The purpose of this study was to examine the effects of tooth surface embrocation of fluoride products (TSEF) on titanium surface properties and their effects on gingival tissues. First, titanium discs were totally covered with commercially available TSEFs including 9,000 ppm fluoride (pH 3.5-8.0), then the specimens were incubated for 4 min. The tarnish and surface roughness before and after the incubation with TSEFs were analyzed by color difference meter and surface roughness meter, respectively. Next, the accumulated amount of Ti ions released into gingival tissues from the implant exposed to TSEFs (9,000 ppmF, pH 3.5) was measured using inductively coupled plasma mass spectrometry (ICP) . Moreover, the responses in gingival tissues to released Ti ions and/or Porphyromonas gingivalis-lipopolysaccharide (P.g.-LPS) were measured. There were significant differences in color stability and surface roughness of the titanium surfaces exposed to TSEFs including 9,000 ppm fluoride (pH 3.5-4.0), compared to those of pure water and TSEFs including 9,000 ppm fluoride (pH 6.0-8.0) (ANOVA, **p＜0.01, *p＜0.05). More Ti ions were detected in the gingival tissues around the implant after treatment with TSEF including 9,000 ppm fluoride (pH 3.5) than those without the same TSEF (ANOVA, *p＜0.05), which suggests that the fluoride corroded the implant surface under salivary buffering capacity. The injection of P.g.-LPS in the presence of released Ti ions significantly increased the mRNA expression of chemokine (C-C motif) ligand 2, and receptor activator of nuclear factor-lB ligand, in rat gingival tissues (ANOVA, **p＜0.01, *p＜0.05). These data suggest that TSEF of lower pH corroded the Ti surface and its released Ti ions may be partly responsible for the infiltration of monocytes and osteoclast differentiation by increasing the sensitivity of gingival epithelial cells to endotoxin in the oral cavity.
Objectives : This study aimed to reveal the effect of maxillary sinus floor augmentation (“sinus lift”) on the maxillary sinus by examining changes in the thickness of the maxillary sinus mucosal membrane (MSM). Here, we report interesting findings.
Materials and Methods : The subjects were 30 patients (54 fixtures or sites) who had undergone piezoelectric surgery (piezosurgery) for sinus lift and concurrent implant placement using a lateral approach. The mean age of patients was 53.6±14.5 years. Dental cone beam computed tomography (CBCT) was performed at the time of preoperative examination and postoperatively at 7.6±2.4 months (range, 4.7-14.5 months) before the second stage of surgery. Coronal and sagittal images were acquired for the measurement of MSM thickness in implant sites (maximum thickness in a 10-mm square covered by the buccal, lingual, mesial, and distal margins). Statistical analysis was performed to compare MSM thicknesses between the preoperative and postoperative groups and between different implant material groups (autologous bone, artificial bone, and no bone graft groups). MSM was also examined in patients with intraoperative maxillary sinus perforation to evaluate healing.
Results : Mean preoperative and postoperative MSM thicknesses were 1.54±1.33 and 2.27±1.50 mm, respectively, with a significant difference between the groups (p＜0.01, Wilcoxon signed-rank test). The mean increment in the MSM thickness after surgery was 0.70±1.21 mm. The thickness of MSM postoperatively increased in 30 sites (60%) but decreased in 5 sites (10%) . Intraoperative perforation was observed in 3 sites (5.6%).
Discussion and Conclusion : In many implant sites, the MSM thickened after sinus floor augmentation in response to surgical stimuli. However, no significant changes due to different implant materials were observed. In the cases of intraoperative perforation, marked thickening of the MSM was noted immediately after surgery. When no maxillary sinus infection was observed within several months after surgery, the MSM steadily returned to its original thickness. The present findings show that careful observation of the MSM is an important means to judge post-perforation healing.
Recovery of oral function with dental implants is clinically effective and highly predictable. The quantity and quality of bone at the implant installation site affect the prognosis, however, the effects of bisphosphonates (BP) on mandibular bone have not been well documented. The purpose of this study was to evaluate the effect of bisphosphonates on bone mineral density (BMD) and cortical width (CW) of the mandible.
The subjects were 41 female patients with a partially edentulous molar region of the mandible. Seventeen BP cases and 24 controls were evaluated. Cortical and trabecular BMD was measured with quantitative computed tomography (QCT). CW was measured with CT. The BMD and CW of the two groups were compared.
The results were as follows.
1. The use of oral bisphosphonates affected early implant failure rates.
2. Cortical BMD was significantly high in the BP group.
3. Trabecular BMD was not affected by BP.
4. CW was affected by the duration of taking BP.
These results indicate that BP affects the quality and quantity of cortical bone of the partially edentulous molar region of the mandible in patients with osteoporosis, which should be considered in dental implant treatment for patients taking BP.
Oral implantology seminars have been held across Japan, and we have 30 years of experience of organizing such seminars. In this study, we conducted a questionnaire survey of the changes in participants' attitudes toward oral implantation and examined the survey results. The subjects were 380 individuals who had participated in a seminar organized by our center. The questionnaire consisted of questions on the following 10 items : (1) purpose of participation ; (2) employment status at the time of participation ; (3) experience of dental treatment using implants ; (4) membership status of the Japan Society of Oral Implantology ; (5) membership status of the Japan Dental Association ; (6) objectives after participating in the seminar ; (7) positive attitudes toward dental implant treatment after participating in the seminar ; (8) technical challenges encountered in dental implant treatment after participating in the seminar ; (9) acquisition of new knowledge through the seminar ; and (10) long-term considerations, such as when patients with dental implants become elderly and require longterm care.
In training institutions for dental implants, operative cases should be allocated on the basis of the surgeon's experience and skill set ; appropriate case selection both safeguards patients and allows the trainee to amass experience and skills to be an accredited implant specialist. Currently, case selection relies on the subjective judgment of the senior surgeon and objective measures are not usually employed. The aim of this study was to introduce a new system which we developed from objective criteria to measure the surgical complexity of operative cases, and to classify the clinical cases in comparison with the SAC classification (Classification of the Swiss Society of Oral Implantology (1999) ; “SAC”) and subjective classification by experts.
Three tiers of operative difficulty (Beginner, Middle, Senior Classification ; BMS Classification) were established using five levels of five elements to give a total BMS score of 5-25 points. The five elements were Function, Aesthetics, Number of implants, Strength and Duration, which were given a score of 1 to 5 points each. Cases with a total score of 5-7 were classified into Beginner (B), those with a score of 8-13 were classified into Middle (M), and those with a score of 14-25 were classified into Senior (S), and the condition to be an operator for cases of each stage is determined by the number of surgeries assisted or performed.
Preoperative clinical records of 80 implant surgery cases performed at Showa University Dental Hospital from November 2012 to December 2013 were extracted and analyzed retrospectively. These cases were classified by both the BMS and SAC Classification and in addition, the BMS scores of the cases that were assigned to two beginner dentists in their first year and two senior dentists were evaluated. The 80 cases were classified into S : 65%, A : 17.5%, and C : 17.5% by SAC, and B : 26%, M : 49%, and S : 25% by BMS. Approximately 50% of S stage cases by SAC were classified into M stage by BMS. The majority of the cases assigned to the beginner dentists were classified into B stage, and those of senior dentists were classified into M or S stage.
The results of this preliminary study suggest that the new classification system has excellent ability to identify cases suitable for beginner surgeons, which might be of particular benefit to educational institutions that can use the same system to allow step-wise progression to more advanced cases in an objective and logical manner.