Luigi Checchi

Vertical augmentation with interpositional blocks of anorganic bovine bone vs. 7-mm-long implants in posterior mandibles: 1-year results of a randomized clinical trial

OBJECTIVES To evaluate whether 7-mm-long implants could be an alternative to longer implants placed in vertically augmented posterior mandibles. MATERIALS AND METHODS Sixty patients with posterior mandibular edentulism with 7-8 mm bone height above the mandibular canal were randomized to either vertical augmentation with anorganic bovine bone blocks and delayed 5-month placement of ≥10 mm implants or to receive 7-mm-long implants. Four months after implant placement, provisional prostheses were delivered, replaced after 4 months, by definitive prostheses. The outcome measures were prosthesis and implant failures, any complications and peri-implant marginal bone levels. All patients were followed to 1 year after loading. RESULTS One patient dropped out from the short implant group. In two augmented mandibles, there was not sufficient bone to place 10-mm-long implants possibly because the blocks had broken apart during insertion. One prosthesis could not be placed when planned in the 7 mm group vs. three prostheses in the augmented group, because of early failure of one implant in each patient. Four complications (wound dehiscence) occurred during graft healing in the augmented group vs. none in the 7 mm group. No complications occurred after implant placement. These differences were not statistically significant. One year after loading, patients of both groups lost an average of 1 mm of peri-implant bone. There no statistically significant differences in bone loss between groups. CONCLUSIONS When residual bone height over the mandibular canal is between 7 and 8 mm, 7 mm short implants might be a preferable choice than vertical augmentation, reducing the chair time, expenses and morbidity. These 1-year preliminary results need to be confirmed by follow-up of at least 5 years.

Efficacy of three face masks in preventing inhalation of airborne contaminants in dental practice.

ABSTRACT Background Up-to-date studies are needed on the protection provided by face masks used by dentists. We assessed the relative filtering efficacy of two currently used surgical face masks (one a molded mask, the other a tie-on mask) and a certified personal particulate respirator, all made by a single manufacturer. Methods The authors sprayed bicarbonate particulate against a porcelain surface (representing the patients mouth) and collected it via a mannequin head (representing the dentists head) placed 40 centimeters away and a tube with two airflow rates (0.5 cubic meters per hour and 9 m3/hour). They calculated the dry residue weight. They performed three separate runs for each mask and three runs with no mask at the two airflow rates with and without aerosol. Results With no mask (control), the authors recorded significant weight gains at both airflow rates with and without vaporization. With vaporization, the three masks were associated with different dry residue weights (P < .03 with the Kruskal-Wallis test at both flow rates), the respirator providing the lowest amount. The respirator provided an efficiency of 94 to 96 percent, compared with 90 to 92 percent and 85 to 86 percent for the molded and tie-on surgical masks, respectively. Conclusions These data provide independent evidence that a certified personal respirator can be more effective than high-quality surgical masks in dental settings. Clinical Implications Dentists should be aware that a certified particulate respirator can provide them with superior filtering protection.

Clinical-radiographic and histological evaluation of two hydroxyapatites in human extraction sockets: a pilot study

After tooth extraction the healing process involves bone resorption and soft tissue contraction, events that can compromise the ideal implant placement with functional and aesthetic limitations. Following tooth extraction, a socket preservation technique can limit bone resorption. This study evaluated two different types of hydroxyapatite (HA) grafting materials placed into fresh extraction sockets, 6 months after tooth extraction, histologically, clinically and radiographically. Ten extraction sockets from 10 patients were divided in two groups: 5 sockets received a biomimetic HA and 5 received nanocrystalline HA. After 6 months, before implant placement, samples from the grafted area were harvested and evaluated clinically, radiographically and histologically. The percentages of bone, osteoid areas and residual material in the two groups were not statistically different. All samples showed great variability with extensive bone formation and total material resorption or amounts of osteoid tissue that filled the spaces between the residual material particles. The authors did not find any differences between biomimetic and nanocrystalline HA and assume that, within the limits of this study, both these materials could be applied into fresh extraction sockets to limit bone resorption. A control material and a much larger sample size are needed to confirm these findings.

The Relationship Between Bleeding on Probing and Subgingival Deposits. An Endoscopical Evaluation

Background: Bleeding on probing (BOP) is an indicator of tissue inflammatory response to bacterial pathogens. Due to anatomical limitations, the entity and physical state of microbial aggregations located under the gingival margin and their relations to BOP have been hardly investigated till now. The recent introduction of the endoscopy has allowed clinicians to observe the subgingival environment in a non-traumatic way. The aim of this study is to evaluate the correlation between BOP and subgingival deposits by using this new technology. Methods: 107 teeth (642 individual sites) from 16 periodontal patients, treated with scaling and root planing, were evaluated for plaque index (PI), gingival index (GI), probing pocket depth (PPD), bleeding on probing (BOP), endoscopic biofilm index (EBI), and endoscopic calculus index (ECI) at one-month revaluation. Results: A linear association between BOP and PD, EBI, and ECI was detected. The BOP provided a high level of specificity but quite low sensitivity values both for ECI (sensitivity 40%, specificity 86%) and EBI (sensitivity 37%, specificity 89%). The BOP sensitivity was directly linked to the amount of subgingival deposits. Conclusions: This study demonstrates a direct relationship between BOP and presence/amount of subgingival deposits. More investigations on larger samples are, however, needed.

EXPERIMENTAL ANALYSIS OF TENSILE PROPERTIES OF SOME SUTURING MATERIALS

The aim of the investigation is to quantitatively evaluate the failure load of several suture materials currently used in dentistry surgery. No chromic catgut, silk, Prolene, Ethilon, Ethibond, Vicryl and Vicryl Rapid, obtained from Ethicon s.p.a., in the sizes 3–0, 4–0, and 5–0 have been tested. The analysis has been carried out measuring the diameter of each suture with an optical microscope to determine the accuracy of manufacturers’ data. Tensile testing has been performed to evaluate the failure load of each material. Finally, sutures of the same effective diameter class have been compared relative to failure load. Results show that monofilament sutures present a failure load remarkably superior to that of multifilament sutures. Using SEM analysis monofilament sutures present less surface irregularities than multifilament sutures. Only monofilaments Ethilon 4–0 and 5–0, Prolene 4–0, and multifilament no chromic catgut 4–0 and 5–0 meet the requirements of the Italian Pharmacopeia. In contrast, Prolene 5–0 and the other multifilaments, silk, Ethibond, Vicryl and Vicryl rapid, have a larger diameter than that declared on the label by the producer.

A latex membrane, as an alternative device in the GTR technique: preliminary report on its biocompatibility

Polymeric materials are of widespread use for many clinical applications, including dentistry. Periodontal guided tissue regeneration (GTR) is a technique developed to treat periodontal disease: it implies that new connective tissue attachment and bone regeneration are achieved, whereas epithelial migration is prevented by the placement of a barrier membrane. This study has focused on the toxicity in vitro of different polymeric membranes, either commercial or experimental, with a latex rubber membrane being of special interest for use as an implant material in guided tissue regeneration in periodontology. A cell culture system tested by quantitative assay methods offered a reliable tool which provided meaningful results on the first level biocompatibility of such membranes.

Photobiomodulation with low-level diode laser promotes osteoblast migration in an in vitro micro wound model

Abstract. Laser photobiomodulation can improve bone healing, but well-defined treatment parameters are lacking. Saos-2 human osteoblast-like cells were subjected to an in vitro scratch-wound healing assay and irradiated by a 915-nm gallium-aluminum-arsenide diode laser for 0, 48, 96, and 144 s using doses of, respectively, 0, 5, 10, and 15  J/cm2. Wound area was measured after 4, 24, 48, and 72 h. Cell viability, DNA content, gene expression, and release of bone-related proteins were evaluated after 24, 48, and 72 h. Laser significantly improved wound healing compared with nonirradiated controls. Cells treated with laser doses of 5 and 10  J/cm2 reached wound closure after 72 h, followed by 15  J/cm2 after 96 h. With the cell proliferation inhibitor Mitomycin C, the doses of 10 and 15  J/cm2 maintained an improved wound healing compared with controls. Laser increased collagen type 1 gene expression with higher doses inducing a longer-lasting effect, whereas transforming growth factor-beta 1 showed comparable or decreased levels in irradiated versus nonirradiated groups, with no effect on protein release. This study demonstrated that laser photobiomodulation at 915 nm promoted wound healing mainly through stimulation of cell migration and collagen deposition by osteoblasts.

Different doses of low-level laser irradiation modulate the in vitro response of osteoblast-like cells

Abstract. Because osteoblasts play a key role in bone remodeling and the influence of low-level laser therapy on this process is not clear, Saos-2 human osteoblast-like cells were irradiated by a gallium–aluminum–arsenide diode laser (915 nm) for 10, 48, 96, 193, and 482 s using doses 1, 5, 10, 20, and 50  J/cm2, respectively. A control group was not irradiated. Morphology, viability, and cytotoxicity analyses were carried out after 1 hr, 1 day, and 3 days. Deoxyribose nucleic acid (DNA) content and release of vascular endothelial growth factor (VEGF), receptor activator of nuclear factor kappa B ligand (RANKL), and osteoprotegerin (OPG) were evaluated. Viability was modulated by laser irradiation in a dose-dependent manner, with 10  J/cm2 inducing a biostimulatory response and 20 to 50  J/cm2 determining a bioinhibitory and cytotoxic effect. Accordingly, DNA content was generally increased for the 10  J/cm2 dose and decreased for the 50  J/cm2 dose. A rapid and transitory trend toward increased RANKL/OPG ratio and a tendency toward a delayed increase in VEGF release for doses of 1 to 10  J/cm2 was found. Further investigations using the biostimulatory dose of 10  J/cm2 emerged from this study are needed to establish the ideal treatment regimens in the laboratory as well as in clinical practice.

Absence of Helicobacter pylori in dental plaque assessed by stool test.

TO THE EDITOR: Helicobacter pylori (H. pylori) is a human pathogen that causes chronic gastritis, predisposes to gastric and duodenal ulcer, and has been recognized as a group I gastric carcinogen (1). It represents the second most common bacterial infection throughout the world (second only to periodontitis), involving 40–50% of the population in developed countries and up to 80–90% of the population in the developing ones (2). Knowledge about the transmission of the bacterium is still incomplete. However, it remains unclear whether the transmission occurs mainly via the fecal–oral route rather than the oral–oral route. Up to now there are two widely available noninvasive methods to detect H. pylori infection: 13C or 14C labeled urea breath test (UBT), which are based on the detection of 13C or 14C labeled CO2 in expired air as a result of H. pylori urease activity (3), and serology (based on the detection of a specific anti-H. pylori immune response, mostly by IgG, in patients serum (2).

Occupational Exposure to Blood and Body Fluids in a Department of Oral Sciences: Results of a Thirteen-Year Surveillance Study

Objectives. Aim of this analysis was to identify trends that will aid in the prevention of injury. Methods. Our data were collected from 1999 to 2011 during a surveillance program of occupational exposures to blood or other potentially infectious materials in a Dental School by using a standard coded protocol. Results. 63 exposures were reported. 56/63 (89%) percutaneous and 7/63 (11%) mucosal, involving a splash to the eye of the dental care workers (DCW). 25/63 (40%) involved students, 23/63 (36%) DCW attending masters and doctorate, 13/63 (21%) DCW attending as tutors and 2/63 (3%) staff. 45/63 (71%) and 18/63 (29%) occurred respectively during and after the use of the device; of last ones, 1/18 (0.05%) were related to instrument clean-up and 1/18 (0.05%) to laboratory activity, 12/18 (67%) occurred when a DCW collided with a sharp object during the setting, and 4/18 (22%) during other activities. The instrument and the body part most likely involved were needle and finger respectively. The overall exposure rate was 4.78 per 10,000 patient visits. Conclusions Our results may serve as benchmark that Dental Schools can employ to assess their frequency of injury.