Mechanical and Spectroscopic Analysis of Retrieved/Failed Dental Implants

Antimicrobial Capacity and Surface Alterations Using Photodynamic Therapy and Light Activated Disinfection on Polymer-Infiltrated Ceramic Material Contaminated with Periodontal Bacteria

This study determined the antimicrobial efficiency of light-activated disinfection (LAD) and photodynamic therapy (PDT) on polymer-infiltrated ceramic network (PICN) material contaminated with three periodontal bacteria and explored if PDT and LAD cause PICN surface alterations. Sixty PICN discs were contaminated with Tannerella forsythia, Porphyromonas gingivalis, and Treponema denticola and randomly divided into five groups (n = 12 samples/each) according to the treatment groups: Group PDT-PDT (630 ± 10 nm diode laser) with methylene blue; Group DL-808 nm diode laser in contact mode without photosensitizer; Group MB-methylene blue without light application; Group CHX-0.12% chlorhexidine digluconate solution and; Group NT-no treatment. Each disc was then placed in tubes containing phosphate buffered saline (PBS) and vortexed for 30 s to remove the remaining bacteria from the discs. A total of 10× serial dilutions were performed followed by plating of 30 μL of suspension on Brucella agar plates. The colony forming units (CFU) were calculated after 72 h. PICN discs with the attached biofilms were used for confocal microscopy investigation for live/dead bacterial viability. A random single sample from each group was selected to study the bacterial adherence and topographical alterations on PICN discs under scanning electron microscope (SEM). The PDT group showed higher reduction for each bacterial species and total counts of bacteria assessed followed by the DL group (p < 0.05). When compared with MB group, the two laser groups were significantly superior (p < 0.05). The MB group did not show significant differences for any bacteria when compared to NT. The bacteria with the CHX group and DL groups appeared dead with few areas of surviving green stained bacteria. The PDT group showed the highest dead cell count (p < 0.05). PDT and DL groups indicate no significant changes on the surface compared to the sterile PICN discs on visual assessment. Photodynamic therapy produced superior periodontal bacteria reduction over the surface of PICN surface. PDT group showed higher reduction for each bacterial species and total counts of bacteria assessed followed by the DL group. Both PDT and DL treatment strategies are effective without producing surface alterations on PICN.

Spectroscopic Methods Used in Implant Material Studies

It is recognized that interactions between most materials are governed by their surface properties and manifest themselves at the interface formed between them. To gain more insight into this thin layer, several methods have been deployed. Among them, spectroscopic methods have been thoroughly evaluated. Due to their exceptional sensitivity, data acquisition speed, and broad material tolerance they have been proven to be invaluable tools for surface analysis, used by scientists in many fields, for example, implant studies. Today, in modern medicine the use of implants is considered standard practice. The past two decades of constant development has established the importance of implants in dentistry, orthopedics, as well as extended their applications to other areas such as aesthetic medicine. Fundamental to the success of implants is the knowledge of the biological processes involved in interactions between an implant and its host tissue, which are directly connected to the type of implant material and its surface properties. This review aims to demonstrate the broad applications of spectroscopic methods in implant material studies, particularly discussing hard implants, surface composition studies, and surface-cell interactions.

Clinical and radiographic indices around narrow diameter implants placed in different glycemic-level patients

BACKGROUND

Studies assessing peri-implant clinical and marginal bone resorption (MBR) around narrow diameter implants (NDIs) placed in different glycemic levels are uninvestigated.

OBJECTIVE

The present 3-year retrospective follow-up investigation was designed to explore clinical and radiographic status of NDIs placed in individuals with different glycemic control levels.

MATERIALS AND METHODS

Patients with serum hemoglobin A1c (HbA1c) levels ≥6.5% (Group-1), 5.7%-6.4% (Group-2), and 4.0%-5.0% (Group-3) were included. Clinical indices evaluating bleeding on probing (BOP), plaque scores (PI), peri-implant probing depth (PD), and MBR were recorded around NDIs at 1-, 2-, and 3-year follow-up. Serum HbA1c test was carried out for all patients to assess the profile of glycosylated hemoglobin at 1 and 3 years of follow-up.

RESULTS

A significant reduction in mean HbA1c levels from year 1 to year 3 follow-up period was seen in Group-1 only. PI varied from 0.40 in Group 1 at 2 year and 0.42 at 3-year follow-up to 0.18 at 2-year (P = 0.032) and 0.17 at 3-year (P = 0.018) follow-up, respectively. Greater BOP was noted in Group 1 (0.53) as compared with Group 2 (0.42) and Group 3 (0.21) (P = 0.048) at 3-year follow-up. PD after 3 year ranged from 2.04 mm in Group 3 to 2.32 mm in Group 1 that showed statistically significant difference (P = 0.037). No statistical significant differences were observed in MBR at any time point between the groups.

CONCLUSION

The results of this short-term follow-up study indicate that NDIs show clinical and radiographic stability, provided oral cleanliness and glycemic levels are relatively maintained. Further long-term clinical studies are needed to evaluate implant stability over the period along with controlled glycemic status.