Jean Paul Rocca

Patient responses to Er:YAG laser when used for conservative dentistry

The utilization of laser technology in conservative dentistry offers several advantages compared with traditional instruments, but one of the still unsolved problems is the difficulty in describing and explaining these advantages to patients. The aims of this study were to verify the efficacy of the way patients are informed and to evaluate their satisfaction with laser-assisted treatment. Before treatment, 100 patients were given a brochure that explained the relevant laser-assisted dental procedures, and after dental treatment an 11-item questionnaire was administered to the patients to evaluate their satisfaction with the treatment. Statistical analysis showed high levels of satisfaction for all the questions, especially those regarding the choice between laser therapy and traditional instruments (100%), choosing laser in the future (89%), and recommending it to family and friends (84%). This study may be relevant when determining the overall satisfaction of patients with this new technology.

Non-surgical periodontal therapy assisted by potassium-titanyl-phosphate laser: a pilot study.

As the American Academy of Periodontology indicates, the treatment of chronic periodontitis should be achieved in the least invasive manner through non-surgical periodontal therapy. However, complete removal of subgingival plaque and calculus is hindered with increasing probing depth (PD) and furcation involvement using hand, sonic or ultrasonic instruments. Many authors have suggested that the use of laser as an adjunct to scaling and root planing (SRP) might improve the effectiveness of conventional periodontal treatment. The aim of this study was to evaluate potassium–titanyl–phosphate (KTP) laser in non-surgical periodontal therapy. Seven hundred and thirty sites with probing depths of 4–6xa0mm were involved in the study. The sites were divided into four groups: control (SRP, chlorhexidine gel 0.5%), groupxa0A (SRP, chlorhexidine gel 0.5%, three sessions of KTP laser irradiation); groupxa0B (SRP, three sessions of KTP laser irradiation) and groupxa0C (SRP, irrigation with povidone-iodine 10%, three sessions of KTP laser irradiation). KTP laser was used with the following parameters: output power 0.6xa0W, time on 10xa0ms, time off 50xa0ms, 30xa0s per irradiation, fluence 19xa0J/cm2. All the sites showed improvement in all clinical parameters. Clinical attachment loss (CAL), pocket probing depths (PPDs) and bleeding on probing (BOP), especially in the lased groups, showed significant results (Pu2009<u20090.001). Our experience showed KTP laser to be a significant help in SRP; nevertheless, more studies are necessary to confirm our results.

Low energy KTP laser in oral soft tissues surgery: A 52 patients clinical study

Objectives: Since 1962 laser appliances have been used for soft tissues surgery of oral cavity with significant advantages compared to the traditional instruments: excellent bleeding control, possibility to avoid the use of suture, good patient compliance thanks to a decrease of intra- and post-operative discomfort and biostimulating effect. Unfortunately, the wavelengths so far used have been seen to cause, in association with an excellent ablation capacity, heat damage of the tissues that can decrease healing process and cause a greater discomfort to patients. The aim of this study was to evaluate the laser-assisted KTP laser surgery at low power in terms of characteristics of intervention and patients compliance. Study design: In this study, we describe the application of a new and recently introduced in dentistry wavelength, the KTP laser (532 nm), used with low power (1 Watt - CW), evaluating the time of interventions and, by a Numerical Rating Scale, the intra and postoperative pain. Results: KTP laser used at low power permits to obtain good pain control during operations that were carried out with only a topic anaesthetic (EMLA, Astratech), as shown in VAS tests. Good healing with limited or absent burning areas in treated portion of tissue. Conclusions: These preliminary study allows us to affirm that KTP laser with low parameters permits to perform oral surgery with good pain control and good wound healing. A greater number of clinical cases are however necessary to confirm the result obtained. Key words: Laser, KTP, oral surgery, thermal increase.

Thermal increase in the oral mucosa and in the jawbone during Nd:YAG laser applications. Ex vivo study.

Objective: Literature reports bactericidal and biostimulant effects for Nd:YAG laser procedures on bone and oral mucosa but the possible overheating can cause damage to anatomical structures. The aim of the study is the evaluation of thermal increase in different levels of oral tissues: mucosa, periosteum and bone during defocused application of Nd:YAG laser at different parameters. Study Design: Superficial thermal evaluation was performed in pig jaws with a thermal camera device; deep thermal evaluation was realized by 4 thermocouples placed at a subperiosteal level and at 1,2 and 4 mm depth in the jaw bone. Laser applications of 1 minute were performed 5 times (with a pause of 1 minute) on a surface of 4 cm2 with a Nd:YAG laser (VSP mode, 320 micrometer fiber, defocused mode) with different parameters. Temperatures were recorded before and after laser applications and after each pause in order to evaluate also the thermal relaxation of tissues. Results: At submucosal level, mean thermal increase was between 1.1°C and 13.2°C, at 1 mm depth between 1.1°C and 8.5°C, at 2 mm depth between 1.1°C and 6.8°C, at 4 mm depth between 1.0°C and 5.3°C. Temperature decrease during the rest time period was variable between 0°C and 2.5°C. Conclusions: Temperatures reached during clinical procedures with parameters reported in the literature in biostimulation protocols (1.25-2 Watts) for the five minutes of application are not dangerous for biological structures. The decrease in temperature during the rest time period is less considerable in the bone in comparison to oral mucosa. Key words:Nd:YAG laser, thermal increase, thermocouple, thermal camera, low level laser therapy.

Antimicrobial efficacy of photodynamic therapy, Nd:YAG laser and QMiX solution against Enterococcus faecalis biofilm

BACKGROUNDnLasers have been recommended in final root canal disinfection protocol, however, there is no clear evidence about their efficacy against bacteria in biofilms. The aim of the study was to evaluate and compare the disinfection effect of antimicrobial photodynamic therapy (aPDT), Nd:YAG laser and QMiX solution against Enterococcus faecalis biofilm.nnnMETHODSnThe study sample consisted of 65 dentine slices, which were inoculated with E. faecalis and incubated anaerobically for three weeks. The dentine discs were randomly allocated to one of the following experimental groups: aPDT (100 mW, 10 mg/ml phenothiazinium chloride, 1 min), Nd:YAG laser (2 W, 15 Hz, 4×5 s), QMiX solution (1 min). Positive controls did not receive any treatment and negative controls were treated with 5.25% NaOCl. To harvest surviving adherent cells, each dentine sample was transffered to a test tube containing of TSB, serial ten-fold dilutions were made and aliquot of 1 ml was plated onto blood agar plates and incubated for 48 h. Colony forming units grown were counted and transformed into actual counts based on the dilution factor. The remaining viable cells after each protocol were analysed by FISH.nnnRESULTSnThe aPDT and the QMiX solution were equally effective, with the reduction rate of E. faecalis CFUs of 98.8% and 99.3% respectively (p=1.107). The Nd:YAG laser caused 96% reduction of E. faecalis (P<0.001).nnnCONCLUSIONnThe aPDT and the QMiX solution showed similar antibacterial efficacy against old E. faecalis biofilm, followed by Nd:YAG irradiation.

Shear bond, wettability and AFM evaluations on CO2 laser-irradiated CAD/CAM ceramic surfaces

The purpose of this study is to determine the CO2 laser irradiation in comparison with sandblasting (Sb), hydrofluoric acid (Hf) and silane coupling agent (Si) on shear bond strength (SBS), roughness (Rg) and wettability (Wt) of resin cement to CAD/CAM ceramics. Sixty (CAD/CAM) ceramic discs were prepared and distributed into six different groups: group A, control lithium disilicate (Li); group B, control zirconia (Zr); group C, Li: CO2/HF/Si; group D, Li: HF/Si; group E, Zr: CO2/Sb/Si; group F, Zr: Sb/Si. Result showed significant difference between irradiated and non-irradiated in terms of shear bond strength for zirconia ceramics (p valueu2009=u20090.014). Moreover, partial surface wettability for irradiated and non-irradiated ceramics. Irradiated surface demonstrated more rough surface in lithium disilicate than zirconia ceramics. CO2 irradiation could increase shear bond strength, surface roughness and wettability for both CAD/CAM ceramics.

The effect of CO2 and Nd:YAP lasers on CAD/CAM Ceramics: SEM, EDS and thermal studies.

BACKGROUND AND AIMSnThe objective of this study was to investigate the interaction of infrared laser light on Computer Aided Design and Computer Aided Manufacturing (CAD/CAM) ceramic surfaces.nnnMATERIAL AND METHODSnSixty CAD/CAM ceramic discs were prepared and divided into two different groups: lithiumdisilicate ceramic (IPSe.maxCADs) and Zirconia ceramic (IPSe.maxZirCADs). The laser irradiation was performed on graphite and non-graphite surfaces with a Carbon Dioxide laser at 5W and 10W power in continuous mode (CW mode) and with Neodymium Yttrium Aluminum Perovskite (Nd:YAP) laser at 10W. Surface textures and compositions were examined using Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). Thermal elevation was measured by thermocouple during laser irradiation.nnnRESULTSnThe SEM observation showed a rough surface plus cracks and fissures on CO2 10W samples and melting areas in Nd:YAP samples; moreover, with CO2 5W smooth and shallow surfaces were observed. EDS analysis revealed that laser irradiation does not result in modifications of the chemical composition even if minor changes in the atomic mass percentage of the components were registered. Thermocouple showed several thermal changes during laser irradiation.nnnCONCLUSIONnCO2 and Nd:YAP lasers modify CAD/CAM ceramic surface without chemical composition modifications.

Co2 laser treatment of drug-induced gingival overgrowth - case report -.

Possibility, by several drugs, to produce, as collateral effect, gingival overgrowth, is largely described in literature 1,2) since 1939, when Kimball, reported for the first time the case of a hyperplasic modification in the gum of an epileptic patient treated with Dilantin. Actually, the agents causing gingival hyperplasia belong to three categories: anticonvulsivants (Phenytoin), immunosuppressant (Cyclosporine A) and calcium channel blockers for cardiovascular disease. 3) n nThe last belongs to the so called “calcium channel blockers” and its main action is to stop the passage of Ca++ ions through the membranes of the muscular cells of vessels and heart without modifying the haematic level of the calcium; in this way the contractile processes of the main arteries and coro-naries are inhibited. 4–6) n nGingival overgrowth normally appears within 13 months after the start of therapy, beginning from the interdental papilla; 7) clinical manifestation usually is similar with different type of drugs, even if some authors reported a more lobulated and hyperaemic gingival for patients treated with Cyclosporin A. 8) n nHistopathologic characteristics of gingival lesions are very similar independently from the drug assumed, and they consist in an excessive accumulation of extracellular matrix proteins (e.g. collagen) or amorphous ground substance, with a connective tissue response more implicated than epithelial cell layer involvement; 9) it is also always present a lym-pho-plasmocitary infiltrate, typical of chronic inflammation even when an acute flogosis, due to the bacterial plaque in the sulcular areas, is associated. 10,11) In these conditions, when the anamnestic investigation leads to the hypothesis of a relation between the agent assumed and the conditions of gums, it is mandatory to contact the specialist who prescribed the agent in order to substitute this drug with another, if possible. n nThe surgical therapy is not easy, due to the particular general clinical situation of these patients: 12) even if, in most important cases conventional intervention by scalpel must be done during hospitaliza-tion in order to have a control of bleeding because, in this kind of patient, risk is very high, 13,14) several authors proposed also the use of laser surgery in alternative to conventional intervention: less bleeding and pain, easier post-operative period, much less wound contraction and scarring are the advantages of this technique vs. scalpel. 15) n nUse of several different wavelengths to treat gingival overgrowth, such Argon, Nd:YAG, Diode, Er,Cr:YSGG, Er:YAG and CO2 has been reported in several works, 16–18) but in the case below described we decided to use Carbon Dioxide Laser, considering the importance of the lesion, the age of the patient and his general health conditions. 19) n nCO2 is a gas active medium laser which emits a beam of 10600 nm, in region of far infrared spectrum, with a great affinity for water and, even if it generally has a delivery system by articulated arm, it can also be distributed by hollow fibbers; the great advantage of this laser is that it can emit in C^W (Continuous Wave), in Pulsed Mode and also in Superpulsed Mode and this last way allows to control thermal elevation in target tissue. In this case we decided to utilise it in two modalities, superpulsed to make ablation and CW to produce coagulation in the tissue.

Er:YAG Laser: A New Technical Approach to Remove Torus Palatinus and Torus Mandibularis

Objective. The aim of this study was to assess the ability of Er:YAG laser to remove by excision torus mandibularis and to smooth torus palatinus exostosis. Materials and Methods. Torus mandibularis (TM) and torus palatinus (TP) were surgically eliminated via the Er:YAG laser using the following parameters: TM: output power ranging from 500 to 1000u2009mJ, frequency from 20 to 30u2009Hz, sapphire tips (diameter 0.8u2009mm), air-water spray (ratio 5/5), pulse duration 150u2009μsec, fluence ranging from 99592u2009J/cm2 to 199044,586u2009J/cm2. TP: a peeling technique was used to eliminate TP, as excision by slicing being impossible here. Results. TM: excision was obtained after 12730 pulses. TP: smoothing technique took more time compared with excision. Once peeling was considered to be accomplished, the use of a surgical rasp was necessary to eliminate bone spicules that could delay the wound to heal in good conditions. Conclusion. Er:YAG excision (TM) or Er:YAG peeling (TP) are safe clinical techniques easy to practice even if the time required for excision or surface smoothing is more than the time required with bony burs and high speed instruments.

Removal of calcified attached denticle with a pulsed dye laser: A case report

This article presents the removal of an attached pulp denticle with the use of a pulsed dye laser. The quartz fiber was introduced in the root canal and placed in direct contact with the free border of the denticle. Thirty-two pulses were necessary to fragment the pulp stone. A scanning electron-microscopic study shows a sharp section at the base of the pulp stone.