• Journal of Periodontal and Implant Science
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• v.50 no.3
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• pp.197-206
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• 2020

Purpose: The aim of this study was to determine the impact of different compressive forces on deproteinized bovine bone mineral (DBBM) particles covered by native bilayer collagen membrane (NBCM) during alveolar ridge preservation (ARP) in the molar area, and to identify any histomorphometric and clinical differences according to the compressive force applied. Methods: Sockets were filled with DBBM after tooth extraction, and different compressive forces (30 N and 5 N, respectively) were applied to the graft material in the test (30 N) and control (5 N) groups. The DBBM in both groups was covered with NBCM in a double-layered fashion. A crossed horizontal mattress suture (hidden X) was then made. A core biopsy was performed using a trephine bur without flap elevation at the implant placement site for histomorphometric evaluations after 4 months. The change of the marginal bone level was measured using radiography. Results: Twelve patients completed the study. The histomorphometric analysis demonstrated that the mean ratios of the areas of new bone, residual graft material, and soft tissue and the implant stability quotient did not differ significantly between the groups (P>0.05). However, the mean size of the residual graft material showed a significant intergroup difference (P<0.05). Conclusions: The application of 2 compressive forces (5 N, 30 N) on particulate DBBM grafts during open-healing ARP in the posterior area led to comparable new bone formation, implant feasibility and peri-implant bone level.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.4
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• pp.386-390
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• 2007

This is about the case of loss of multiple teeth and alveolar bone caused by trauma, which needed alveolar bone augmentation before implant treatment. Alveolar bone was reconstructed using iliac bone graft, and thereafter first implant surgery was followed by consolidation period of 3 months. Iliac bone resorption was observed at the time of implant placement. And that resorption was more in the horizontal dimension than in the vertical. We conclude that additional treatment planning(e.g. using alveolar distraction osteogenesis or tissue expander) should be considered besides bone graft for vertical alveolar bone augmentation. For both maxilla and mandible, prosthodontic treatment was carried out $4{\sim}5$ months after implant placement. To compensate alveolar bone deficiency, partial hybrid overdenture on maxilla and implant-supported fixed bridge on mandible were fabricated, and the total treatment was finished.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.38
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• pp.41.1-41.6
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• 2016

Background: The goal of this study was to retrospectively evaluate the prognosis of minimal invasive horizontal ridge augmentation (MIHRA) technique using small incision and subperiosteal tunneling technique. Methods: This study targeted 25 partially edentulous patients (10 males and 15 females, mean age $48.8{\pm19.7years$) who needed bone graft for installation of the implants due to alveolar bone deficiency. The patients took the radiographic exam, panoramic and periapical view at first visit, and had implant fixture installation surgery. All patients received immediate or delayed implant surgery with bone graft using U-shaped incision and tunneling technique. After an average of 2.8 months, the prosthesis was connected and functioned. The clinical prognosis was recorded by observation of the peri-implant tissue at every visit. A year after restoration, the crestal bone loss around the implant was measured by taking the follow-up radiographs. One patient took 3D-CT before bone graft, after bone graft, and 2 years after restoration to compare and analyze change of alveolar bone width. Results: This study included 25 patients and 39 implants. Thirty eight implants (97.4 %) survived. As for postoperative complications, five patients showed minor infection symptoms, like swelling and tenderness after bone graft. The other one had buccal fenestration, and secondary bone graft was done by the same technique. No complications related with bone graft were found except in these patients. The mean crestal bone loss around the implants was 0.03 mm 1 year after restoration, and this was an adequate clinical prognosis. A patient took 3D-CT after bone graft, and the width of alveolar bone increased 4.32 mm added to 4.6 mm of former alveolar bone width. Two years after bone graft, the width of alveolar bone was 8.13 mm, and this suggested that the resorption rate of bone graft material was 18.29 % during 2 years. Conclusions: The bone graft material retained within a pouch formed using U-shaped incision and tunneling technique resulted with a few complications, and the prognosis of the implants placed above the alveolar bone was adequate.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.33.1-33.7
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• 2019

Background: The concept of the ideal morphology for the alveolar bone form is an important element to reconstruct or restore the in maximizing esthetic profile and functional alveolar bone restoration. The purpose of this preliminary study is to evaluate the normal alveolar bone structure to provide the standard reference and guide template for use in diagnosing for implant placement, determining the correct amount of bone augmentation in actual clinical practice and producing prostheses based on three-dimensional imaging assessment of alveolar bone. Methods: This study was included 11 men and 11 women (average age, 22.6 and 24.5 years, respectively) selected from among 127 patients. The horizontal widths of alveolar bone of maxilla and mandible were measured at the crestal, mid-root, and root apex level on MDCT (multi-detector computed tomography) images reconstructed by medical imaging software. In addition, tooth dimensions of the central incisors, canines, second premolars, and first molars of maxilla and mandible, including the horizontal width of the interdental alveolar bone crest, were also measured and statistically analyzed. Results: The horizontal alveolar bone width of the palatal side of maxilla showed a distinct increment from the alveolar bone crest to the apical region in both anterior and posterior areas. The average widths of the maxillary alveolar ridge were as follows: central incisor, 7.43 mm; canine, 8.91 mm; second premolar, 9.57 mm; and first molar, 12.38 mm. The average widths of the mandibular alveolar ridge were as follows: central incisor, 6.21 mm; canine, 8.55 mm; second premolar, 8.45 mm; and first molar, 10.02 mm. In the buccal side, the alveolar bone width was not increased from the crest to the apical region. The horizontal alveolar bone width of an apical and mandibular border region was thinner than at the mid-root level. Conclusions: The results of the preliminary study are useful as a clinical guideline when determining dental implant diameter and position. And also, these measurements can also be useful during the production of prefabricated membranes and customized alveolar bone scaffolds.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.2
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• pp.184-191
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• 2014

In the mandibular posterior molar area, ridge deficiency is an unfortunate obstacle in the field of implant dentistry. Many techniques are available to rebuild the deficient ridge. Selection and necessity of these techniques are associated with significant morbidity and often require a second surgical site. With the advent of guided bone regeneration (GBR), one may now graft the deficient ridge with decreased morbidity and without a second surgical site. In this case, guided bone regeneration procedures were performed with a combination of allograft, xenograft, and alloplast, excepting autogerous bone at severe defected mandibular alveolar ridge and then placed to the implant successfully. We report that implant placement were good in two cases.

• Journal of Periodontal and Implant Science
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• v.47 no.6
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• pp.372-380
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• 2017

Purpose: The aim of this prospective pilot study was to compare alveolar ridge preservation (ARP) procedures with open-healing approach using a single-layer and a double-layer coverage with collagen membranes using radiographic and clinical analyses. Methods: Eleven molars from 9 healthy patients requiring extraction of the maxillary or mandibular posterior teeth were included and allocated into 2 groups. After tooth extraction, deproteinized bovine bone mineral mixed with 10% collagen was grafted into the socket and covered either with a double-layer of resorbable non-cross-linked collagen membranes (DL group, n=6) or with a single-layer (SL group, n=5). Primary closure was not obtained. Cone-beam computed tomography images were taken immediately after the ARP procedure and after a healing period of 4 months before implant placement. Radiographic measurements were made of the width and height changes of the alveolar ridge. Results: All sites healed without any complications, and dental implants were placed at all operated sites with acceptable initial stability. The measurements showed that the reductions in width at the level 1 mm apical from the alveolar crest (including the bone graft) were $-1.7{\pm}0.5mm$ in the SL group and $-1.8{\pm}0.4mm$ in the DL group, and the horizontal changes in the other areas were also similar in the DL and SL groups. The reductions in height were also comparable between groups. Conclusions: Within the limitations of this study, single-layer and double-layer coverage with collagen membranes after ARP failed to show substantial differences in the preservation of horizontal or vertical dimensions or in clinical healing. Thus, both approaches seem to be suitable for open-healing ridge preservation procedures.

• Journal of Periodontal and Implant Science
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• v.50 no.1
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• pp.28-37
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• 2020

Purpose: The aim of our study was to determine the prevalence and degree of lingual concavities in the first molar region of the mandible to reduce the risk of perforating the lingual cortical bone during dental implant insertion. Methods: A total of 163 suitable cross-sectional cone-beam computed tomography images of edentulous mandibular first molar regions were evaluated. The mandibular morphology was classified as a U-configuration (undercut), a P-configuration (parallel), or a C-configuration (convex), depending on the shape of the alveolar ridge. The characteristics of lingual concavities, including their depth, angle, vertical location, and additional parameters, were measured. Results: Lingual undercuts had a prevalence of 32.5% in the first molar region. The mean concavity angle was 63.34°±8.26°, and the mean linear concavity depth (LCD) was 3.03±0.99 mm. The mean vertical distances of point P from the alveolar crest (Vc) and from the inferior mandibular border were 9.39±3.39 and 16.25±2.44, respectively. Men displayed a larger vertical height from the alveolar crest to 2 mm coronal to the inferior alveolar nerve (Vcb) and a wider LCD than women (P<0.05). Negative correlations were found between age and buccolingual width at 2 mm apical to the alveolar crest, between age and Vcb, between age and Vc, and between age and LCD (P<0.05). Conclusions: The prevalence of lingual concavities was 32.5% in this study. Age and gender had statistically significant effects on the lingual morphology. The risk of lingual perforation was higher in young men than in the other groups analyzed.

• Journal of Periodontal and Implant Science
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• v.39 no.3
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• pp.367-373
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• 2009

Purpose: Following tooth extraction caused by severe periodontitis, alveolar ridge dimension lose their original volume. To reduce the alveolar ridge dimension, the ridge preservation technique has been introduced and tested in many clinical studies with membrane alone or membrane plus graft, achieving reduced ridge loss compared to extraction only. The aim of the present clinical study was to compare the post-extraction dimensional changes in the membrane exposure group to non-exposure group during healing period following ridge preservation technique. Methods: Ridge preservation was performed in 44 extraction sites. After extraction, deproteinized bovine bone mineral coated with synthetic oligopeptide (Ossgen-$X15^{(R)}$) or deproteinized bovine bone mineral (Bio-$Oss^{(R)}$) was implanted into the socket. A collagen membrane (Bio-$Gide^{(R)}$) was trimmed to cover the socket completely and applied to the entrance of the socket. Four clinical parameters were compared between baseline and 6 months. Results: During healing period, membrane exposure was observed at 19 sites. At the re-entry, hard newly formed tissue were observed at the ridge preservation site. The grafted socket sites were well preserved in their volume dimension. In both groups, horizontal ridge width was reduced and vertical height was increased. There were not statistically significant differences in horizontal (-1.32 mm vs -1.00 mm) and vertical ridge change (2.24 mm vs 2.37 mm at buccal crest, 1.36 mm vs. 1.53 mm at lingual crest) between two groups. Conclusions: The ridge preservation approach after tooth extraction effectively prevented resorption of hard tissue ridge in spite of membrane exposure during healing period.

• Speech Sciences
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• v.8 no.2
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• pp.93-106
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• 2001

The pronunciation of English l and r was a consistent problem in learning English in Korea as well as Japan. This problem occurs from the fact that in Korea and Japan there is only one liquid sound. Substituting the Korean liquid for English l and r was a common error. The pronunciation of the dark l causes a further problem in pronouncing the English l sound. To see the relationship between the English l, r, and the Korean liquid sound, an electropalatographic (EPG) experiment was done. The findings were (1) there were no tongue contacts either on the alveolar ridge or on the palate during the articulation of the dark l. (2) The Korean liquid sound was different in the tongue contact points either from English l or r. The English clear l consistently touched the alveolar ridge in the forty tokens, but the Korean liquid sound in the intervocalic and word-final position touched mainly the alveopalatal area. The English r touched exclusively the velum area. The Korean intervocalic /l/ was similar to English flap in EPG and spectrographic data. There was evidence that the word-final Korean /l/ is a lateral.

• The Journal of the Korean dental association
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• v.19 no.12 s.151
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• pp.1045-1050
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• 1981

The 25-year old unmarried female patient has lost her mandibular molars bilaterally and her alveolar ridge has been atrophied for long term teeth missing. As rejected the removable partial denture, she was practiced the vitallium subperiosteal implants pertinent to atrophied alveolar ridge. Now, the results are satisfiable to both of the author and the patient. But it is necessary to observe the prognosis for some years.