Jacek Matys

Thermodynamic effects after Diode and Er:YAG laser irradiation of grade IV and V titanium implants placed in bone - an ex vivo study. Preliminary report.

Abstract Many inserted implants are affected by peri-implantitis. The aim of our study was to evaluate increases in implant temperature, depending on the diameter and chemical composition of implants. In particular we measured the time it takes for the temperature of an implant to rise by 10°C and evaluated laser power settings required to prevent thermal injury when an implant surface is decontaminated during the treatment of peri-implantitis. The study analysed six implants placed in porcine ribs and divided into two groups according to their diameter and chemical composition (grade IV and grade V titanium). The implants were irradiated with Diode and Er:YAG lasers using different laser parameters. The temperature was measured with a K-type thermocouple. The temperature on the implant surface rose as the laser power increased and the implant diameter decreased. The time required to increase the temperature of an implant by 10°C was less than it was for titanium grade IV. The temperature gradient was below 10°C for all implants treated using a laser power up to 1 W. It is important to choose the correct laser parameters, depending on the chemical composition and diameter of the implant, so that decontamination of the implant surface is thorough, effective and safe.

Schneiderian Membrane Perforation Rate and Increase in Bone Temperature During Maxillary Sinus Floor Elevation by Means of Er: YAG Laser—An Animal Study in Pigs

Purpose: To assess the time of preparation, bone temperature increase, and the Schneiderian membrane perforation rate during maxillary sinus floor elevation. Materials and Methods: The research included 30 maxillary sinuses (n = 30) of a pig, divided into 2 groups (n = 15). The lateral bony windows were created using Er:YAG laser (200 mJ, 15 Hz, energy density: 25.48 J/cm2) and a diamond bur (control). The membrane was elevated using laser (50 mJ, 50 Hz) and hand instruments. The bone temperature was measured by K-type thermocouple. Results: Significantly lower rates of the Schneiderian membrane perforation were found in the laser group (6.67%) compared with the bur (33%) (P < 0.05). The significant higher increase in temperature (mean 7.6°C) was found in the experimental group as compared with the control group (mean 2°C) (P = 0.0000033). The average time necessary for the laser bony window osteotomy was 10 minutes and 37 seconds, whereas using the bur required middling 5 minutes and 50 seconds (P = 0.000283). Conclusion: The application of Er:YAG laser may significantly reduce the risk of iatrogenic perforation of the Schneiderian membrane and does not cause an irreversible thermal damage in a pig model.

Assessment of Temperature Rise and Time of Alveolar Ridge Splitting by Means of Er:YAG Laser, Piezosurgery, and Surgical Saw: An Ex Vivo Study

The most common adverse effect after bone cutting is a thermal damage. The aim of our study was to evaluate the bone temperature rise during an alveolar ridge splitting, rating the time needed to perform this procedure and the time to raise the temperature of a bone by 10°C, as well as to evaluate the bone carbonization occurrence. The research included 60 mandibles (n = 60) of adult pigs, divided into 4 groups (n = 15). Two vertical and one horizontal cut have been done in an alveolar ridge using Er:YAG laser with set power of 200 mJ (G1), 400 mJ (G2), piezosurgery unit (G3), and a saw (G4). The temperature was measured by K-type thermocouple. The highest temperature gradient was noted for piezosurgery on the buccal and lingual side of mandible. The temperature rises on the bone surface along with the increase of laser power. The lower time needed to perform ridge splitting was measured for a saw, piezosurgery, and Er:YAG laser with power of 400 mJ and 200 mJ, respectively. The temperature rise measured on the bone over 10°C and bone carbonization occurrence was not reported in all study groups. Piezosurgery, Er:YAG laser (200 mJ and 400 mJ), and surgical saw are useful and safe tools in ridge splitting surgery.

Complete dentures for a patient after a stroke by means of orofacial myofunctional therapy: A clinical report

After a stroke, patients frequently show compromised swallowing, mastication, and speech, as well as unfavorable motion and deviation of the tongue and mandible. The dentist can improve the oral rehabilitation of a patient with deteriorated facial and oral muscles after a stroke by incorporating orofacial myofunctional therapy. This report describes a method for tongue exercises and correction of mandible deviation in an edentulous patient after a stroke by using a pearl on a wire in the anteriomedian palatal part of the maxillary denture.

Comparison of the clinical and microbiological effectsofantibiotic therapy in periodontal pockets following laser treatment:An in vivo study

BACKGROUND Laser technology in periodontal therapy could help in reducing total bacterial count. OBJECTIVES The aim of this study was to evaluate the effects of pocket debridement using an erbium-doped yttrium aluminium garnet laser (Er:YAG laser - ERL), scaling and root planing (SRP) with photodynamic therapy (PDT), or SRP alone. Teeth vitality and soft tissue carbonization were also assessed. MATERIAL AND METHODS This study included 1,169 single-rooted teeth from 84 patients divided into 3 groups (n = 28). The G1 group had ERL with 40 mJ of energy, a frequency of 40 Hz and a fluence of 63.66 J/cm2. The G2 group had SRP + PDT (635 nm diode laser, 12 J of energy and irradiation time of 30 s) and a Toluidine Blue photosensitizer (PS) (application time of 60 s). The G3 group was administered SRP alone. In the 42 subjects (G1: n = 11, G2: n = 14 and G3: n = 17) with high amounts of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Treponema denticola (Td) and Tannerella forsythia (Tf), additional 1-week antibiotic treatments with clindamycin or amoxicillin + clavulanic acid - in doses of 600 mg/day or 1000 mg/day, respectively - were prescribed 3 months after the therapy. Microbiological and clinical analyses of the probing depth (PD), recession (RC), plaque index (PI), bleeding on probing (BOP), and attachment loss (AT) were performed at baseline and at the follow-up of 3 months, 3 months and 1 week, and 6 months. RESULTS Plaque index decreased in G1 after 3 months, 3 months and 1 week, and 6 months (p < 0.05) and was lower in G1 vs G2 after 3 months (p < 0.05). The reduction in BOP in G1 after 3 months and 1 week was higher in comparison with G2 or G3 (p < 0.02). Probing depth decreased in all groups (p < 0.05). We found a reduction in the percentage of sites with some bacteria after 3 months - Prevotella intermedia (Pi) (G1 and G2), Capnocytophaga gingivalis (Cg) and Eubacterium nucleatum (En) (G3), and after 3 months and 1 week with En, Td, Tf (G1, G2 and G3), Pi (G1 and G2), Aa, Peptostreptococcus micros (Pm), and Cg (G3), and with Pi (G1 and G2), Tf (G2), Pg, En (G2 and G3), and Pm (G3) after 6 months (p < 0.05). We observed no signs of carbonization or teeth injury. CONCLUSIONS Scaling and root planing + PDT and ERL may be an alternative therapy for chronic periodontitis.

Assessment of the primary stability of root analog zirconia implants designed using cone beam computed tomography software by means of the Periotest® device: An ex vivo study. A preliminary report

BACKGROUND The implant primary stability is a fundamental prerequisite for a success of osseointegration process which determines the prosthetic reconstruction time. OBJECTIVES The aim of the present study was to assess the quality and precision of modern conical bone computer tomography (CBCT) software in preparing root analog zirconia implants (RAZIs) by measuring its primary stability by means of the Periotest device. MATERIAL AND METHODS Thirteen pig jaws with proper erupted first premolar (P1) teeth were used in the study. The CBCT examination was conducted in the area of the P1 tooth in each mandible. The 3-dimensional (3D) view of each tooth was designed from CBCT scan. The created 3D images were used to prepare root analog zirconia implants milled from a medical-grade zirconia block by means of laboratory milling. The RAZIs and titanium implants were placed into an alveolar socket after the tooth had been removed. The primary stability of the teeth before their extraction (G1), RAZIs (G2) and titanium implants (G3) were checked by Periotest devices. RESULTS The mean results in PTV were: 15.9, 3.35, 12.7 for G1, G2 and G3 group, respectively. RAZIs during immediate loading achieved a significantly higher primary stability (lower Periotest value) as compared to the teeth and implants. CONCLUSIONS The modern CBCT device allows us to design a precise image of an extracted tooth for the purpose of manufacturing a root analog implant. The additional feature of the surgical protocol using RAZI is the possibility of avoiding the augmentation procedure, which reduces the whole cost of the treatment.

Effect of diode lasers with wavelength of 445 and 980 nm on a temperature rise when uncovering implants for second stage surgery: An ex-vivo study in pigs

BACKGROUND Many surgical procedures in soft tissue are performed using diode lasers. Recently, a novel diode laser operating at 445 nm wavelength was introduced in dentistry. OBJECTIVES The aim of our study was to evaluate the time of surgery and an increase in temperature of titanium implants during its uncovering using 445 and 980 nm wavelengths. MATERIAL AND METHODS The research included 45 pig mandibles (n = 45). The specimens were randomly divided into 3 groups (n = 15) according to the laser irradiation mode and wavelength; G1 - 445 nm laser, power: 3 W, continuous wave (CW), distance: 2 mm, power density: 7460 W/cm2, fiber: 320 μm, noncontact mode; G2 - 445 nm laser (power: 2 W, CW, power density: 4970 W/cm2, fiber: 320 μm, contact mode; G3 (control) - 980 nm laser, power: 2.5 W, CW, power density: 15920 W/cm2, fiber: 200 μm, contact mode. The temperature was measured with a 2 K-type thermocouples (a P1 at collar and a P2 at mid height of the implant). RESULTS The mean temperature rises measured by the P1 thermocouple were 16.9°C, 36.1°C and 21.6°C in the G1, G2 and G3 group, respectively. Significant differences in temperature rise were found between the G1 and G2 group (p = 0.0007) and the G2 and G3 group (p = 0.01). The mean temperature rises measured by the P2 thermocouple were 1.8°C, 1.4°C and 5.6°C in the G1, G2 and G3 group, respectively. Significant differences in temperature rise were found between the G1 and the G2 or G3 group (p = 0.0001). The significant differences among the study groups in average time necessary for uncovering the implants amounted to 69.7, 54.4 and 83.6 s, respectively (p < 0.05). CONCLUSIONS The application of the 445 nm diode laser in non-contact mode reduced the temperature rise of the implants. The additional pulse intervals during laser irradiation with wavelength of 445 nm when operating in contact mode are needed.

Assessment of Pain When Uncovering Implants with Er:YAG Laser or Scalpel for Second Stage Surgery

BACKGROUND Different methods aimed at decreasing pain during some soft tissue procedures in dentistry are still under research. Modern devices as lasers could be a method to reduce the pain and duration of second stage implant surgery. OBJECTIVES To assess the pain and the impression quality when uncovering implants with a laser and with a scalpel. MATERIAL AND METHODS The analysis included 60 implants (Dentium SuperLine, Suwon, Korea) in 30 patients (23 women and 7 men) aged 25-69. In the experimental group, 30 implants were uncovered by means of an Er:YAG laser (LiteTouch®, Syneron Dental, Yokneam, Israel) with the following fixed operation parameters: 300 mJ, 18 Hz, water cooling at 40%, energy density per pulse: 38.21 J/cm2, tip size: 1.0 × 17 mm, distance: 2 mm, tip angle set at 70°, no anesthesia. As a control, 30 implants were uncovered using a scalpel and topical application of 20% benzocaine. An 11-point numeric pain rating scale (NRS-11) was used to evaluate the pain level. A 3-point prosthetic impression scale (PIS) designed by the authors was used to assess the quality of the impression of the implant emergence profile. RESULTS The mean value of pain assessed on the NRS-11 for the Er:YAG laser and scalpel were 2.6 and 6, respectively. The mean value of pain for the laser and scalpel at a supracrestal height of periimplant soft tissue (SHPST) ≤ 3 mm were 1.8 and 4.7 respectively, and for SHPST > 3 mm the values were 3.3 and 7.4, respectively. The implant emergence profile impression showed satisfactory or ideal quality in 26 cases. CONCLUSIONS The use of Er:YAG laser reduces pain and allows minor surgical procedures to be carried out without anesthesia. The impression quality is satisfactory for the preparation of prosthetic reconstructions.

Energy and Power Density: A Key Factor in Lasers Studies

To the editor I read with interest, three articles in subject of laser studies published in JCDR in last few months. The authors in their researches used different types of lasers devices: Niranjani et al., (diode laser), Murthy et al., (CO2 laser), Kanumuru and Subbaiah (diode and Nd:YAG lasers) [1–3]. Unfortunately the authors have not presented in their researches a value of energy density (fluency) of lasers which is key factor to measure a dose of energy absorbed by treated tissues [Table/Fig-1]. [Table/Fig-1]: Comparison of studies Different types of lasers with same or different wavelength have been utilized in medical market, but the varied inbuilt technology in these devices provides divergent results in energy density (amount of light) which is absorbed by the tissue. The total energy delivered, divided by the area (energy per unit area) is called fluency or energy density. In a number of examples, fluency is the most important parameter for laser therapy [4]. Aside from energy density, a second important parameter in lasers measurement is a power density. The power density (irradiance) is a ratio of power (P) in Watt (W) to the cross section area (I=W/cm2). The importance of this will be clarified when we consider the interaction of laser beams with different materials [5]. Example: A pulsed laser emitting a beam with repetition rate f =1 pulse per second (1Hz), with energy of 50mJ (0.05J), for two diameters of a laser tip, the results in fluency (J/cm2) are divergent: 200μm tip, E=J/πr2, r=0.5d, r=0.01cm; 0.05J/3.14*0.012= 159.2J/cm2 per pulse 400 μm tip, E=J/πr2, r=0.5d, r=0.02cm; 0.05J/3.14*0.012= 39.8J/cm2 per pulse As the example showed that doubling of tip diameter implicates in 4 times energy density growth. It is very important in all studies that a data which can help to repeat each experiment by other researchers should be provided. Thus, all the studies should include the important parameters which allow comparing different kinds of lasers [4]. In Niranjani et al., Murthy et al., and Kanumuru and Subbaiah studies it is not possible to calculate and compare energy or power density [1–3]. In the author’s opinion, it is important that researchers and clinicians using lasers be educated in laser science. Without doubt, the principal knowledge of laser physics is unquestionably important to utilize lasers in good and safe manner.

Shear Bond Strength - New Reports.

To The Editor, I read with interest, the article by Kakodkar et al., [1] published in the May 2012 issue of Journal of Clinical and Diagnostic Research, titled “Lasers in Conservative Dentistry: An Overview ” The authors made a review of lasers using in conservative dentistry. The key factor for preparing highly adhesive surface in an enamel and a dentin by use of Er:YAG lasers are: type of laser (Gaussian distribution of energy), short laser pulses duration, low power of laser beam, fluid pumping technology (fluid pressure), time of emission of a laser beam, type of laser tip [2]. Er: YAG laser without optic fibre and with rectangular energy distribution profile, generate high power, uniform as regards the beam and with low energy losses during transport. In most of the presently used lasers, the energy beam is transported to the tip by means of an optic fibre, which distorts the energy distribution. In such lasers, the highest energy is located only in the middle of the beam and it is much lower at the edges. Concentration of the beam power in the very centre (older technology) with relatively low power and high frequency settings may cause thermal damage in the hard tissue [2]. A new laser technology result in reductions of Er: YAG laser defects; for example: overheating of the tooth, melting of hydroxyapatite and lower adhesion of dental materials to a tooth [2,3]. As authors pointed out, the adhesion of the dental hard tissue after an Er:YAG laser etching is inferior to that which is obtained after 37% phosphoric acid etching. However, a laser technology is still developing and recently new research shows different results of shear bond strength (SBS) of enamel and dentin etched by laser. Sagir et al., shows that the mean SBS values of laser-etched group was significantly higher (p<0.01) than the acid-etched group for enamel [4]. Frank et al., shows that additional laser conditioning after phosphoric acid etch is beneficial to one generation of bonding resin [5].