The low-level laser irradiation (LLLI) therapy for bone healing has attracted strong interest in the field of clinical implantology. It has been reported that LLLI on bony implant sites might have positive effects on the integration of implants. The biostimulatory effect of bone formation by LLLI has been investigated, however, very little is known about the molecular basis of biostimulatory mechanisms. Since LLLI will be useful to support implanttherapy, it is important to elucidate the mechanism of biostimulatory effect of LLLI on bone formation.
We previously constructed a cDNA library of mouse osteoblastic cells (MC3T3-E1), which enhanced gene expression by LLLI using a subtracted gene cloning technology. In the present study, we analyzed the DNA nucleotide sequence of gene clones MCL-176. The nucleotide sequence of MCL-176 DNA insert was determined and assessed in the standard nucleotide-nucleotide BLAST homology-search using NCBI DNA databases. DNA nucleotide sequences of clone MCL-176 cloned DNA exhibited high homology with macrophage(migration) inhibitory factor (MIF) gene. Reverse-transcription real-time PCR analysis showed that MIF mRNA level was enhanced by LLLI. MIF is known as a cytokine that mediates inflammatory processes in a variety of tissues. Since it has been reported that MIF is also presented in osteoblasts and MIF modulates the proliferation of osteoblasts, MIF is involved in the growth of osteoblasts and bone tissue remodeling. Our findings suggest that LLLI may enhance MIF mRNA transcription of osteoblasts and play a role in the osseous metabolism.
Purpose: This study examined the accuracy of fit, aiming to increase the preloading of the keeper of a magnetic attachment for implants, and to improve an appropriate tightening torque.
Materials and methods: The keeper for the magnetic attachment newly developed for 3i, the Nobel Biocare (hereafter, NB), and the ITI system was evaluated.Two kinds of attachment were prepared (type A and type B with different shape). The accuracy of fit was examined with SEM and a microscope. The 3i and the NB system measured the space between the abutment ring and the keeper during the fixture and the abutment ring in type A. The ITI system measured the space between the fixture and the keeper. In type B, the keeper of 3i and NB was shared. Therefore, the space was measured with the 3i fixture by using a similar method to that used for type A. The space in the abutment of each system was measured as a control. An appropriate tightening torque of the keeper screw to prevent the screw from becoming loose was assumed to be 70% of the destruction value that had been obtained from the tightening examination. Five materials were used for each examination.
Results: The distance was 4.40 μm (SD:1.37) between the keeper and the abutment in type A for 1.19 μm (SD:0.65) for 6.01 μm (SD:2.03) for 3i and NB and ITI, and meanwhile, it was one side and 10.6 μm (SD:1.98) in the control for 13.4 μm (SD:1.40) for 1.33 μm (SD0.447) for 3i and NB and ITI. They were 4.66 μm (SD1.35) between the abutment ring and the keeper and 5.96 μm (SD:2.83) between the fixture and the abutment ring in type B for 3i. Then, it was 1.72μm (SD:1.01) between the fixture and the keeper for ITI.
Discussion: An appropriate tightening torque is 50-70% of the maximum tightening power at which the screw was destroyed. The proper tightening torque calculated
referring to this was 15 Ncm, and, then, 20 Ncm in type A then for ITI for 3i and for NB. Both 32 Ncm was possible in type B.
Conclusion: Appropriate agreement was obtained, and an increase in preloading was obtained by improving the tightening torque according to the improvement. As a result, it is thought that keepers for preventing magnetic attachment from becoming loose could be improved.
Introduction: Single standing implants have become an increasingly used treatment option and some studies reported favorable results. However, for the incisor area for single standing implants, it is sometimes difficult to get an optimal and long-lasting esthetic outcome compared to the molar area, so in the incisor area, prosthetic considerations have been discussed.
The aim of this study was to identify some differences in periodontal view between the incisor area and molar area concerning single standing implants.
Material and method: 27ITI Bonefit® implants which had been functioning for more than five years were selected for this study. They were checked from various aspects, especially periodontal point of view, and their statistical data were compared to data of the molar area.
Result: The most common implant site was the upper incisor area, and the most common implant size was 3.3 mm in diameter and 14 mm in length.
As for complications, screw loosening and peri-implant-mucositis were observed, but severe complications such as loss of osseo-integration or loss of attachment were not observed.
Periodontal parameters show that the BOP score and the change of DIB were slightly higher than the data in the molar area which we had already reported prior to this study, but there were no statistically significant differences between them.
Conclusion: The results suggested that single standing implants in the incisor area would be safe and predictable even from a periodontal point of view.
From April 1996 to March 2003, 34 patients with unsuccessful implants, which had been placed at other clinics,were treated in the Section of Oral Implantology of the Facilitated Hospital of Fukuoka Dental College.
The subjects were 23 females and 11 males, ranging inage from 48 to 80 years. Sixteen of the patients were in their 50s and 12 were in their 60s. In total, 62 implants were removed from 34 patients. These 62 implants included 13 Sapphire screw implants,13 metal blade implants, 5 Sapphire blade implants, 14 titanium endosseous implants, 15 hand-made metal implants, one subperiosteal frame implant and one bioglass implant.
After removal of these unsuccessful implants, 20 patients wanted their dentition to be restored with implant supported prostheses. Sixteen underwent implant restoration, 2 are currently waiting for wound healing, and 2 received removable dentures because of economic conditions and severe bone loss.
In total, 109 implants were placed in these 16 patients. Twenty-seven were placed in the same place as the implants that were removed and the length of these 17 implants was under 10 mm. One implant, which had been placed in the mandibular first molar site after removal of an infected implant, was lost because of infection 1 month after placement.
We investigated the hygiene of 13 overdentures with implant abutments. Plaque was checked with a plaque disclosing agent and Candida albicans was detected by Stomastat®.
1. A little plaque was detected on the labial side and the interior of the bottom side of the cap on the implant bodies. However, much plaque was detected on the lingual side, the soldering parts and the bottom of the connetting bar.
2. Much plaque adhered to the clip parts at the mucosal side of the denture.
3. Candida albicans were detected on the bottom of the connecting bar and on the parts of the clips at the mucosal side of the denture. It is important to clean the dentures as well as the implant abutments, because denture stomatitis can occur in the clip parts with Candida albicans.
Purpose: We report that a mentally disabled patient's masticatory function and esthetics were improved by applying the implant overdenture system by using a magnetic attachment.
Case: The patient was a 56-year-old female. The chief complaint was disturbance of masticatory function because of ill-fitting of the upper jaw denture. The case was complicated because the patient was seriously mentally disabled and attended an institution for the mentally disabled in daily life. Oral findings were edentulous upper jaw 2 years ago and the lower jaw had only 2 teeth.The alveolar bone of the upper jaw showed remarkable bone resorption and the tongue and lips showed extramovement.
Operation and Course: We performed surgical insertion of 7 ITI® implants around the 832｜2378 regions under intravenous sedation. Six months later, we carried out a second operation to implant the Platon® magnetic head system, and then completed the upper overdenture without palatal base by using the magnet of Hitachi® High Colex. After completing the overdenture, the patient showed remarkably improved masticatory function and esthetics, and reduced extra-movement of the tongue and lips. We are now performing a regular check-up every three months.
Discussion and Conclusion: We found that implantation for the mentally disabled patient involved many difficult factors such as whether the implant was done by surgical operation or not, and maintenance of oral condition was poor because of poor oral hygiene. In this case, the implant overdenture system by using magnetic attachment was shown to improve QOL for the mentally disabled patient and was very useful.
A 45-year-old male visited our clinic with a chief complaint of masticatory disturbance due to edentulism of the left maxillary molars and the right second maxillary premolar, and due to marginal problems around the left mandibular second molar. Because of bone loss at the edentulous left posterior maxilla, inadequate bone was available for implant anchorage. A sinus grafting was indicated in this patient. Bone was harvested from the symphyseal area and grafted to the left maxillary sinus floor after a sinus lift procedure. At 11 months after an adequate amount of bone material was confirmed, the placement of an endosseous implant (8 mm in length) was performed. Just after the placement of the implant, a periapical radiolucent lesion of the left maxillary second premolar adjacent to the procedure area was noted.The patient had no symptoms of any pain. The affected tooth had been checked regularly for devitalization by use of an instrument for pulp diagnosis and was thought to be vital. Following a 6 month-period of integration, the implant was uncovered and an abutment was placed and loaded with a fixed prosthesis. Incorporation of the implant was evaluated by clinical and radiographical examinations just after the abutment was placed and every year thereafter. An internal dental fistula appeared at the buccal gingival mucosa approximately five years after the sinus grafting, which was consistent with the periapical radiolucent lesion. The affected tooth was checked during a regular examination with the use of an instrument for pulp diagnosis and judged to be devitalized. Endodontic therapy on the devitalized tooth was performed. Placing the sinus lift augmentation too close to an apically natural tooth may result in adevitalized tooth. Therefore, a follow-up of the placement of an implant combined with sinus lift augmentation at regular intervals is very important.