• Title/Summary/Keyword: Dental Implantation

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Influence of the implant abutment types and the dynamic loading on initial screw loosening

  • Kim, Eun-Sook;Shin, Soo-Yeon
    • The Journal of Advanced Prosthodontics
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    • v.5 no.1
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    • pp.21-28
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    • 2013
  • PURPOSE. This study examined the effects of the abutment types and dynamic loading on the stability of implant prostheses with three types of implant abutments prepared using different fabrication methods by measuring removal torque both before and after dynamic loading. MATERIALS AND METHODS. Three groups of abutments were produced using different types of fabrication methods; stock abutment, gold cast abutment, and CAD/CAM custom abutment. A customized jig was fabricated to apply the load at $30^{\circ}$ to the long axis. The implant fixtures were fixed to the jig, and connected to the abutments with a 30 Ncm tightening torque. A sine curved dynamic load was applied for $10^5$ cycles between 25 and 250 N at 14 Hz. Removal torque before loading and after loading were evaluated. The SPSS was used for statistical analysis of the results. A Kruskal-Wallis test was performed to compare screw loosening between the abutment systems. A Wilcoxon signed-rank test was performed to compare screw loosening between before and after loading in each group (${\alpha}$=0.05). RESULTS. Removal torque value before loading and after loading was the highest in stock abutment, which was then followed by gold cast abutment and CAD/CAM custom abutment, but there were no significant differences. CONCLUSION. The abutment types did not have a significant influence on short term screw loosening. On the other hand, after $10^5$ cycles dynamic loading, CAD/CAM custom abutment affected the initial screw loosening, but stock abutment and gold cast abutment did not.

Postulated release profile of recombinant human bone morphogenetic protein-2 (rhBMP-2) from demineralized dentin matrix

  • Um, In-Woong;Ku, Jeong-Kui;Lee, Bu Kyu;Yun, Pil-Young;Lee, Jeong Keun;Nam, Jeong-Hun
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.45 no.3
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    • pp.123-128
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    • 2019
  • Demineralized dentin matrix (DDM) has been used as a recombinant human bone morphogenetic protein-2 (rhBMP-2) carrier in many clinical trials. To optimize the clinical safety and efficacy of rhBMP-2 with DDM, efforts have been made to improve the delivery of rhBMP-2 by 1) lowering the administered dose, 2) localizing the protein, and 3) prolonging its retention time at the action site as well as the bone forming capacity of the carrier itself. The release profile of rhBMP-2 that is associated with endogenous BMP in dentin has been postulated according to the type of incorporation, which is attributed to the loosened interfibrillar space and nanoporous dentinal tubule pores. Physically adsorbed and modified, physically entrapped rhBMP-2 is sequentially released from the DDM surface during the early stage of implantation. As DDM degradation progresses, the loosened interfibrillar space and enlarged dentinal tubules release the entrapped rhBMP-2. Finally, the endogenous BMP in dentin is released with osteoclastic dentin resorption. According to the postulated release profile, DDM can therefore be used in a controlled manner as a sequential delivery scaffold for rhBMP-2, thus sustaining the rhBMP-2 concentration for a prolonged period due to localization. In addition, we attempted to determine how to lower the rhBMP-2 concentration to 0.2 mg/mL, which is lower than the approved 1.5 mg/mL.

Effect of cryotherapy duration on experimentally induced connective tissue inflammation in vivo

  • Jorge Vera;Mayra Alejandra Castro-Nunez;Maria Fernanda Troncoso-Cibrian;Ana Gabriela Carrillo-Varguez;Edgar Ramiro Mendez Sanchez;Viviana Sarmiento;Lourdes Lanzagorta-Rebollo;Prasanna Neelakantan;Monica Romero;Ana Arias
    • Restorative Dentistry and Endodontics
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    • v.48 no.3
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    • pp.29.1-29.8
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    • 2023
  • Objectives: This study tested the hypothesis that cryotherapy duration influences lipopolysaccharide (LPS)-induced inflammation in a rat model. Materials and Methods: Six Wistar rats (Rattus norvegicus albinus) were used. Five sites were selected per animal and divided into 5 groups: a negative control group (NC), 2 positive control groups (PC1 and PC2), and 2 experimental groups (E1 and E2). Cryotherapy was applied for 1 minute (E1) or 5 minutes (E2). An acute inflammatory response was induced in the PC and E groups via subcutaneous administration of 0.5 mL/kg. In the PC2 group, a catheter was inserted without additional treatment. For the E1 and E2 groups, 2.5℃ saline solution was administered through the implanted catheters for 1 and 5 minutes, respectively. The rats were sacrificed, and samples were obtained and processed for histological analysis, specifically examining the presence of polymorphonuclear neutrophils and hemorrhage. The χ2 test was used to compare the presence of acute inflammation across groups. Dependent variables were compared using the linear-by-linear association test. Results: Inflammation and hemorrhage varied significantly among the groups (p = 0.001). A significantly higher degree of acute inflammation was detected (p = 0.0002) in the PC and E1 samples than in the E2 group, in which cryotherapy was administered for 5 minutes. The PC and E1 groups also exhibited significantly greater numbers of neutrophils (p = 0.007), which were essentially absent in both the NC and E2 groups. Conclusions: Cryotherapy administration for 5 minutes reduced the acute inflammation associated with LPS and catheter implantation.

Interstitial Vaginal Needle Implantation in Gynecological Tumors : Design and Construction of Applicator (부인과암에서 조직내 삽입 방사선치료 - Applicator의 고안 및 제작-)

  • Kang, Seung-Hee;Chun, Mi-Son;Kang, Hae-Jin;Jung, Chil;Son, Jeong-Hyae
    • Radiation Oncology Journal
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    • v.16 no.2
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    • pp.167-175
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    • 1998
  • Purpose : It is not a simple task to achieve the ideal isodose curve with a standard vaginal applicator or sing1e plane needle impant in the paravaginal tissue when primary or recurrent gynecological neoplasms(cervical cancers, vaginal cancers and vulvar cancers) are treated as a boost following external beam radiotherapy. The authors introduce the development and construction of a simple, inexpensive, customized applicator for volume implant to maximize the radiation dose to the tumor while minimizing the dose to the rectum and the bladder. Materials and Methods : Nine patients underwent Ir-192 transperineal interstitial implantation for either recurrent(5 cases) or primary(3 cases) cervical cancers or primary vaginal cancer(1 case) between August 1994 and February 1998 at Ajou university hospital. First 3 cases were performed with a sing1e plane implant guided by digital palpation. Because of inadequate isodose coverage in the tumor volume in first 3 cases, we designed and constructed interstitial vaginal applicator for volume implant to improve tumor dose distribution and homogeneity while sparing the surrounding normal tissue. Our applicators consist of vaginal obturator and perineal template that made of the clear acrylamide and dental mold material$(Provil^{(R)})$. The applicators were customized individually according to the tumor size and its location Both HDR and LDR irradiation were given with these applicators accomodating 6 Fr needles(Microselectron Nucletron). The pretreatment planning prior to actual implant was performed whenever possible. Results : Needles can be inserted easily and evenly into the tumor volume through the holes of templates, requiring less efforts and time for the implant procedure. Our applicators made of materials available from commercial vendors. These have an advantage that require easy procedure, and spend relatively short time to construct. Also it was possible to fabricate applicators to individualize according to the tumor size and its location and to achieve the ideal isodose coverage. We found an accurate needle arrangement and ideal dose distribution through the CT scan that was obtained in 3 cases after needle implant. Three patients with primary cervical and vaginal cancers were controlled locally at final follow up. But all recurrent cases failed to do so. Conclusion : The authors introduce inexpensive, simple interstitial vaginal templates which were self-designed and constructed using materials available from commercial vendors such as acrylanide and dental mold material $(Provil^{(R)})$.

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C-shaped root canal system in mandibular 2nd molars in Korean people evaluated by cone beam computed tomography (Cone beam computed tomography를 이용하여 한국인 제2하악 대구치에서 C형 근관계에 대한 평가)

  • Kim, Miyeon;Kim, Jeonghee;Kim, Sunho;Song, Byungchul;Nam, Wook
    • Journal of Dental Rehabilitation and Applied Science
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    • v.32 no.1
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    • pp.32-37
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    • 2016
  • Purpose: To determine the anatomical characteristic of C-shaped canal systems in Korean mandibular 2nd molars by cone beam computed tomography (CBCT). Materials and Methods: The 824 CBCT images were evaluated. These patients were taken CBCT for the diagnosis and treatment of dental implantation on 2013. The 711 mandibular 2nd molars were examined. The configuration of root canal systems were classified according to modified Melton's classifications. Results: Of the 711 mandibular 2nd molars, 21.5% had C-shaped canal systems. This prevalence did not differ with tooth position. Most of the C-shaped canals with bilateral molars were symmetrical. Of the C-shaped canal, the most common configuration Type were Melton's Type I (89%) in the orifice level and Melton's III (83.8%) in the apical level. The prevalence of C-shaped canal was higher in female (25%) than male (13.9%) (P < 0.05). Conclusion: A high prevalence of C-shaped canals were observed in Korean mandibular 2nd molars. For successful C-shaped root canal treatment, the comprehension of root canal systems was important.

AN EXPERIMENTAL STUDY AND CASE ANALYSIS OF ACELLULAR DERMAL MATRIX IMPLANTATION FOR RESTORATION OF SOFT TISSUE DEFECTS (연조직 결손부 회복을 위한 무세포성 진피 기질 이식에 대한 실험연구 및 증례분석)

  • Ryu, Sun-Youl;Ryu, Jae-Young
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.30 no.1
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    • pp.1-10
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    • 2008
  • Purpose: This study was aimed to examine the resorption rate, the healing pattern, and the response of the surrounding tissue after the graft of the acellular dermal matrix ($AlloDerm^{(R)}$) and the autogenous dermis, and to report the clinical result of the use of $AlloDerm^{(R)}$ in order to restore the soft tissue defects. Methods: Twenty mature rabbits, weighing about 3 ㎏, were used for the experimental study. The $10\times10$ mm-size autogenous dermis and the $AlloDerm^{(R)}$ were grafted to the space between the external abdominal oblique muscle and the fascia of the rabbits. And the $AlloDerm^{(R)}$ was grafted to the pocket between the skin and the underlying perichondrium of rabbit ear. The resorption rate of the grafted sites was calculated, and the tissue specimens were histologically examined at 1, 2, 4, and 8 weeks after the graft. The five patients with the cleft-lip nasal deformity and the one patient with the saddle nose deformity, who received the $AlloDerm^{(R)}$ graft to restore the facial soft tissue defects, were reviewed for the clinical study. Results: The resorption rate at 8 weeks after the graft was 21.5% for the autogenous dermis, and 16.0% $AlloDerm^{(R)}$. In microscopic examinations, the infiltration of the inflammatory cells and the epidermal inclusion cyst were observed in the autogenous dermis graft. However, the neovascularization and the progressive growth of the new fibroblasts were shown in the $AlloDerm^{(R)}$ graft. And the six patients, who received the $AlloDerm^{(R)}$ graft, demonstrated the good stability of the grafts and improved appearance. There were no remarkable complications such as inflammation, rejection, dislocation, and severe absorption in the clinical cases. Conclusion: These results suggest that $AlloDerm^{(R)}$ can be an useful graft material for restoration of soft tissue defects because of the good stability and the tissue response without the remarkable clinical complications.

HISTOLOGICAL AND CLINICAL STUDY OF ARTIFICIAL DERMIS IMPLANTATION FOR RESTORATION OF SOFT TISSUE DEFECTS (연조직 결손부 회복을 위한 인공진피 이식의 조직학적 및 임상적 연구)

  • Ryu, Sun-Youl;Kim, Sun-Kook
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.32 no.5
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    • pp.410-417
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    • 2006
  • The present study was aimed to compare the resorption rate and the histological change of the autogenous dermis and the artificial dermis (Terudermis$^{(R)}$) after the transplantation, and to report the clinical results of the use of Terudermis$^{(R)}$ in order to restore the soft tissue defect. Twenty mature rabbits, weighing about 2 kg, were used for the experimental study. The autogenous dermis and the Terudermis$^{(R)}$ size 1${\times}$1 cm were transplanted to the space between the external abdominal oblique muscle and the external abdominal oblique fascia of the each rabbits. They were divided into 4 groups (n=5 each) and gathered at 1, 2, 4, and 8 weeks after the transplantation. The resorption rate was calculated, and H-E stain was preformed to observe the histological changes. The chart review of the 17 patients who received Terudermis$^{(R)}$ graft to the facial soft tissue defects was conducted for the clinical study. The resorption rate at 8 weeks after the transplantation was 21.5% for the autogenous dermis, and 36.4% Terudermis$^{(R)}$. In microscopic examinations, the infiltration of the inflammatory cells and the epidermal inclusion cyst were observed in the autogenous dermis graft. The neovascularization and the progressive growth of the new fibroblast were shown in the Terudermis$^{(R)}$ graft. In clinical data of 17 patients, the size of the grafted Terudermis$^{(R)}$ was from 1.5$cm^2$ to 7.5$cm^2$ (average 3.5$cm^2$). Follow-up ranged from 5 to 25 months. Fourteen patients with cleft palate demonstrated stability of the graft and unremarkable complications. But unstability of the graft and the partial relapse were observed in three patients received the vestibuloplasty. These results indicate that Terudermis$^{(R)}$ can be available substitute of autogenous dermis because of the stability about resorption, the histocompatibility, and the unremarkable clinical complications.

Effect of bFGF and fibroblasts combined with hyaluronic acid-based hydrogels on soft tissue augmentation: an experimental study in rats

  • Lee, Su Yeon;Park, Yongdoo;Hwang, Soon Jung
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.41
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    • pp.47.1-47.10
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    • 2019
  • Background: Hyaluronic acid (HA) has been applied as a primary biomaterial for temporary soft tissue augmentation and as a carrier for cells and the delivery of growth factors to promote tissue regeneration. Although HA derivatives are the most versatile soft tissue fillers on the market, they are resorbed early, within 3 to 12 months. To overcome their short duration, they can be combined with cells or growth factors. The purpose of this study was to investigate the stimulating effects of human fibroblasts and basic fibroblast growth factors (bFGF) on collagen synthesis during soft tissue augmentation by HA hydrogels and to compare these with the effects of a commercial HA derivative (Restylane®). Methods: The hydrogel group included four conditions. The first condition consisted of hydrogel (H) alone as a negative control, and the other three conditions were bFGF-containing hydrogel (HB), human fibroblast-containing hydrogel (HF), and human fibroblast/bFGF-containing hydrogel (HBF). In the Restylane® group (HGF), the hydrogel was replaced with Restylane® (R, RB, RF, RBF). The gels were implanted subdermally into the back of each nude mouse at four separate sites. Twelve nude mice were used for the hydrogel (n = 6) and Restylane® groups (n = 6). The specimens were harvested 8 weeks after implantation and assessed histomorphometrically, and collagen synthesis was evaluated by RT-PCR. Results: The hydrogel group showed good biocompatibility with the surrounding tissues and stimulated the formation of a fibrous matrix. HBF and HF showed significantly higher soft tissue synthesis compared to H (p < 0.05), and human collagen type I was well expressed in HB, HF, and HBF; HBF showed the strongest expression. The Restylane® filler was surrounded by a fibrous capsule without any soft tissue infiltration from the neighboring tissue, and collagen synthesis within the Restylane® filler could not be observed, even though no inflammatory reactions were observed. Conclusion: This study revealed that HA-based hydrogel alone or hydrogel combined with fibroblasts and/or bFGF can be effectively used for soft tissue augmentation.

Implant placement simultaneously sinus augmentation using crestal approach in severely atrophic maxilla; minimally invasive approach (골 흡수가 심한 상악 구치부에서 치조정 접근법을 이용하여 상악동 골이식술 동시 임플란트 식립)

  • Kim, Hyun-Joo;Kwon, Eun-Young;Choi, Jeomil;Lee, Ju-Youn;Joo, Ji-Young
    • Journal of Dental Rehabilitation and Applied Science
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    • v.33 no.1
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    • pp.47-54
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    • 2017
  • The atrophy of edentulous ridge and pneumatization of the maxillary sinus often limit the volume of bone available for implant placement on maxillary posterior teeth. Most clinicians suffer difficulties from poor bone quality and quantity on maxillary posterior site. Thus, the success of maxillary posterior implant surgery depends on the increase of the available bone and obtaining a good initial stability of the implant after maxillary sinus reconstruction. The maxillary sinus augmentation methods include a crestal approach and a lateral approach. Less morbidity and complications after operation is major advantage to sinus augmentation using crestal approach than lateral approach. However, when the residual ridge height is ${\geq}6mm$, it is known that crestal approach is appropriate. Also delayed implantation after sinus augmentation is recommended in severely atrophic ridge. We present the three cases of implant placement simultaneously sinus augmentation using crestal approach in posterior maxilla site with ${\leq}3mm$ of residual alveolar bone.

Case report of a newly designed narrow-diameter implant with trapezoid-shape for deficient alveolar bone (좁은 치조골에서 사다리꼴형 디자인으로 개발된 단폭경임플란트의 증례 보고)

  • Lee, Sa Ya;Goh, Mi-Seon;Ko, Seok-Yeong;Yun, Jeong-Ho
    • The Journal of the Korean dental association
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    • v.56 no.5
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    • pp.263-276
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    • 2018
  • Long-term survival and prognosis of narrow-diameter implants have been reported to be adequate to consider them a safe method for treating a deficient alveolar ridge. The objective of this study was to perform case report of narrow-diameter implants with a trapezoid-shape in anterior teeth alveolar bone. A 50-year-old male patient presented with discomfort due to mobility of all of the maxillary teeth and mandibular incisors. Due to destruction of alveolar bone, four anterior mandibular teeth were extracted. Soft tissue healing was allowed for approximately 3 months after the extraction, and a new design of implant placement was planned for the mandibular incisor area, followed by clinical and radiological evaluation. Implant placement was determined using an R2GATE surgical stent. The stability of the implants was assessed by ISQ measurements at the first and second implant surgery and after prosthetic placement. At 1 and 3 months and 1 year after implantation of the prosthesis, clinical and radiological examinations were performed. Another 50-year-old male patient presented with discomfort due to mobility of the mandibular central incisors. For the same reason as in the first patient, implant placement was carried out in the same way after extraction. ISQ measurements and clinical and radiological examinations were performed as in the previous case. In these two clinical cases, 12 months of follow-up revealed that the implant remained stable without inflammation or additional bone loss, and there was no discomfort to the patient. In conclusion, computer-guided implant surgery was used to place an implant in an optimal position considering the upper prosthesis. A new design of a narrow-diameter implant with a trapezoid-shape into anterior mandibular alveolar bone is a less invasive treatment method and is based on the contour of the deficient alveolar ridge. Through all of these procedures, we were able to reduce the number of traumas during surgery, reduce the operation time and total treatment period, and provide patients with more comfortable treatment.

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