Conventional Handpiece Research Articles

Опыт клинического применения активной ультразвуковой рукоятки со встроенным датчиком давления

Purpose: Clinical testing of new ultrasonic handpiece with active transducer of pressure Active Sentry (AS), optional for phacomachine Cebturion. The study is based on the analysis of surgical records and disease histories of 100 patients operated on age-related cataract, by the method of ultrasonic phacoemulsification. All surgeries were performed by one surgeon by using the phacomachine Cebturion with settings ensuring safety and efficacy of the procedure. The half of all procedures were performed using the conventional ultrasonic handpiece (OZ), and the other half – using the handpiece with active transducer of pressure (AS). The evaluation criteria used include the following: pressure level of irrigating fluid used for nucleofragmentation; nucleofragmentation time; percentage loss of the posterior corneal epithelium cells. Results. With equal safety of the procedure, using the ultrasonic handpiece with active transducer of pressure (AS) in the course of nucleofragmentation enables the reduction of irrigating fluid pressure (BSS) by 20 mm Hg, followed by the reduction of BBS volume passing through the anterior chamber by 30 ml upon the average. The rate of the intraoperative endothelial cells loss when using the ultrasonic active handpiece is also lower, as compared to the conventional one, 8.3±3.2 vs 10.2±2.1, respectively. However this difference could not be confirmed by statistical data, possibly due to the limited sample of patients. Conclusions. The introduction of a new active ultrasonic handpiece (AS) for phacomachine Cebturion allows further reduction of procedural injury, while maintaining high efficiency of nucleofragmentation. Key words: рhacoemulsification of cataract, ultrasonic handle, active transducer of ocular pressure, reducing of surgical injury.

Use of auxiliary devices during retreatment of direct resin composite veneers.

The removal of direct composite veneers, when the retreatment is necessary, represents a challenge to the clinician, since the healthy dental structure must be preserved. Thus, the aim of this study was to compare the accuracy provided by different auxiliary devices during retreatment of direct composite veneers. Seventy-five bovine teeth were prepared for direct composite veneers, scanned (T1), and restored. Specimens were divided into 5 groups for retreatment: conventional high-speed handpiece without auxiliary device (WD); high-speed handpiece with a white LED (WL); high-speed handpiece with an UV light (UL); electric motor and multiplier 1/5 handpiece (EM); and conventional high-speed handpiece using magnifying loupe (ML). After retreatments, other scanning was performed (T2). Changes on dental wear or composite residues areas, as well as, the average between wear and presence of residues were measured. Data were submitted to Kruskal-Wallis and Dunn’s post-test (p≤ 0.05). There were greater areas of wear for ML, being statistically superior to WD and EM groups. The ML presented smaller residues areas, being statistically lower than the WD and EM groups. Regarding the average between wear and the presence of resin residues, additional wear occurred after re-preparation, regardless of the group. Magnifying loupe promoted greater areas of wear and smaller areas of resin residues than conventional high-speed handpiece and electric motor. Both techniques using light accessories did not differ from other ones.

A Comparative Study to Evaluate the Surface Quality of Erbium Dental Lasers with Conventional Bur Preparation Followed by the Microleakage Assessment of the Composite and Cerec Cad-Cam Restored Cavities

The surface quality of the prepared tooth strongly contributes to the longevity of the filling material and protection against caries. Restoration failure and development of incipient caries under the restoration are one of the major problems we face in our old dental practice despite our utmost struggle. This problem was never addressed until the introduction of modern technology that revealed the mystery behind the failure. With the new modern laser technology, we can overcome the problem at ease. Dental hard tissue laser prepares the cavities through the process called “Water Mediated Ablation”. It has the advantages over the conventional bur preparation by removing any debris such as smear layer and bacterial colonies within the dentinal tubules. This paper therefore, is a comparative study that examines the surface quality of the teeth cavities prepared with two high-end dental lasers Er: YAG, Er, Cr: YSGG with the conventional handpiece bur. Same settings were used for both hard tissue Er: YAG and Er, Cr: YSGG lasers. The surface quality of prepared cavities was examined under an electron microscope. Restoration is made using the state of the art CEREC Cad-Cam system and conventional nano-composite filling material. Cavities were scored for microleakage after thermocycling and dye penetration test. This penetration test contributes to nearly 10 years of stress in the normal oral environment. The microleakage was then examined under a leica microscope. The surface quality of the cavities prepared with both dental hard tissue lasers was clear of smear layer promising the longevity and durability of the restoration and declining of incipient caries. Convention preparation showed smear layer and obstruction of dentinal tubules preventing the bonding material to penetrate and seal leading to the future development of incipient caries and dislodgements.

Randomized clinical study comparing Piezoelectric Surgery with conventional rotatory osteotomy in mandibular third molars surgeries

PurposeThe aim of this study was to evaluate the performance and to assess the postoperative sequel and quality of life after removal of impacted mandibular third molars using piezoelectric surgery compared with conventional rotatory osteotomy. Patients and methodsA single blinded, randomized, control clinical study was performed. Sixty-three patients (44 males, 19 females) who presented with bilaterally asymptomatic impacted mandibular third molars were included in this analysis. Each patient was treated, at two separate sessions approximately 4 weeks apart, with a conventional rotatory hand piece on one side of the mandible and a piezoelectric device on the contralateral side. Patients were followed up on postoperative days 1, 3, 5, 7, and 15 to rate the pain, swelling and trismus. Inferior alveolar nerve paresthesia was evaluated up to 12 months postoperatively. ResultsThe severity of the pain, trismus and swelling using the piezosurgery were significantly different from the rotary group. In both groups, pain was most intense and peaked during the first post-operative day, while swelling and trismus reached peak levels on the third postoperative day. The piezoelectric procedure resulted in a significantly longer procedural duration compared to the rotatory surgery (P < 0.001). ConclusionPiezoelectric surgery is considered a viable alternative technique compared to the conventional rotary systems and can improve a patient’s quality of life. Thus, piezoelectric surgery might be a preferred modality for patients undergoing complicated surgical extraction of impacted lower third molars.

Comparison of a piezoelectric and a standard surgical handpiece in third molar surgery

AbstractAimThe aim was to compare the use of a piezoelectric handpiece versus a standard surgical handpiece in removal of impacted third molars under general anaesthesia.Materials and methodsThirty patients undergoing routine third molar removal were included in the study. Panoramic radiographs were used to assess the positioning of the impacted third molars. The patients were randomly subdivided and the split mouth technique was used in which each side (left or right) of the mouth was randomly assigned to two treatment groups. Hence each patient served as their own control. In one group, a piezoelectric handpiece was used, while a conventional handpiece was used for the second group.All aspects of preoperative care, general anaesthesia, surgery and post‐operative care were standardised for the two groups. The following parameters were recorded; time of surgery, bleeding during surgery, post‐operative swelling, post‐operative pain, associated complications and post‐operative nerve injury.ResultsNo statistically significant difference was found between the groups in terms of pain and swelling. There was less bleeding with the use of the piezoelectric device as compared with the standard surgical handpiece; however, the surgical time was longer. There were no reports of trauma to the lips or intra‐oral soft tissue. There were two incidences (6.7%) of post‐operative paraesthesia in the standard surgical handpiece group.ConclusionsThe use of a piezoelectric device is an acceptable alternative to the standard surgical handpiece in third molar surgery. Its use is advocated in difficult cases especially where there is inferior alveolar nerve approximation.

Comparison of Surgical Outcome after Impacted Third Molar Surgery Using Piezotome and a Conventional Rotary Handpiece.

Background and Aim:One of the most commonly performed surgical procedures by oral and maxillofacial surgeons all over the world is the removal of impacted teeth. The most critical and important steps in third molar extraction are bone cutting or osteotomy. Many techniques are used for this purpose including chisels and mallet, rotary instruments, and ultrasonic-based bone cutting instruments. Piezotome is newer and innovative device for osteotomy based on piezoelectric vibrations. Piezotome is considered very efficient in performing osteotomy because of its selective cutting; being inert against soft tissues, including nerves and blood vessels. The aim of this study was to compare the surgical outcome of third molar surgery using conventional handpiece and piezotome with all other criteria remaining same for all the individuals.Materials and Methods:All patients reporting to the Department of Oral and Maxillofacial surgery, Manipal College of Dental Sciences, Mangalore, for impacted mandibular third molar removal were screened. A total of 30 patients with same Pederson difficulty index for bilateral impacted third molar were selected for the study. The study involved the use of piezotome on one side (Side A) and rotary technique (Side B) on the other side for osteotomy on the same patient with an interval of 1 month. Therapeutic management was same for both the sides. Operating time was recorded in each surgery. Patients were examined postoperatively on 1st, 3rd, and 7th day and pain, edema, trismus, paresthesia, and dry socket were evaluated and compared on both the sides. Data collected were analyzed statistically.Results:The mean operating time was 48.13 min in piezotome (Side A) and 32.90 min in conventional handpiece (Side B) which was statistically significant (P < 0.001). Furthermore, there was statistically significant difference (P < 0.001) in the level of pain (P < 0.001), number of analgesics taken (P < 0.001), and trismus (P < 0.01) on 1st, 3rd, and 7th days postoperatively. There was no statistically significant difference in edema between the two sides. Paresthesia was present in one patient (3.3%) in Side B, while no paresthesia was present in Side A. No incidence of alveolar osteitis was reported on both the sides.Conclusion:Operating time with piezotome was more than that of conventional handpiece, but the postoperative responses such as pain, trismus, and edema were less in piezotome. Hence, despite being a slower procedure, piezotome can be an effective alternative for osteotomy in impacted third molar surgery. We recommend using piezotome for bone cutting and conventional rotary handpiece for tooth sectioning in order to obtain favorable outcomes as well as decreasing the operating time.

Ablative Potential of Er:YAG Laser in Dentin: Quantum Versus Variable Square Pulse.

The primary objective of this study was to compare the dentin ablation volume and ablation rate of quantum square pulse (QSP), using two different pulse energy settings plus a new digitally controlled dental laser handpiece (X-Runner), with those of variable square pulse (VSP), using three different pulse durations. The secondary objective was to examine, by scanning electron microscopy (SEM), the surface effects of ablation with the different Er:YAG laser modes on the dentin surfaces. The available literature has limited data on the efficiency of different operating modes, pulse durations, and the new digitally controlled handpiece of the Er:YAG laser on human dentin. Freshly extracted human molars (n = 72) were divided into two experimental groups (n = 36 each): (1) QSP group, and (2) VSP group. Each group was randomly divided into three subgroups (n = 12 each). In the QSP group, preparations in dentin were performed using 250 and 500 mJ of pulse energy with the conventional handpiece, and with the X-Runner handpiece set at 250 mJ pulse energy. In the VSP group, cavity preparations were performed using three pulse variables: super short pulse (SSP), micro short pulse (MSP), and short pulse (SP). Cavity preparations were made in dentin at time intervals of 1, 2, and 5 sec. A laser triangulation profilometer was used to determine cavity volumes. Surface analysis of the ablated dentin specimens was performed by SEM. For time intervals of 1 and 2 sec, ablated volume and ablation rate for QSP-500 mJ were significantly higher than for all other groups (p < 0.0001). For the 5-sec time interval, X-Runner and QSP-500 mJ were the most efficient in dentin ablation (p < 0.0001). Dentin surfaces were free of smear layer in all groups. The most efficient modes of dentin ablation in the study were the QSP-500 mJ and X-Runner groups. Dentin surfaces were free of smear layer in all groups.

Evaluation of root-end cavity preparation using erbium, chromium:yttrium, scandium, gallium, and garnet laser, ultrasonic retrotips, and conventional burs

Aim: To compare root-end cavities prepared with ultrasonics (Group A), with those created by burs in a conventional handpiece (Group B) and erbium, chromium:yttrium, scandium, gallium, and garnet (Er, Cr:YSGG) laser (Group C). Materials and Methods: After root canal instrumentation and filling, apices of 60 single-rooted teeth were resected. Retrograde Class I cavities 3 mm deep were prepared using ultrasonic retro-prep tips (Group A), round burs (Group B), and Er:YSGG laser (Group C). An ultrasonic unit was used with computed tomography-5 retrotip at the frequency of 32 KHz. Laser beam parameters were a pulse of very short duration (100 s), energy of 280 mJ, and repetition rate of 10 Hz. The apical root portion and root-end cavities were replicated and prepared for stereomicroscopic analysis. Results: The degree of chipping associated with the margin of the root-end cavities and the incidence of root face cracks were noted. Marginal chipping of root-end cavities prepared using ultrasonic instrumentation was significantly higher than that produced by bur (P < 0.001) or laser, with laser group showing the least amount of chipping. Conclusion: There was a significant difference between the number of cracks produced by the three methods, with the laser group having the least number of cracks and marginal chipping.

Piezosurgery or Conventional Rotatory Instruments for Inferior Third Molar Extractions?

The purpose of this study was to compare the discomfort and surgical outcomes of a piezosurgery device with those of rotatory instruments in lower third molar extraction. A split-mouth, randomized, unblinded clinical study was designed; the 2 molars had to have the same extraction difficulty score. The test side was extracted using a piezosurgery technique and the control side was extracted using a conventional handpiece. The primary endpoint was patient discomfort evaluated with the Postoperative Symptom Severity (PoSSe) scale, which was administered to each patient; secondary endpoints were pain, trismus, swelling, and surgical time evaluation. Paired-samples t test and repeated-measures analysis of variance were used to compare outcomes within patients. Ten consecutive patients (6 female, 4 male; mean age, 22.4 ± 2.3 yr) were recruited. The total score on the PoSSe scale was significantly lower for piezosurgery compared with the conventional rotating handpiece (24.7 ± 10.3 vs 36.0 ± 7.6; t = -4.27; P = .002). Moreover, postoperative swelling 1 week after surgery was significantly lower for piezosurgery than for the conventional rotating handpiece (2.75 ± 0.23 vs 3.1 ± 0.39 cm; t = -2.63; P = .027). Piezosurgery was associated with less postoperative discomfort and yielded better results for swelling. Piezosurgery seems to be a good technique in daily surgical practice, especially if applied in the critical steps in which safety and respect for soft tissue, bone, and nerves are necessary.

Comparative evaluation of surgical outcome after removal of impacted mandibular third molars using a Piezotome or a conventional handpiece: a prospective study

Our aim was to compare the use of a conventional rotary handpiece and a Piezosurgical unit for extraction of lower third molars. We studied 40 patients, who were allocated alternately to have the third molar removed with either the handpiece or the Piezosurgical unit. Pain, trismus, and oedema were evaluated at baseline and then postoperatively, together with paraesthesiae, on postoperative days 1, 3, 5, 7, and 15. Damage to surrounding tissue was checked on the same day whereas dry socket was evaluated from postoperative day 3 onwards. More patients complained of pain in the conventional group, they also required more analgesics, and they developed trismus more often than in the Piezosurgery group. There was also significantly more postoperative swelling in the conventional group. Patients were also evaluated using the subjective Postoperative Symptom Severity (PoSSe) scale. Our results suggest that apart from some inherent limitations with the Piezotome, it is a valuable alternative for extraction of third molars.

Case Report: Air Abrasion Cavity Preparation for Caries Removal in Paediatric Dentistry

Background: Air abrasion is a technique for removing dental caries and it has been reintroduced into the clinical setting as a result of improvements in equipment in association with both adhesive material development and minimally invasive restorative philosophy. Case report: A 6-year-old girl attended the Paediatric Dental Clinic of University of Rio de Janeiro, presenting with high caries activity which had previously been treated with diet counselling, oral hygiene instructions and adhesive restorations with composite resins using conventional rotary handpiece cavity preparation. Treatment: An adhesive restoration using air abrasion system for cavity preparation was the treatment proposed for removing the carious lesion on the palatal surface of tooth 83. This was carried out and was deemed to be acceptable to the child. Follow-up: Two years after the restorative procedure the patient presented with her restored teeth in perfect condition.

Avaliação do desempenho da tecnologia NeoSoniX TM em cirurgias de catarata

The techniques and results of cataract surgery have improved dramatically with technological advancements. One of the reasons for this improvement would be the reduced use of ultrasound with the new phacoemulsification devices. The objective of this study is to confirm the theoretical advantage of the NeoSoniX handpiece. The authors compared the results of the parameters recorded by the Legacy phacoemulsification system during 300 cataract surgeries performed with the use of the conventional ultrasound handpiece and 100 performed with the innovative Neosonix. All surgeries were performed by the same senior surgeon, using the same surgical technique. The choice of handpiece was random. The handpieces were compared considering cataract grade of hardness, in relation to parameters of ultrasound time, amount of balanced saline solution, and percentage of average power used during surgery. The analysis performed retrospectively on a chronological series of cases showed that the time of ultrasound used with the NeoSoniX handpiece was inferior to that with the conventional handpiece, for any cataract grade of hardness (p<0.000001). The volume of balanced saline solution used during surgical procedures was smaller, favoring the NeoSoniX technology (p<0.000001). In relation to the percentage of ultrasound energy used with the different technologies, an inferior value was found in the group who underwent surgery with the use of the NeoSoniX handpiece (p<0.000001). Based on the information provided by these surgeries, we may claim that there was a significant superiority when using the NeoSoniX handpiece in comparison to the conventional Legacy machine handpiece in cataract surgeries, regardless of cataract grade.

A newly modified 595-nm pulsed dye laser with compression handpiece for the treatment of photodamaged skin

The pulsed dye laser set the standard of care for the treatment of vascular lesions, and recent modifications have enabled improved efficacy with fewer side effects. An investigational high energy, variable pulse duration pulsed dye laser has been modified to treat both vascular and pigmented lesions associated with photoaging. Each laser pulse is comprised of a sequence of eight uniform micropulses, which evenly distribute the pulse energy, effectively increasing the purpura threshold at any given fluence. Pigmented lesions are treated with a compression handpiece (CHP) that removes competing vascular target from the field, and helps to prevent purpura. This pilot study was undertaken to determine the optimum laser settings, and to investigate the ability of this device to improve vascular and pigmented lesions associated with photoaging. Twenty-four patients with photoaged skin and phototype I-III were enrolled in the study. Thirteen received treatment for vascular and pigmented lesions, and 11 subjects were treated for pigmented lesions alone. Subjects received one to three treatments at 3-4 weeks intervals, and underwent 3- and 12-week follow-up evaluation. The degree of improvement was assessed by subject evaluation as well as comparison of standardized digital photographs by three independent dermatologists. Background erythema was treated with a 12-mm spot size, at a fluence of 7 J/cm(2), and a pulse width of 10 ms. The cryogen cooling was set at 30 mseconds with a 30 ms delay. Individual telangiectasias were treated with a 5- or 7-mm spot size at fluences of 9-14 J/cm(2) and pulse widths of 6-20 mseconds. Pigmented lesions were treated using a 5- or 7-mm spot size, with energy of 9-15 J/cm(2) and a pulse width of 1.5-10 ms without cooling. The CHP had a 7-mm spot size, and fluences of 9-16 J/cm(2), and pulse widths of 1.5 or 3 ms were used in the treatment of pigmented lesions. The treatment was well tolerated without the use of topical anesthetic. All subjects noted improvement in the both vascular and pigmented lesions, and were satisfied with their outcomes. Objectively, there was moderate improvement in background erythema, telangiectasia, and pigmented lesions. Three subjects who were treated with sun tans developed transient hypopigmentation and two subjects developed a transient textural change following pulse stacking for the treatment of pigmented lesions with the conventional handpiece. Purpura was noted in all patients treated for pigment with the conventional handpiece at pulsewidths less than 6 mseconds, as compared to only one that was treated with the CHP. Three patients treated in rapid succession for vascular, and then pigmented lesions with the CHP exhibited purpura, which was prevented in future treatments with 1-2 minutes of topical ice cooling between passes. This novel 595-nm pulsed dye laser, with a modified pulse sequence and CHP, now has the versatility to safely treat both pigment and vascular changes associated with photoaging.

Laser-osteotomy induced changes in bone

Abstract Objective: To describe changes caused by clinically used lasers during osteotomy procedures. Temperature rise and potential thermal damage to tissue during ablation of bone using a super-pulsed carbon dioxide laser of 9.6-μm wavelength and an Er:YAG laser, equipped with a water-cooling spray and scanner system were studied. Background data: There has been no recent study comparing the super-pulsed CO 2 laser using a 9.6 μm wavelength to the Er:YAG laser with regard to their thermal effects on bone. In addition, the use of such laser systems under clinical conditions and histological evaluation in human bone has not been reported so far. Methods: In this study, two different types of samples were investigated to yield data most consistent with a typical clinical situation. Porcine slices and mandibular bone segments were studied at a drilling depth with a range of 0.5–0.7 and 0.6–0.97 mm, respectively. A control group treated with a conventional hand piece was compared to the laser groups. Lasers were also used in an OR-setting to evaluate clinical use and yield histological samples from human bone. Results: In the CO 2 laser groups demonstrating the highest elevation in temperature of the studied bone slices a mean temperature rise of less than 1.88 °C was noted. The Er:YAG revealed the highest mean temperature rise with 3.3 °C. Conventional drilling with a comparable drilling rate resulted in a mean rise of 1.43 °C. The laser groups of mandibular bone segments revealed a constant decrease in temperature hence the conventional drill rose to a mean temperature of 3.7 °C. Scanning electron microscope observations were lacking the typical morphological changes seen in earlier studies, specifically extensive melting, charring or cracking. Microscopic histology revealed minimal tissue changes limited to a few μm. Conclusions: A maximum rise of mean temperature to 1.88 °C, well below the critical margin of 7 °C, in closest proximity to the bone marrow and the morphological unaltered bone surfaces, demonstrate the safety and tissue preserving capability of the superpulsed 9.6 μm CO 2 laser. All three modalities are considered to preserve tissue not exceeding critical temperatures. The laser caused an even lower temperature rise than conventional drilling when used for osteotomies on bone segments. Moreover, the laser showed acceptable efficacy with drilling times comparable to the conventional dental drill. The clinical use of a 9.6 μm CO 2 laser as a bone-cutting tool can be considered to preserve tissue with minimum histologic effects.

Endothelial cell integrity after phacoemulsification with 2 different handpieces

Purpose: To investigate corneal endothelial cell loss in fresh phakic human autopsy cadaver eyes after phacoemulsification (PE) with a conventional handpiece or a new oscillatory handpiece. Setting: Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Methods: Twenty fresh phakic human autopsy globes were randomized to PE with a conventional handpiece (n = 10) or an oscillatory handpiece (n = 10). The main parameters evaluated were age, nucleus density, amount of ophthalmic viscosurgical device (OVD) used, and mean PE time and ultrasound (US) power. After surgery, the corneas were excised and the endothelia were vitally stained with trypan blue and alizarin red. Light microscopy was used to assess the endothelial cell loss. Results: The mean age, density of the nucleus, OVD used, and US power were similar between the groups. The mean PE time was less with the NeoSoniX handpiece (0.71 minutes ± 0.39 [SD]) than with the conventional handpiece (1.05 ± 0.53 minutes). The mean number of dead endothelial cells was significantly lower in the oscillatory handpiece group (31.3 ± 24.2 cells/mm 2) than in the conventional handpiece group (60.4 ± 46.8 cells/mm 2) ( P<.001, Mann-Whitney rank sum test). Conclusions: Less corneal endothelial cell loss occurred after PE with an oscillatory handpiece than with a conventional handpiece. Further randomized clinical trials are recommended to validate this study.

Laser-induced temperature changes in dentine.

The purpose of this work is to study the temperature rise and potential thermal damage caused during ablation of human dentine using a super pulsed carbon dioxide laser of 9.6-microm wavelength, equipped with a water-cooling spray and scanner system. There have been no reports on thermal effects of super pulsed CO2 laser of 9.6 microm wavelength on human dentine recently. Two different types of samples were investigated to yield data most consistent with a typical clinical situation. Human dentine slices and crown segments were studied at a drilling depth of 1.0 +/- 0.1 mm and 2.5 +/- 0.5 mm, respectively. A control group treated with a conventional hand piece was compared to four laser groups with settings varying from 2 to 8 W. In the laser group demonstrating the highest elevation in temperature of the four studied, dentine slices lased at 2 W for 15 sec showed a mean temperature rise of less than 1.68 degrees C at an ablation rate of 0.86 +/- 0.08 mm. Conventional drilling with a comparable ablation rate of 0.76 +/- 0.59 mm resulted in a mean rise of 2.87 degrees C. The laser groups of crown segments revealed a constant decrease in temperature. SEM observations were lacking the typical morphological changes seen in earlier studies, specifically extensive melting, charring or cracking. A maximum rise of mean temperature to 1.68 degrees C in closest vicinity to the pulpal chamber and the morphological unaltered dentine surfaces demonstrate the safe and tissue preserving character of the superpulsed 9.6 microm CO2 laser. The laser caused an even lower temperature rise than conventional drilling. Moreover, the laser showed acceptable efficacy with ablation rates that did not significantly differ from the conventional dental drill.

Pulpal response to exposure with Er:YAG laser

Objective: The purpose of this study was to evaluate the pulpal response to the Er:YAG laser after accidental exposure of the pulp. Study Design: Cavities were prepared, and pulps were exposed by either Er:YAG laser or mechanically by a slow-speed conventional handpiece (control group) in 76 maxillary first molars of male Wistar rats. Rats were killed immediately, at 3 days, 1 week, and 2 weeks. Histopathologic examinations of the pulp at the exposure site were performed and evaluated with the Mann-Whitney U test (P < .05). Results: The Er:YAG laser group showed no bleeding and no dentin chips at the exposure site immediately after pulp exposure. However, they displayed an area of blood extravasation near the exposure site. Subsequently, the Er:YAG laser group formed dentin bridges at the exposure site more frequently than the control group. The Er:YAG laser group demonstrated more reparative dentin formation near the exposure site than the control group, especially at 2 weeks, which was highly significant (P < .01). Conclusion: According to the results of this study, Er:YAG laser–exposed pulp tissue demonstrated good healing capacity with the formation of a dentin bridge and reparative dentin. However, further investigations are suggested to study the effect of the blood extravasation, which appeared near the laser exposure sites. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2001;91:222-9)

Advances in operative dentistry and fixed prosthodontics.

The rapid developments in biomaterials has led not only to improved materials but also to the development of clinical techniques made possible by these advances. Adhesive dentistry remains one of the fastest changing fields and this will most likely continue well into the next decade. Patients' aesthetic awareness and, to some extent, concern about amalgam has produced a growing demand for posterior tooth-coloured restorations. Originally this was met by ceramo-metal crowns and subsequently by the development of posterior composite resins. Recent development of stronger ceramics and better luting have now made all-ceramic restorations possible in posterior sites. Several new techniques for cavity preparation are emerging as alternatives to the conventional handpiece while the quest for amalgam alternatives continues. As with all recent developments there are, by definition, few long-term clinical data yet available to allow a comprehensive evaluation of the relevant materials and techniques. This paper is a summary of the most significant recent advances in fixed prosthodontics and operative dentistry.

Histological evaluation of repair using a bioresorbable membrane beneath a resin-modified glass ionomer after mechanical furcation perforation in dogs' teeth

Resorbable barriers have been shown both clinically and histologically to produce favorable periodontal regenerative outcomes. The purpose of the present study was to evaluate the histological response to one such resorbable barrier (Atrisorb) when used as a matrix under a resin-modified glass ionomer (RMGI) sealant in the repair of furcation perforations in experimental animals. After anesthesia, pulp extirpation and filling of radicular canals with zinc oxide-eugenol cement, furcal perforations were made in 30 lower premolar (P2, P3, and P4) teeth of labrador dogs with a 1 mm diameter round bur in a conventional handpiece. The perforated teeth were randomly divided into two groups of 15 teeth. Group 1 teeth were treated with RMGI alone and group 2 with the resorbable barrier under RMGI. Six teeth without perforations served as negative controls. Pulp chambers of all teeth were filled with RMGI cement. Animals were sacrificed after 3 months. The teeth and the surrounding structures were processed for light microscopy. There were no differences found between results for glass ionomer alone and barrier with glass ionomer. The conclusion of this study is that placement of a resorbable barrier at the pulp chamber aspect of a furcation perforation did not result in superior healing, compared with the use of resin-modified glass ionomer alone.

Prevention of infection in dental procedures

The efficacy of a newly-developed anti-cross-contamination device in dentistry, the Air Flushing Clean System (AFCS), was tested under experimental and clinical conditions. In the experimental situation, a dental air turbine handpiece with or without AFCS was contaminated with two bacterial strains, Staphylococcus aureus FDA209P and Streptococcus mutans ATCC25175. After contamination with these bacteria, the handpieces were subjected to two disinfecting methods. Residual bacteria inside the handpiece or an air/water line were cultured and counted, and compared with controls. In this experiment, with AFCS but no dental vacuum suction, wiping of the handpiece with 70% ethanol gauze reduced the count of S. aureus by 99%. No bacterial contamination in the air/water line was detected after exchanging with an autoclaved handpiece. With AFCS and dental vacuum suction, bacterial contamination in the air/water line, as well as in the interior of the handpiece, was not detected. These results indicate that AFCS could reduce bacterial contamination within the air turbine handpiece more effectively than the conventional handpiece regardless of whether or not the dental vacuum suction was used.