The Japanese Society of Oral Implantology is the largest academic-clinical society in dentistry in Japan with a membership of 12,000 dental surgeons. Activities that are held under the Society's auspices range from academic conferences on the basic dental science of oral implant technology to gatherings that deal with highly clinical aspects thereof. The Society keeps close ties with its partners overseas on levels that range from Society-to-Society, interuniversity or interfaculty, to person-to-person, with active real-time exchanges regarding treatment methods, techniques and materials backed by the most recent theory and insight. The Society considers it obligatory for a dental surgeon to provide patients with the optimum implant treatment based on science, and that is least invasive and safe.
A licensed dentist who is practicing or is about to practice dentistry in Japan must be law-abiding and ethical in performing therapeutic work for patients. Japanese dentists must comply with the Pharmaceutical Affairs Law and the Medical Service Law as well as the Dental Practitioners Law, and must also faithfully observe ethical guidelines that were instituted to protect the rights and health of the patient.
This paper first discusses those ethical aspects of oral implant research that are prerequisite to any level of research into the basic dental science or clinical aspects of this technology. It then reports on the laws and guidelines that dental surgeons in Japan must abide by.
With the aim of developing a new type of non-resorbable membrane for guided bone regeneration (GBR) that could promote bone formation, a surface-modified poly(ethyleneterephthalate)(PET) sheet coated with a double layer of gelatin and calcium phosphate was prepared and the response of MC3T3-E1 cells was investigated. The material was prepared through the following steps: surface hydrolysis of PET sheet, covalent bonding of a gelatin layer, immobilization of urease, and deposition of calcium phosphate layer with the mediation of urease at 310 K. The gelatin layer was very thin and the calcium phosphate layer was 5 to 10 μm thick. The calcium phosphate layer consisted of octacalcium phosphate (OCP) and low-crystallinity hydroxyapatite (HA) , and dissolved in saline up to the saturation concentration within one day. MC3T3-E1 cells were cultured on untreated PET, PET coated with gelatin (PET/gel), and PET coated with gelatin and calcium phosphate (PET/gel/CaP) for up to 60 days. Although the cells did not attach on untreated PET, they attached and proliferated on PET/gel. The proliferation was more pronounced on PET/gel/CaP. In addition, deposition of calcium salts was evidenced by von Kossa staining on PET/gel/CaP. The calcium phosphate layer was considered to act as one of the supply sources of calcium ions to assist the differentiation of MC3T3-E1, and the gelatin layer may have acted as the platform for the attachment and proliferation of the cells. The present material is therefore considered to be a promising candidate for a non-resorbable GBR membrane that could assist bone formation.
Objective: Primary stability is essential for achieving osseointegration after bonding an implant to the marginal bone. Successful implant osseointegration can be determined by assessing the relationship between preoperative bone quality and initial stability. We investigated the clinical and statistical relationship between bone analysis by preoperative CT images and implant mobility.
Methods: The periotest (PT) value was measured in the teeth of 64 patients (31 men, 33 women) who had preoperative CT scans between October 2007 and March 2011. We used CAMLOG implants. PT-values were measured using the following Periotest. CT scan devices: Aquilion16, Aquilion32, Asterion, and LightSpeed Ultra16. CT-number of the stent with gutta-percha points attached to the patient during scanning was converted into measurements. Cortical bone CT-number (CHU), cortical bone thickness (CW), and cancellous bone CT-number (SHU) were measured at the implant site. These numbers were compared to the PT-value of an implant body placed in the same site.
Results: The overall median PT-value was －3.0. CHU was 1,048.1 HU, CW was 1.3 mm, and SHU was 581.0 HU. PT-value showed a strong correlation in the cortical bone. Correlation coefficients were rs=0.51(CHU) and rs=0.70 (CW) .
Conclusions: CT-number and thickness of the cortical bone were correlated with initial implant mobility. In preoperative CT scanning, measuring the CT-number and thickness of the cortical bone around an implant is effective for determining the stability of the implant osseointegration.
A case of emergency tracheotomy following life-threatening hemorrhage in the floor of the mouth during routine dental implant placement in the mandibular canine region is described. The patient was a 53-year-old male who was treated with dental implants for missing teeth at a private dental office. Placement of implants in the anterior mandibular region is generally regarded as a routine, simple and safe procedure, but incidents of severe bleeding and hematoma in the floor of the mouth have been reported as a potentially fatal complication related to the placement of an implant in this region. Perforation of lingual cortical bone may lead to life-threatening hemorrhage because the floor of the mouth contains branches of the submental and sublingual arteries. This report demonstrates the importance of managing acute airway problems resulting from such perforations. The operator must be alert to the possibility of life-threatening hemorrhage when placing an implant in the anterior region of the mandible. If perforation happens, it is advisable to send the patient to an appropriate medical institution even if hemorrhage and/or swelling has not occurred.
The postoperative prospects of implant treatment depend on many factors, especially the number of missing teeth.
In this study, we examined the factors related to the number of missing teeth in implant patients at the first visit.
The subjects were 27 patients who visited the oral implantology department of Osaka Dental University Hospital. The number of bacteria in periodontal pockets, saliva tests, status of teeth, periodontal tissue and oral hygiene were examined by four calibrated dentists. Moreover, the subjects were asked about their lifestyle and oral health behavior.
The number of missing teeth was statistically correlated with not only the number of P. intermedia and P. gingivalis in the periodontal pockets, but also regularity of having breakfast and oral health activities.
These results showed that the number of missing teeth is an indicator of various factors affecting the number of bacteria in periodontal pockets and the lifestyle of implant patients.
It is suggested that implant treatment and health counseling in consideration of the number of missing teeth are necessary in clinical practice.
The purpose of the present study was to determine the rate of alveolar bone resorption in maxillary and mandibular edentulous regions assessed by cone-beam CT. The height and width of alveolar bone in the molar regions were respectively compared to the control edentulous sides.
The subjects were 36 patients who were analyzed prior to dental implant surgery using a cone-beam CT scanner (XP62 Finecube, Yoshida Dental Manufacturing Co.) in standard imaging mode. To perform the measurements, a line was set perpendicular to the axis of the second premolar, and the measurement positions were set 5 mm distal to the intersection of alveolar bone margins from the distal surface of the second premolar. The height of alveolar bone was measured parallel to the axis of the second premolar, while the width was measured 1.5 mm basolateral to the alveolar bone crest.
The study findings were as follows: (1) the height of upper alveolar bone on the edentulous side differed significantly from that on the control side (p＜0.05), and the bone resorption rate was 27%; (2) the width of upper alveolar bone on the edentulous side was significantly different from that on the control side (p＜0.05), and the bone resorption rate was 33%; (3) the height of lower alveolar bone on the edentulous side did not differ significantly from that on the control side, and the bone resorption rate was 5%; (4) the width of lower alveolar bone on the edentulous side was significantly different from that on the control side (p＜0.05), and the bone resorption rate was 32%; (5) comparisons of upper and lower alveolar bone height revealed that lower alveolar bone was significantly larger than upper alveolar bone on both the edentulous side and the control side.
These findings demonstrate that the height of lower alveolar bone hardly changed even if teeth were missing. However, the height of upper alveolar bone, the width of upper alveolar bone and the width of lower alveolar bone become smaller due to missing teeth.
The process of bone regeneration on artificial mandible defects was evaluated after implanting titanium frame coated hydroxyapatite and fluoride-treated bioresorbable synthetic hydroxyapatite granules with a combination application of fluoride (4% NaF: 18,000 ppmF) and platelet-rich plasma (PRP) .
The titanium frame along with the surrounding bone was surgically removed four months after implantation and the crystal structure of the bone surface was measured by micro area X-ray diffraction (μ-XRD).
The two-dimensional μ-XRD pattern in the F-treated sample showed that the noise dispersion patterns of HA at 26.4 degrees, 28.6 degrees, 30.2 degrees, 36.1 degrees and 41.0 degrees had disappeared, which confirmed our in vitro data. Taken together with previous experiments, our study suggests that bioresorbable synthetic HA granules may improve the crystalline quality, although the unidentified pattern was considered to represent the existence of Monetite (CaPO3 (OH)) in the bioresorbable synthetic HA granules.
Therefore, the present results show that fluoride-released bioresorbable synthetic HA granules could be a promising method for clinical usage.
The purpose of the present study was to compare preoperative data from examinations, including (1) electrocardiogram (ECG) , (2) chest X-ray, (3) blood tests, (4) urinalysis, and (5) blood pressure with medical history completed by patients.
The subjects were 178 patients who presented to our department for implant treatment between January 2008 and December 2009. They were 66 men and 112 women (mean age: 57.0± 13.20 years). Comparisons were made between preoperative test results and the contents of preoperative medical history forms.
The results of this clinical investigation were that 53 patients answered "yes" to the question, "Do you have a chronic disease or a recently diagnosed disease?" These included 24 patients with hypertension, 7 patients with diabetes, 9 patients with heart disease, 2 patients with cerebral infarction, and 2 patients with thyroid disease. There were 125 patients who answered "no" to this question, of whom 75 had abnormal test results. They included 2 patients with positive HBs antigen results, 2 patients with positive HCV antibody results, and 2 patients with TPHA positive results. There were 11 patients whose fasting glucose level exceeded 110 mg/dL. There were 29 patients who had abnormal ECG results and required intraoperative ECG monitoring. One among these patients underwent re-examination using a Holter ECG system. Careful intraoperative monitoring and countermeasures for arrhythmia were indicated in this patient based on the re-examination results. In addition, two patients developed intraoperative arrhythmia despite no abnormal preoperative test results. Twenty-eight patients had systolic blood pressure of 140 mmHg or more and diastolic pressure of 90 mmHg or more at a preoperative evaluation. There were 2 patients whose surgery was cancelled based on their attending internist's decision. One patient had sick sinus syndrome and the other had severe diabetes.
A high percentage of patients (60%) had abnormal test results despite their answering "no disease" in the medical history form. If systemic health problems are overlooked, patients can develop intraoperative abnormalities, postoperative infection, or other complications. Our results suggest that a preoperative medical history form alone should not be used to fully evaluate systemic health, and indicate the importance of preoperative tests.