Ivona Bago

Comparison of Er:YAG Laser and Surgical Drill for Osteotomy in Oral Surgery: An Experimental Study

PURPOSE High-energy lasers have been proposed as an alternative to the conventional surgical drill in oral and maxillofacial surgery. The aims of this study were to compare thermal changes of the bone surface, procedure time, and volume of the removed bone after drilling with an erbium (Er):yttrium-aluminum-garnet (YAG) laser versus a low-speed surgical drill. The bone sections were observed under light microscopy and examined histologically. MATERIAL AND METHODS Thirty bone blocks were prepared from porcine ribs. On each block 2 holes (tunnel preparations) were performed using a low-speed, 1.0-mm-wide, surgical pilot drill and an Er:YAG laser (pulse energy, 1,000 mJ; pulse duration, 300 μs; frequency, 20 Hz). The temperature induced by the preparation techniques was measured using an infrared camera. The removed bone volume was calculated by a modified mathematical algorithm. The time required for the preparation was measured with a digital stopwatch and a time-measurement instrument integrated within the computer program. The cortical and spongiose surfaces of the specimens were examined microscopically and histologically under a light microscope with a high-resolution camera. RESULTS The Er:YAG laser removed significantly more bone tissue than the drill (P < .01) in a significantly shorter time (P < .01). The temperature was statistically lower during the laser preparation (P < .01). Cavities prepared with the laser were regular with clear sharp edges and knifelike cuts. In the drill group, the preparations exhibited irregular edges full of bone fragments and fiberlike debris. Histologic examination of the laser sides showed a 30-μm-thick altered sublayer. The tissue in the drill group was covered with a smear layer without any alterations. CONCLUSIONS The Er:YAG laser produced preparations with regular and sharp edges, without bone fragments and debris, in a shorter time, and with less generated heat. Thermal alterations in the treated surface were minimal.

Clinical Effectiveness of Diode Laser Therapy as an Adjunct to Non-Surgical Periodontal Treatment: A Randomized Clinical Study

BACKGROUND The aim of this randomized clinical study is to evaluate the effect of a 980-nm diode laser as an adjunct to scaling and root planing (SRP) treatment. METHODS Thirty-five patients with chronic periodontitis were selected for the split-mouth clinical study. SRP was performed using a sonic device and hand instruments. Quadrants were equally divided between the right and left sides. Teeth were treated with SRP in two control quadrants (control groups [CG]), and the diode laser was used adjunctively with SRP in contralateral quadrants (laser groups [LG]). Diode laser therapy was applied to periodontal pockets on days 1, 3, and 7 after SRP. Baseline data, including approximal plaque index (API), bleeding on probing (BOP), probing depth (PD), and clinical attachment level (CAL), were recorded before the treatment and 6 and 18 weeks after treatment. Changes in PD and CAL were analyzed separately for initially moderate (4 to 6 mm) and deep (7 to 10 mm) pockets. RESULTS The results were similar for both groups in terms of API, BOP, PD in deep pockets, and CAL. The laser group showed only significant PD gain in moderate pockets during the baseline to 18-week (P <0.05) and 6- to 18- week (P <0.05) periods, whereas no difference was found between LG and CG in the remaining clinical parameters (P >0.05). CONCLUSION The present study indicates that, compared to SRP alone, multiple adjunctive applications of a 980-nm diode laser with SRP showed PD improvements only in moderate periodontal pockets (4 to 6 mm).

The effectiveness of systemic eradication therapy against oral Helicobacter pylori

BACKGROUND Helicobacter pylori infection is associated with numerous gastroduodenal diseases. The oral cavity could be a potential extragastric reservoir for H. pylori, and oral H. pylori might cause gastric reinfection after the eradication therapy. The aim of the study was to evaluate the presence of H. pylori in oral cavity of patients with gastric H. pylori infection and to examine the effectiveness of the eradication therapy against H. pylori in stomach and in the oral cavity. METHODS Fifty-six patients with chronic periodontitis and gastric H. pylori were enrolled in the study. Gastric H. pylori infection was determined using (13) C-urea breath test before and 3 months after eradication therapy. The presence of the oral H. pylori was assessed using polymerase chain reaction before and 3 months after eradication therapy. The 1-week eradication therapy consisted of amoxycilin 1 g, clarithromycin 500 mg, and proton pump inhibitor 20 mg twice a day. RESULTS Of 56 subjects with gastric infection, 23 (41.1%) harbored H. pylori in the oral cavity. Eradication rate in stomach was 78.3%, whereas in the oral cavity, H. pylori was not detected from any sample after the eradication therapy. CONCLUSION Almost half of the patients with gastric H. pylori harbored the bacterium in the oral cavity. After the eradication therapy, H. pylori was not detected in the oral cavity, what suggests high effectiveness of the therapy protocol in the oral cavity, or it is possible that oral H. pylori is of a transient character.

Application of Diode Laser in Oral and Maxillofacial Surgery

Laser devices have gained in importance since the eighties and they are often claimed to be omni-use instruments. Though many applications turned out to be almost impracticable, an unaltered interest in laser technology has remained to date. The broad spectrum of applications for the diode laser means that it is now the most widely used device in laser dentistry. Diode lasers offer an interesting – but not unlimited – field of application in modern dentistry: oral and maxillofacil surgery and endodontic surgery.

Antimicrobial efficacy of photodynamic therapy and light-activated disinfection on contaminated zirconia implants: An in vitro study

BACKGROUND We aimed to evaluate the antimicrobial efficacy of photodynamic therapy (PDT) and light-activated disinfection (LAD) on zirconia dental implants contaminated with three bacterial species and investigate if the PDT and LAD cause implant surface alterations. METHODS Seventy-two zirconia dental implants were contaminated with a bacterial suspension of Prevotella intermedia, Actinomyces actinomycetemcomitans, and Porphyromonas gingivalis. The implants were subsequently randomly divided into four groups (n = 12 dental implants/each) according to the decontamination protocol: Group 1 (PDT1) - PDT (660 nm, 100 mW) with toluidine blue; Group 2 (PDT2) - PDT (660 nm, 100 mW) with phenothiazine chloride dye; Group 3 (LAD) - light emitting diode (LED) with toluidine blue; and Group 4 (TB) - toluidine blue without the application of light. Implants in the positive control (PC) group were treated with a 0.2% chlorhexidine-based solution, and implants assigned to the negative control (NC) group did not undergo any treatment. Each implant was then placed in tubes containing phosphate buffered saline (PBS) and vortexed for 60 s to remove the remaining bacteria from the implant surface. After 10-fold serial dilutions, 30 μl of the suspension was plated on Brucella agar plates. After 72 h, the colony forming units (CFU) were counted. Distinctive colonies were confirmed with MALDI Biotyper. The implants were analyzed using scanning electron microscope (SEM) to evaluate the possible surface alterations due to PDT or LAD. RESULTS All study groups had significant reductions in the number of CFUs compared with the NC (p < 0.05). PDT1, the PDT2, and the LAD groups had the largest bacterial reduction with respect to each bacterial species separately and the total bacterial count, and they were more efficient compared with the TB group (p < 0.05). SEM analysis did not reveal any alterations of the implant surface after the treatment procedures. CONCLUSION Both PDT protocols and LAD showed high and equal effectiveness in decontamination of zirconia dental implants.

Comparison of final disinfection protocols using antimicrobial photodynamic therapy and different irrigants after single-file reciprocating instrumentation against intracanal bacterial biofilm - an in vitro study

BACKGROUND The aim of the study was to compare the efficacy of antimicrobial photodynamic therapy (aPDT) with irrigation protocols that include sodium hypochlorite (NaOCl), ethylenediaminotetraacetic acid (EDTA) or QMiX (combined irrigant: EDTA, chlorhexidine, detergent) solution after single-file reciprocating root canal instrumentation. METHODS The study sample included 68 extracted mandibular human single canal teeth. The canals were inoculated with bacterial suspension made of wild strain of Enterococcus faecalis. After 17 days of incubation, the samples were assigned to experimental groups according to the final disinfection protocol and a control group. The root canals in all groups were, firstly, instrumented with Wave One Gold reciprocating system. Then the canals were disinfected as follows: Group 1. 2.5% NaOCl and EDTA followed by the application of the aPDT; Group 2. 2.5% NaOCl, EDTA and 2.5% NaOCl; Group 3. 2.5% NaOCl and QMIX solution; Group 4. 2.5% NaOCl and EDTA. In the control group, the canals were irrigated with saline solution. Microbiological samples were collected at baseline, after single-file instrumentation and after the final disinfection protocols. The samples were plated onto Mitis Salivarius agar plates for incubation. The colony forming units (CFUs) were counted, and the final number was determined based on the dilution factor. RESULTS Reciprocating single-file instrumentation reduced CFUs significantly in all groups (p<0.05). No significant difference between Group 1 and Group 2 was observed (p=0.178). Irrigation with the QMiX was more efficient than the aPDT (p=0.02). CONCLUSIONS The aPDT used after irrigation with NaOCl and EDTA demonstrated similar antimicrobial efficacy as conventional irrigation with NaOCl.

Effect of Different Laser Treatments on the Bond Strength of Intracanal Fiber Posts Cemented with a Self-Adhesive Resin Cement: Bond Strength of a Self-Adhesive Resin Cement

PURPOSE To evaluate the influence of laser-activated irrigation by Er:YAG and Er:YSGG (LAI) protocols and Nd:YAG laser irradiation on the bond strength of self-adhesively cemented fiber posts to root canal dentine. MATERIALS AND METHODS The study sample consisted of 84 human single-rooted permanent teeth instrumented with ProTaper Next technique. After obturation, post space preparations were created for fiber-reinforced composite posts. The prepared specimens were divided according to the laser treatment of the post space preparations: group 1: LAI (Er:YAG) + saline solution (pulse energy: 20 mJ, repetition rate: 15 Hz); group 2: LAI (Er:YAG) + QMiX solution (pulse energy: 20 mJ, repetition rate: 15 Hz); group 3: LAI (Er,Cr:YSGG) + saline solution (pulse energy: 62.5 mJ, 20 Hz); group 4: LAI (Er,Cr:YSGG) + QMiX (pulse energy: 62.5 mJ, 20 Hz); Nd:YAG laser (pulse energy: 100 mJ, 10 Hz). Fiber-reinforced posts were cemented with a self-adhesive cement. The bond strength was evaluated by the push-out bond strength test, and the mode of failure was determined under a stereomicroscope. Kruskal-Wallis test was used for the intergroup comparative analysis with 5% level of significance. RESULTS The highest bond strength was recorded in the Er:YAG + QMiX group (mean 3.401 MPa) (p < 0.05), followed by the Er,Cr:YSGG and the Er:YAG + saline solution (mean 1.111 MPa and 1.094 MPa, respectively), which did not differ significantly (p = 0.232). The irradiation with the Nd:YAG laser caused similar bond strength as the Er,Cr:YSGG + QMiX (p = 0.942). CONCLUSION All laser protocols enhanced the bond strength of the self-adhesive cement in root canals compared to only saline irrigation. The bond strength of the self-adhesive cement depended on the laser parameters and irrigant used for the LAI.

Antimicrobial Efficacy of Photodynamic Therapy and Light-Activated Disinfection Against Bacterial Species on Titanium Dental Implants

PURPOSE The aim of this study was to evaluate the efficacy of photodynamic therapy (PDT) and light-activated disinfection (LAD) against a 3-day-old bacterial suspension prepared from three different bacterial species present on titanium dental implants, and to analyze the possible alterations of the implant surfaces as a result of the PDT and LAD. MATERIALS AND METHODS The study was conducted on 72 titanium dental implants contaminated with a bacterial suspension prepared from three bacterial species: Prevotella intermedia, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis. The contaminated implants were incubated under anaerobic conditions for 72 hours and then were randomly divided into four experimental groups and two control groups (n = 12 each), according to the following treatment protocols: group 1 (PDT1): PDT (660 nm, 100 mW, 60 seconds) with toluidine blue; group 2 (PDT2): PDT (660 nm, 100 mW, 60 seconds) with phenothiazine chloride dye; group 3 (LAD): light-emitting diode (LED) with toluidine blue; group 4 (toluidine blue): treatment with only toluidine blue for 60 seconds. In the positive control group, the implants were treated with a 0.2% chlorhexidine-based solution for 60 seconds, and in the negative control group, no treatment was used. RESULTS The highest bacterial reduction was recorded in the PDT1 (98.3%) and PDT2 (97.8%) groups. The results of this study showed that there was a statistically significant reduction of bacteria in the PDT1 and PDT2 groups compared with the negative control group (P < .05), individually for each bacterial species as well as for all three species together. LAD was less effective than PDT1 and PDT2, and did not show a statistically significant difference compared with the negative control or any other treatment group. Toluidine blue was the least effective treatment in terms of both the total bacterial count and the individual count for each bacterial species. CONCLUSION Both PDT1 and PDT2 protocols showed a high efficacy against a 3-day-old bacterial biofilm on dental implants and were more effective compared with LAD.