Implant Treatment in Patient with Periodontitis: A Case Report with 13-year Follow-up.

This report describes long-term implant treatment in a patient with chronic periodontitis. The patient was a 59-year-old man who attended our facility requesting a dental implant. An initial examination revealed generalized gingival inflammation and subgingival calculus. Clinical examination revealed 55.3% of sites with a probing depth (PD) of >4 mm and 41.3% of sites with bleeding on probing. Radiographic examination revealed vertical bone resorption in #23, #33, #33, #35, and #47. Initial periodontal therapy consisting of plaque control, scaling and root planing, and tooth extraction was subsequently performed based on a clinical diagnosis of severe chronic periodontitis. Open flap debridement was performed for teeth with a PD >5 mm (#21, #22, #23, 333, #34, #35 and #47). After confirming the stability of the periodontal tissue, 3 implants were first placed in the maxilla (#25, #26, and #27). Final prostheses comprising a screw retaining-type implant superstructure were then placed (#25, #26, and 327). Following reevaluation, the patient was placed on supportive periodontal therapy. At 15 years after the first visit, the periodontal and implant conditions have remained stable. These results indicate that periodontal treatment before implantation and subsequent maintenance yield a clinically favorable and long-lasting outcome.

Clinical evaluation of periodontal pathogen levels by real-time polymerase chain reaction in peri-implantitis patients.

OBJECTIVE: The mechanisms underlying the onset and progression of peri-implantitis are similar to those of periodontitis, and the causative bacteria are believed to similar. Previous studies support an association between peri-implantitis and periodontal pathogen. Thus, we investigated the bacterial flora of peri-implantitis patients in comparison to those of healthy implant and periodontitis patients. MATERIALS AND METHODS: In total, 70 patients visiting Tokyo Dental College Chiba Hospital were divided into four groups: healthy, periodontitis, healthy implant, and peri-implantitis. For each group, the following five periodontal pathogens were detected using real-time polymerase chain reaction: Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Treponema denticola, and Prevotella intermedia. RESULTS: The average copy number of total bacteria was significantly higher in the periodontitis group than in the other groups. P. gingivalis was detected in the periodontitis and peri-implantitis groups at levels as high as 18.92% and 12.29%, respectively, and P. intermedia was found in the peri-implantitis group at a rate of 2.06%. Nevertheless, periodontal pathogens were generally detected at lower levels in the peri-implantitis group than in the periodontitis group. CONCLUSION: We found lower bacterial counts in the peri-implantitis group relative to the periodontitis group. Our results suggest that the peri-implant tissue is less resistant to bacteria, so even a small number of bacteria can be a risk factor for peri-implantitis and the causative agent of peri-implantitis can be bacteria other than periodontal pathogen.

Fatigue properties of hollow zirconia implants.

The objective of this study was to clarify the fatigue behavior of hollow yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) specimens assuming its use for two-piece implants. The fatigue properties of a solid specimen (which simulated a one-piece implant) and 3 types of hollow specimens (which simulated two-piece implants) were evaluated. Specimens were either solid with a diameter of 4.0 mm (S) or hollow with an inner diameter of 3.0 mm and outer diameters of 4.0 mm (H0.5), 4.5 mm (H0.75), or 5.0 mm (H1.0). For each group, 25 specimens were prepared followed by blast and acid etch treatment. Static fracture and cyclic fatigue tests were conducted by modifying the methods provided in ISO6872. Fracture modes were determined by observing the surfaces under a scanning electron microscope. As a result, the cyclic fatigue load of S and H1.0 were similar, and hollow specimens with outer diameters greater than 0.75 mm displayed the ability to withstand molar occlusal forces.

Effects of 2% sodium fluoride solution on the prevention of streptococcal adhesion to titanium and zirconia surfaces.

Streptococci are associated with dental plaque formation as the early-colonizing bacteria that adhere to titanium (CpTi) and zirconia (TZP) implant abutment surfaces. Effective prevention of peri-implantitis may be possible by removing streptococci as target. This study aimed to evaluate the effects of 2% NaF on the prevention of streptococcal adhesion to CpTi and TZP. After immersion in 2% NaF for 90 min, surface characterization of mirror-polished CpTi and TZP disks were assesed using XPS, EPMA, and SEM. S. sanguinis, S. gordonii, and S. oralis were used as the streptococcal bacterial strains. After 24 h culture, bacterial adhesion was evaluated using an ATP-bioluminescent assay and SEM. In XPS, EPMA, and SEM analyses, fluoride was detected on the CpTi and TZP surfaces after 2% NaF immersion with no signs of localization, and no corrosion on the CpTi disks. Based on the adhesion assay, the adherences of S. sanguinis, S. gordonii, and S. oralis were significantly lower with NaF than without NaF in CpTi (p = 0.005, 0.001, and 0.001, respectively) and TZP (p = 0.003, 0.002, and 0.001). This was also confirmed by SEM. In conclusion, 2% NaF reduced the adhesion of streptococci to the CpTi and TZP surfaces.

Influence of eccentric cyclic loading on implant components: Comparison between titanium and zirconia abutments.

The objective of this study was to investigate the effects of eccentric cyclic loading on implant components using the internal joint system with titanium and zirconia abutments. Abutments were made of either pure titanium (Ti group) or zirconia (TZP group). Cyclic loading test was conducted according to the specifications of ISO 14801. Loading condition was at 2 points assuming axial load and eccentric load. The reverse torque value reduced after the eccentric load and reduced more in the TZP group than the Ti group. Marginal gap changed after eccentric loading, and was greater in the TZP group. In the TZP group, changes in configuration were observed in the implant body, and Ti was detected on the abutment surface. From the above, the eccentric load may have worse effects than axial loads. It was suggested that the TZP group was clinically disadvantageous compared to the Ti group.

Wear properties of esthetic dental materials against translucent zirconia.

To clarify the influence of translucent tetragonal zirconia polycrystals (TZP) on wear properties of esthetic dental materials, two-body wear test was performed using translucent TZP as abrader specimen, and bovine tooth enamel (BTE), two resin composites including hybrid filler (CRH) and nano filler (CRN), two glass ceramics including leucite reinforced feldspar porcelain (POR) and lithium disilicate (LDC), or translucent TZP as substrate specimen. After the wear test, wear volume were determined from substrate specimen and surface roughness were measured from abrader specimen. In addition, Vickers hardness was measured and surface morphologies were observed after wear test using a scanning electron microscope. The wear volume of the esthetic dental material against translucent TZP was greater in glass ceramics (POR, LDC), smaller in resin composite (CRH, CRN) and BTE, and no wear in translucent TZP. Microstructures of the esthetic dental material may play a crucial role for wear behavior against translucent TZP.

Dental Implant Treatment with Computer-assisted Surgery for Bilateral Agenesis of Maxillary Lateral Incisors: A Case Report.

Here, we report a case of dental implant treatment involving computer-assisted surgery for bilateral agenesis of the maxillary lateral incisors. The patient was a 39-year-old woman with the chief complaint of functional and esthetic disturbance due to maxillary and mandibular malocclusion. The treatment plan comprised non-extraction comprehensive orthodontic treatment and prosthodontic treatment for space due to the absence of bilateral maxillary lateral incisors. A preliminary examination revealed that the mesiodistal spaces left by the absent bilateral maxillary lateral incisors were too narrow for implant placement (right, 5.49 mm; left, 5.51 mm). Additional orthodontic treatment increased these spaces to approximately 6 mm, the minimum required for implant placement if risk of damage to the adjacent teeth due to inaccuracies in directionality of drilling is to be avoided. For dental implant treatment with computer-assisted surgery, preoperative planning/simulation was performed using Simplant® ver.12 software and a toothsupported surgical template fabricated using stereolithography. Two narrow-diameter implants were placed in a two-stage procedure. It was confirmed that there was sufficient distance between the implant fixtures and the roots of the adjacent teeth, together with no exposure of alveolar bone. Following a 4-month non-loading period, second-stage surgery and provisional restoration with a temporary screw-retained implant crown were performed. Cement-retained superstructures made of customized zirconia abutment and a zirconia-bonded ceramic crown were fitted as the final restoration. At 5 years after implant surgery, there were no complications, including inflammation of the peri-implant soft tissue and resorption of peri-implant bone. Computer-assisted implant surgery is useful in avoiding complications in bilateral agenesis of the maxillary lateral incisors when only a narrow mesiodistal space is available for implant placement.

Proliferation and osteogenic differentiation of human mesenchymal stem cells on zirconia and titanium with different surface topography.

The purpose of this study was to elucidate behavior of human mesenchymal stem cells (hMSCs) on yttria stabilized tetragonal zirconia polycrystals (TZP) and commercial pure titanium (CpTi) with different surface topography. Mirror-polished (MS), sandblasted with 150-µm alumina (SB150) and SB150 acid-etched (SB150E) were prepared on TZP and CpTi. Proliferation, osteogenic differentiation of hMSCs was evaluated. The scanning electron microscopy showed that micro- and nano-topographies were created on both TZP and CpTi SB150E surfaces. The proliferation ability, ALP activity, expression of Runx2 on the both SB150E specimens was significantly higher than those on the other specimens. These results suggested that creation of micro- and nano-topographies on TZP and CpTi by blast and acid-etching may offer a promising method for enhancing the proliferation and differentiation of hMSCs in clinical application.