks, 4 fixtures were implanted using either a flap or flapless technique. Implant stability quotient was measured on insertion and at 2, 4, and 8 weeks later. The animals were killed while the tissues were histologically analyzed. RESULTS: Implant stability increased for 8 weeks, and no statistically significant differences were observed between the surgical protocols. Bone-implant contact showed 60.27% ± 30.99% for flapless surgery and 59.73% ± 17.12% for flap surgery. And the results of new bone formation area from total area showed 56.07% ± 27.78% for flapless surgery and 57.00% ± 14.66% for flap surgery. There were no statistically significant differences. CONCLUSION: This study showed no significant difference in implant stability as well as osseointegration regardless of flap or flapless technique.

Incidence and Management of Fractured Dental Implants: Case Reports.

The fracture of dental implants is a rare occurrence in clinical settings. Possible causes of implant fracture include design or production flaws, overloaded occlusion force, implant location, metal fatigue, and bone resorption around the implant. This study reports on the successful removal and reimplantation of fractured implants.

Histomorphometric Analysis of Contaminated Autogenous Tooth Graft Materials After Various Sterilization.

PURPOSE: The purpose of this study was to evaluate histomorphometrically contaminated autogenous tooth graft materials, which were resterilized. MATERIALS AND METHODS: The intentional defects (diameter: 8 mm, depth: 4 mm) were formed around implant fixture on the iliac crest of 6 mongrel dogs. Autogenous tooth graft materials were made by extracted premolars. After the contamination of the tooth materials, graft procedure was performed; no contaminated group (control group), contaminated groups (nonsterilization group [group 1], ethylene oxide [EO] gas group [group 2], and autoclave group [group 3]). The bone-to-implant contact (BIC) and the new bone formation rate (NBFR) were evaluated after sacrifice. RESULTS: The BIC and NBFR of groups 1 and 3 were significantly lower than the control group after 4 weeks. The BIC and NBRF of group 3 were significantly lower than the control group after 8 weeks. However, the BIC and NBRF of group 2 was not significantly different comparing with the control group after 4 and 8 weeks. CONCLUSION: Sterilization using EO gas may be more favorable than high-pressure sterilization in cases the reuse of contaminated autogenous tooth graft materials.

Implant Stability Measurements in the Long-Term Follow-up of Dentis Implants: A Retrospective Study With Periotest.

PURPOSE: The purpose of this study was to evaluate retrospectively the stability of Dentis implant with the Periotest. METHODS: In total, 36 patients and 88 implants were investigated. Periotest was used to measure implant stability, and a periapical view was taken immediately after surgery and again immediately after, 3 months after, 6 months and 5 years after prosthesis placement. Bone loss on the periapical view, bone quality according to tactile sensation, and area of implant installation were assessed. RESULTS: The mean Periotest value (PTV) immediately after surgery was -1.02, and the mean bone loss rate (bone loss/fixture length × 100) at 6 months after prosthesis placement was 8.42%. PTV was higher with more bone loss (types III, IV vs types I, II bone). The lowest mean PTV was in the lower molar area (-1.48), followed by the lower anterior (-1.41), upper molar (0.11), and upper anterior area (5). One implant failed and survival rates were 98.9%. CONCLUSION: Implant stability was lower in cases with more bone loss and poor bone quality and in the maxilla versus the mandible.

Evaluation of bone formation after grafting with deproteinized bovine bone and mineralized allogenic bone.

PURPOSE: The purpose of this study was to evaluate the ability of new bone formation of deproteinized bovine bone (Bio-Oss) and mineralized allogenic bone (Tutoplast). MATERIALS AND METHODS: Sixty rats were divided into control and experimental groups (groups 1 and 2): control group, unfilled control; group 1, Bio-Oss; group 2, Tutoplast, respectively. The animals were killed after 6 and 12 weeks, and newly formed bone was analyzed histomorphometrically. RESULTS: In the control group, some new bone formed in the rim of the defect area. In the group 1, newly formed bone was thinner than the adjacent normal bone, and Bio-Oss particles were observed. In the group 2, showed a pattern of gradual fusion with adjacent bone, as well as particles in some areas, similar to the Bio-Oss-treated group. In the 12-week groups, the amount of new bone formation was significantly higher in the experimental groups than in the control group, and it was significantly higher in group 2 than in group 1. CONCLUSION: Although Tutoplast and Bio-Oss graft materials seem to be useful for bone grafts, Tutoplast showed more active new bone formation than Bio-Oss.

Displaced implants into maxillary sinus: report of cases.

Although the number of implant placement in the edentulous maxillary region is increasing, there are often some cases in which implants accidentally get displaced into maxillary sinus because of low bone quality, insufficient bone height, bone resorption after surgery, and improper treatment plan. Implants displaced into the maxillary sinus can cause some complications, including mucosal thickening and sinusitis; however, there are also many cases causing no symptoms at all. Treatment procedures for implants displaced into maxillary sinus are observation, removal of implants through intraoral approach, and removal through nasal cavity using endoscope. But treatment may vary according to the presence of sinusitis, ostium obstruction, and oroantral fistula. In this study, 4 patients with present illness of implants displaced into maxillary sinus were selected, and appropriate evaluation and treatment for these cases were studied.

Osteogenic ability according to the decalcified modality of auto-tooth bone grafts in peri-implant defects in dogs.

PURPOSE: The purpose of this study was to evaluate the bone generation capacity of the autotransplantation material with clinical and histological analyses after controlled acid treatment conditions. MATERIAL AND METHODS: Bony defects were formed in the femur. Then, autotransplantation material was grafted after hydroxyapatite-coated implant placement. Experimental groups were classified according to the acid treatment method: 2% H2SO4 (group 1), 2% HCl (group 2), 2% HNO3 (group 3), or 2% ethylenediaminetetraacetic acid (EDTA) (group 4). RESULTS: The new bone formation area and bone-implant contact (BIC) of the autotransplantation materials were measured after 8 weeks. The new bone formation area in experimental groups 2, 3, and 4 were greater than that in the control group (no graft) and in experimental group 1 at 8 weeks, and the BIC of experimental group 4 was greater than that in the control group and in experimental group 1; these differences showed statistical significance (P < 0.05). CONCLUSION: Auto-tooth bone treated with EDTA resulted in more effective bone formation in dogs' femurs than bone treated with other solutions.

Enhanced attachment of human osteoblasts on NH3-treated poly(L-lactic acid) membranes for guided bone regeneration.

Barrier membranes for guided bone regeneration (GBR) were prepared by a solvent casting method using solutions of poly(L-lactic acid) (PLLA) and chitosan. PLLA and PLLA/chitosan membranes were treated with ammonia gas plasma. PLLA/chitosan membranes were successfully fabricated, and the surface of the PLLA/chitosan membrane was clearly modified by NH3 plasma treatment according to attenuated total reflectance (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) analyses. Additionally, water contact angle testing indicated that the hydrophilicity of these membranes was significantly increased. MG-63 cells were cultured on each type of membrane, and cell viability was examined using an MTT assay. After one week of culturing, MG-63 cells were more abundant on PLLA/chitosan membranes than on PLLA membranes. The cell viability of PLLA/chitosan membranes with plasma treatment was significantly higher than that of PLLA membranes. These results suggest that this plasma-treated membrane is suitable for GBR and is a promising source of bioactive membrane material for bone regeneration.

Consideration of various bone quality evaluation methods.

PURPOSE: Bone quality at the implant site has a significant effect on the success and prognosis of implants. The purpose of this article was to evaluate several methods used in evaluating bone quality and discuss the advantages and disadvantages. METHODS: The search was made using PubMed database about quantitative computed tomography (QCT), and quantitative cone-beam computerized tomography (QCBCT), dual energy x-ray absorptiometry (DXA) scans, the resistance force against the hands of the surgeon, assessment of the effect of the torque of the drill, the initial fixed value of the implant, and fractal analysis according to the Lekholm and Zarb, and Misch classifications as the standard. RESULTS: The method for measuring the resistance force and torque during implant placement and the method used to determine the implant's initial implant fixed value were easy and simple. QCBCT was reported to involve less radiation and to be more objective than QCT. DXA and fractal analysis have limits when used to classify bone quality as type II or type III. CONCLUSION: Among the methods used to evaluate bone quality in implants, a method using computed tomography, measured in Hounsfield units, was found to be the most predictive.

Histomorphometric analysis of bone formation in bony defects around implants in adult dogs: a comparison of grafts of low and high heat-treated autogenous tooth ash.

PURPOSE: The purpose of this study was to compare the bone formation of autogenous tooth ash treated with different temperatures. MATERIALS AND METHODS: Heat treatment was rendered by powder after extraction of teeth from dogs. The bony defects were made at iliac and resorbable blast medium surfaced implant placement and bone graft was performed; no bone graft group (control group), low heat-treated tooth ash group (group 1), high heat-treated tooth ash group (group 2). Right side had healing periods of 12 weeks, and the left side had 6 weeks. Histomorphometrical analysis was performed at 12 weeks. RESULTS: The control group had poor bone formation and showed large loose connective tissue. Group 1 displayed good healing and bone formation. Group 2 showed higher rate of bone formation than group 1 and the control group. The high heat-treated tooth ash group showed a statistically significant increase in the rate of bone formation in the early stage. CONCLUSION: The heat-treated autogenous tooth ash powder showed excellent new bone formation. The temperature of heat treatment is an important factor in new bone formation. The high heat treatment was the optimal treatment method for making tooth ash than the low heat treatment.

Development and structure of a novel barrier membrane composed of drug-loaded poly(lactic-co-glycolic acid) particles for guided bone regeneration.

A novel barrier membrane composed of poly(lactic-co-glycolic acid) particles loaded with dexamethasone (DEX) as a bioactive molecule was produced via a modified nanoprecipitation method without any mixing. The particle membranes had a bilayer structure: one side was smooth and had a compact surface that was connected to larger particles, while the opposite side was rough, porous and connected to smaller particles. Additionally, a cross-section of the particle membrane had a porous structure with nano and micro sized irregular pores. Process optimization revealed that NaCl concentration in the water phase, with acetone as solvent and water as a non-solvent, played critical roles in determining the properties of the particle membranes, such as DEX encapsulation efficiency, thickness and surface morphologies of the particle membranes. A novel barrier membrane containing DEX using polymer particle drug capture technology has been successfully developed.

A multicenter prospective study in type IV bone of a single type of implant.

PURPOSE: To analyze the success and survival rates of the Osstem GSII (Osstem, Busan, Korea) implant in type IV bone. MATERIALS: A prospective, multicenter (5 centers) study was conducted by examining the relationship between implant success and survival rates, and several patient and surgical parameters. The implants were placed in 82 patients who visited several nationwide dental hospitals and clinics between 2007 and 2008, followed by clinical and radiographic analyses. RESULTS: In type IV bone, the implant success and survival rates were 93.23% and 95.83%, respectively. The maxillary premolar and mandibular anterior tooth areas showed success rates of 100%. The most widely used implant diameter and length was 5.0 and 13 mm, respectively, but the diameter and length had no effect on success rates. However, success rates appeared to decrease with age. CONCLUSIONS: The results indicated that the Osstem GSII implant is highly effective in poor-quality type IV bone.

Clinical study of graft materials using autogenous teeth in maxillary sinus augmentation.

PURPOSE: The purpose of this study was to evaluate the effectiveness of autogenous tooth bone graft materials. MATERIALS AND METHODS: Hundred implants in 51 patients were selected, and the patients received maxillary sinus augmentation and implant placement using autogenous tooth graft materials at the Chosun University Dental Hospital and Seoul National University Bundang Hospital between July 2009 and November 2010. RESULTS: In cases using autogenous tooth bone graft alone, or together with other graft material, the implant survival rate was 96.15%. On histomorphologic examination, autogenous tooth bone graft materials showed gradual resorption and new bone formation through osteoconduction and osteoinduction. CONCLUSIONS: The results indicated that autogenous tooth bone graft materials are appropriate for use in maxillary sinus augmentation.

Efficacy of Pentax airway scope versus Macintosh laryngoscope when used by novice personnel: A prospective randomized controlled study.

Objective To determine whether intubation education using the Pentax Airway Scope (AWS) in normal airways is more useful than direct laryngoscopy (Macintosh laryngoscope) in novice personnel. Methods Eleven intern doctors without intubation experience performed 60 sequential intubations with each device on a manikin and 10 sequential intubations in adult patients. The time required for successful intubation, percentage of glottic opening (POGO) score, number of intubation attempts, and number of dental injuries were analyzed for each intubation technique. Results The mean (standard deviation) time required for successful intubation decreased as the number of intubations increased and was significantly shorter with the Pentax AWS than direct laryngoscope [22.6 (7.3) vs. 29.6 (10.0) and 33.0 (8.0) vs. 44.7 (5.6) s, respectively] in both the manikin and clinical studies. The Pentax AWS was also associated with higher POGO scores than the direct laryngoscope [81.7 (8.9) vs. 55.1 (13.2) and 80.9 (9.7) vs. 49.6 (16.5), respectively] and fewer intubation attempts. Fewer dental injuries occurred with the Pentax AWS in the manikin study. Conclusions Novices performed intubation more rapidly and easily with an improved laryngeal view using the Pentax AWS. We suggest that intubation education with video laryngoscopy should be mandatory along with direct laryngoscope training.

Comparative study on the osseointegration of implants in dog mandibles according to the implant surface treatment.

OBJECTIVES: This study compared the impact of implant surface treatment on the stability and osseointegration of implants in dog mandibles. MATERIALS AND METHODS: Six adult dogs received a total of 48 implants that were prepared using four different surface treatments; resorbable blast media (RBM), hydroxyapatite (HA), hydrothermal-treated HA, and sand blasting and acid etching (SLA). Implants were installed, and dogs were separated into 2- and 4-week groups. Implant stability was evaluated via Periotest M, Osstell Mentor, and removal torque analyzers. A histomorphometric analysis was also performed. RESULTS: The stability evaluation showed that all groups generally had satisfactory values. The histomorphometric evaluation via a light microscope revealed that the HA surface implant group had the highest ratio of new bone formation on the entire fixture. The hydrothermal-treated HA surface implant group showed a high ratio of bone-to-implant contact in the upper half of the implant area. CONCLUSION: The hydrothermal-treated HA implant improved the bone-to-implant contact ratio on the upper fixture, which increased the implant stability.

Autogenous teeth used for bone grafting: a comparison with traditional grafting materials.

OBJECTIVES: This study evaluated the surface structures and physicochemical characteristics of a novel autogenous tooth bone graft material currently in clinical use. STUDY DESIGN: The material's surface structure was compared with a variety of other bone graft materials via scanning electron microscope (SEM). The crystalline structure of the autogenous tooth bone graft material from the crown (AutoBT crown) and root (AutoBT root), xenograft (BioOss), alloplastic material (MBCP), allograft (ICB), and autogenous mandibular cortical bone were compared using x-ray diffraction (XRD) analysis. The solubility of each material was measured with the Ca/P dissolution test. RESULTS: The results of the SEM analysis showed that the pattern associated with AutoBT was similar to that from autogenous cortical bones. In the XRD analysis, AutoBT root and allograft showed a low crystalline structure similar to that of autogenous cortical bones. In the CaP dissolution test, the amount of calcium and phosphorus dissolution in AutoBT was significant from the beginning, while displaying a pattern similar to that of autogenous cortical bones. CONCLUSIONS: In conclusion, autogenous tooth bone graft materials can be considered to have physicochemical characteristics similar to those of autogenous bones.

Prognosis and evaluation of tooth damage caused by implant fixtures.

Damage to adjacent teeth is one of the various complications that may occur during implant placement and is often the result of improper direction during fixture placement or excessive depth of placement. In general, if detrimental symptoms, such as reaction to percussion in damaged teeth, mobility, and pulp necrosis, are not present, osseointegration should be observed at follow-up. In three cases, the possibility of root damage due to an implant fixture placed too close to each adjacent tooth was perceived on radiographs. However, in all of these cases, there were no clinical symptoms or radiographic changes present in the tooth, and the implants did not exhibit decreased stability or peri-implantitis. Therefore, we can carefully predict that the implant fixture close to the adjacent tooth did not invade the cementum of the root, and therefore did not produce the suspected pulpal damage or periradicular symptoms. In this study, we considered both the implant status as well as the adjacent tooth.

Restoration of strip crown with a resin-bonded composite cement in early childhood caries.

Background. Early childhood caries is a widely prevalent disease throughout the world. It is necessary to treat this condition in early childhood; however, child behavior management may be particularly challenging during treatment. To overcome this challenge, we used Carigel to remove caries and RelyX Unicem resin cement for strip crown restoration. It not only has the desired aesthetic effect but is also more effective for primary teeth, which are used for a shorter period than permanent teeth are. Case Presentation. We report a case of three pediatric patients with early childhood caries, in whom caries was removed by using Carigel to avoid the risk of pulpal exposure associated with high-speed handpieces. Subsequently, aesthetic restoration was performed using strip crown with RelyX Unicem self-adhesive resin cement. Conclusion. RelyX Unicem has the following advantages: (1) not requiring have any special skills for the dentist for performing the procedure, (2) decreased occurrence of bubbles during injection of the cement, and (3) overall short duration of the procedure. Thus, it is appropriate for the treatment of pediatric patients whose behavior is difficult to manage. However, further studies are required in order to establish the use of RelyX Unicem as a stable restorative material in early childhood caries.

A comparative study of bone formation following grafting with different ratios of particle dentin and tricalcium phosphate combinations.

This study aimed to evaluate the bone regeneration relative to tooth powder and tricalcium phosphate (TCP) mixing ratios using the rabbit cranium defect model. The tooth powder was mixed with TCP in 1:1, 3:1, and 1:3 ratios, and the different ratios were implanted in the rabbit cranium defect for 4 and 8 weeks. Powders crystal structure evaluated using scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and new bone formation (NBF) was analyzed using micro-computed tomography (CT) and histologic examination. NBF in the control group was restricted to the defect margins. More NBF was observed around the defect margins in the experimental groups compared with the control group. Specifically, active NBF was identified around the implant materials of the centrifugal part of the defect and defect margins in the 3:1 tooth powder: TCP group. Our results suggested that tooth powder and TCP may be useful in bone regeneration.