Cornelio Blus

Microbial biofilm modulation by ultrasound: Current concepts and controversies

Biofilm elimination is often necessary during antimicrobial therapy or industrial medical manufacturing decontamination. In this context, ultrasound treatment has been frequently described in the literature for its antibiofilm effectiveness, but at the same time, various authors have described ultrasound as a formidable enhancer of bacterial viability. This discrepancy has found no solution in the current literature for around 9 years; some works have shown that every time bacteria are exposed to an ultrasonic field, both destruction and stimulation phenomena co-exist. This co-existence proves to have different final effects based on various factors such as: ultrasound frequency and intensity, the bacterial species involved, the material used for ultrasound diffusion, the presence of cavitation effects and the forms of bacterial planktonic or biofilm. The aim of this work is to analyze current concepts regarding ultrasound effect on prokaryotic cells, and in particular ultrasound activity on bacterial biofilm.

Immediate Implants Placed in Infected and Noninfected Sites after Atraumatic Tooth Extraction and Placement with Ultrasonic Bone Surgery

BACKGROUND Only a few reports deal with implants placed in infected postextraction sites. PURPOSE Survival rates of a cohort of immediate implants cases placed in acute and chronically infected sites were compared with a cohort of noninfected ones while (1) tooth extraction and osteotomy sites were prepared with a piezosurgery device and (2) ultrasonication was applied to abate the bacterial charge at infected sites. MATERIALS AND METHODS Eighty-six patients received 168 immediate implants distributed into three groups: noninfected (85), acute (36), and chronically (47) infected sites. Atraumatic extraction and implant osteotomy were performed with an ultrasonic surgery device without flap elevation. All sites received the same medication and surgical protocol; infected sites were ultrasonicated during 30 seconds at 72 W. Kaplan-Meyer survival rates were calculated at 1 year. RESULTS The 1-year survival rates of the noninfected, chronically, and acute infected groups were 98.8, 100, and 94.4%, respectively. The differences were not statistically significant. No implant was lost after loading. All teeth and roots could be extracted in one piece. Drilling at extraction sockets was uncomplicated, without skidding. CONCLUSIONS Implant survival rates might be similar in infected and noninfected sites when infected sites receive standard medical and surgical treatment and are ultrasonicated. Atraumatic tooth/root extraction and implant placement can be reliably performed with piezoelectric surgery.

Use of Ultrasonic Bone Surgery (Piezosurgery) to Surgically Treat Bisphosphonate-Related Osteonecrosis of the Jaws (BRONJ). A Case Series Report with at Least 1 Year of Follow-Up

This preliminary work documents the use of a powerful piezosurgery device to treat biphosphonate-related osteonecrosis of the jaw (BRONJ) in combination with classical medication therapy. Eight patients presenting 9 BRONJ sites were treated, 2 in the maxilla and 7 in the mandible. Reason for biphosphonate (BiP) intake was treatment of an oncologic disease for 5 patients and osteoporosis for 3. The oncologic and osteoporosis patients were diagnosed with BRONJ after 35-110 months and 80-183 months of BiP treatment, respectively. BRONJ 2 and 3 was found in 4 patients. Resection of the bone sequestrae was performed with a high power ultrasonic (piezo) surgery and antibiotics were administrated for 2 weeks. Soft tissue healing was incomplete at the 2-week control but it was achieved within 1 month. At the 1-year control, soft tissue healing was maintained at all patients, without symptom recurrence. One patient with paraesthesia had abated; of the 2 pa-tients with trismus, one was healed, severity of the second trismus abated. This case report series suggests that bone resection performed with a high power ultrasonic surgery device combined with antibiotics might lead to BRONJ healing. More patients are warranted to confirm the present findings and assess this treatment approach.

Periodontal microbiota of Sardinian children: comparing 200-year-old samples to present-day ones

Introduction: The microrganisms of the human oral cavity include more than 700 species or phenotypes of bacteria. Some “diseases of civilization” are strictly correlated to changes in the microbiome following the food revolution that occurred after WWII. For that reason, a precise recognition of the microbiome profile before and after this period should be useful to determine the health-compatible model of microbiome. The aim of this study was to compare the microbiome profiles (number of total cells, and pathogen types) of dental samples obtained from two distinct groups of children, a 200-year-old retrieved one and a present one. Methods: Two different groups of samples have been studied. The first group was a set of 50 recent subgingival plaque samples obtained from children of age 2-8 years, 14 males and 36 females. They were enrolled by the Department of Dental Disease Prevention (University of Cagliari, in Sardinia, Italy) during standard dental care procedures. None reported periodontal disease and none had been under antibiotic therapy during the previous 6 months. The second group was an old retrieved group that included 24 teeth from 6 different 6- to 8-year-old crania fragments; they were obtained from a 200-year-old charnel-house located in Villaputzu, a city close to Cagliari. Representative periodontal bacteria have been identified by a previously published real-time PCR procedure (Sokransky et al., 1998) in which P. gingivalis and T. forsythia (red complex), A. actinomycetemcomitans (green complex) and F. nucleatum (orange complex) were detected. In addition, the title of each pathogen was expressed as a percentage of the total bacteria (biofilm) in the sample. Results and discussion: The profile of periodontal microbiomes, between recent/ancient samples showed a significant difference relative to Sokransky’s red complex bacteria (p < 0.05). In all analyzed periodontal strains, the pathogenic bacteria P. gingivalis and T. forsythia showed the highest title in the recent group. Conclusions: Our hypothesis is that the transfer of “commensal-pathogen” as an absolute number on the oral biofilm might be linked to the distinct alimentary habits of the two populations. Some diet rich in reducing agents, such as processed meat-based foods, might be able to increase the average number of pathogen anaerobic bacteria in the oral microbiota. The outcome would be an increase of the oral systemic diseases reported with these pathogens. Our data suggest that the ancient Sardinian population was able to control the pathogen oral anaerobic biofilm by some diet rich in antioxidant compounds. Further investigations are required to focus on the genetic profile and the health status of this ancient population but it appears that molecular microbiology might be considered as the “time machine” in oral biology.