Subcutaneous emphysema to the head and neck resulting from a dental crown preparation.

CASE REPORT: A 59-year-old African-American female presents with subcutaneous emphysema to the head and neck region resulting from routine dental treatment with a high speed air-driven handpiece. The patient had a chief complaint of generalized edema, dysphagia and pain to her face and neck. The patient subsequently was admitted to the intensive care unit for airway monitoring. PURPOSE: To alert the dental community about the incidence of iatrogenic subcutaneous emphysema from a routine dental procedure, and how to recognize and manage its occurrence.

Effects of irrigation temperature on heat control in vitro at different drilling depths.

PURPOSE: Thermal injury during implant bed preparation has a major influence on implant osseointegration and survival. This study investigated the effectiveness of the temperature of the saline solution used for heat control during drilling. MATERIAL AND METHODS: Fresh frozen edentulous segments of bovine mandibles were sectioned into 12 x 6 cm pieces. Thermoresistors were placed 0.5 mm from the drilling cavity walls, at depths of 3, 7, and 12 mm. Signals from the three thermoresistors were analyzed using ORIGIN 5.0 software. RESULTS: The maximum temperatures during drilling without irrigation were 50.9, 47.4, and 38.1 degrees C at depths of 3, 7, and 12 mm, respectively. With irrigation using saline at 25 and 10 degrees C, the maximum temperatures at a depth of 12 mm were 37.4 and 36.3 degrees C, respectively. All other measurements with both 25 and 10 degrees C saline were below body temperature. DISCUSSION AND CONCLUSION: This experimental in vitro study showed that more heat was generated in the superficial part of the drilling cavity than at the bottom. Therefore, external irrigation at room temperature can provide sufficient cooling during drilling. Lower temperature saline was more effective in cooling the bone, and irrigation of the site should be continued between the drilling steps.

An in vitro investigation of the effectiveness of bioactive glass air-abrasion in the 'selective' removal of orthodontic resin adhesive.

The process of clinically debonding orthodontic brackets causes histomorphological damage to enamel that needs to be quantified and minimized. This study compared three methods for removing residual resin adhesive following bracket debonding. The surface finish following removal of residual adhesive using a slow-speed eight-bladed tungsten carbide bur (group 1), alumina air-abrasion (group 2), and bioactive-glass air-abrasion (group 3) and following polishing, was examined using scanning electron microscopy imaging of resin replicas. Contact profilometry was used to image surfaces before and after debonding for quantifiable volumetric analysis of enamel damage. Surface scarring was seen on scanning electron micrographs from group 1, a sharp pitted surface was identified in group 2, while group 3 exhibited similar, but subjectively smoother, pits. The surface finish following polishing was similar for groups 2 and 3 but did not completely remove the scarring evident from group 1. Quantifiable enamel lost was as follows: group 1, 0.285 mm(3); group 2, 0.386 mm(3); and group 3, 0.135 mm(3); statistical differences were observed between groups 2 and 3. From these results, bioactive-glass air-abrasion more consistently caused less physical damage to enamel and achieved a clinically smooth surface finish following polishing and is therefore to be recommended for clinical use.

Comparison of operative procedure variables on pulpal viability in an ex vivo model.

AIM: To measure and compare the responses of pulp tissue to cavity preparation and restoration variables using a novel tooth slice culture model. METHODOLOGY: Experimental cavities (265) were continuously cut, under carefully controlled conditions, into the dentine of the labial aspect of 28-day-old Wistar rat incisors, and slices of these teeth maintained in organ culture for up to 2 weeks. The experimental variables examined were: the preparation method, remaining dentine thickness, coolant, drill speed, conditioning with EDTA and filling materials. The reactions of the dentine-pulp complex to the experimental variables were measured using pathohistometric analysis and the correlations between variables were determined using analysis of variance statistical tests. RESULTS: In rank order of surgically induced restorative pulpal injury, from the most to the least injurious were: remaining dentine thickness, absence of coolant during cavity preparation, bur speed, cavity conditioning treatments and the filling material. CONCLUSIONS: To reduce pulp injury and to promote pulpal repair activity, the correct use of appropriate materials are important. However, of relatively greater importance is the operative technique adopted, the need to avoid the excess removal of dentine and to minimize trauma during preparation.

Temperature rise in the pulp chamber during different stripping procedures.

OBJECTIVE: To measure the temperature changes in the pulp chamber when different stripping procedures were used without any type of coolant. MATERIALS AND METHODS: Ninety intact, freshly extracted human teeth were used in this study. The teeth were separated into nine groups of 10 teeth each. Mesial and distal sides of the teeth were used separately. The stripping procedures were performed on three different tooth groups (incisor, canine, premolar) with a metal handheld stripper, perforated stripping disk, or tungsten carbide bur. A J-type thermocouple wire was positioned in the center of the pulp chamber and was connected to a data logger during application of stripping procedures. The results were analyzed by analysis of variance (ANOVA) and the Duncan test. RESULTS: Two-factor ANOVA revealed significant interaction between the stripping procedure and the tooth type (P = .000). The results of this study demonstrate that tungsten carbide burs used on mandibular incisors had the highest temperature variation (DeltaT) values, which exceeded the critical level (5.5 degrees C), and this was significantly higher than those of the other stripping procedures (DeltaT: 5.63 +/- 1.73 degrees C). On the other hand, six of the nine groups also produced temperature increases above the critical level (5.5 degrees C) for some of the specimens. CONCLUSIONS: Frictional heat is a common side effect of stripping procedures, and appropriate measures (ie, cooling application) should be taken particularly for high-speed hand-piece stripping of mandibular incisors.

Bacterial aerosols in dental practice - a potential hospital infection problem?

Aerosols containing microbes from the oral cavity of the patient are created when using modern high-speed rotating instruments in restorative dentistry. How far these aerosols spread and what level of contamination they cause in the dental surgery has become a growing concern as the number of patients with oro-nasal meticillin-resistant Staphylococcus aureus colonization has increased. The present study aimed to determine how far airborne bacteria spread during dental treatment, and the level of contamination. Fall out samples were collected on blood agar plates placed in six different sectors, 0.5-2m from the patient. Restorative dentistry fallout samples (N=72) were collected from rooms (N=6) where high-speed rotating instruments were used, and control samples (N=24) were collected from rooms (N=4) used for periodontal and orthodontic treatment where rotating and ultrasonic instruments were not used. The collection times were 1.5 and 3 h. In addition, samples were taken from facial masks of personnel and from surfaces in the rooms before and after disinfection. After 48 h of incubation at 37 degrees C, colonies were counted and classified by Gram stain. The results showed significant contamination of the room at all distances sampled when high-speed instruments were used (mean 970 colony-forming units/m2/h). The bacterial density was found to be higher in the more remote sampling points. Gram-positive cocci, namely viridans streptococci and staphylococci, were the most common findings. The area that becomes contaminated during dental procedures is far larger than previously thought and practically encompasses the whole room. These results emphasize the need for developing new means for preventing microbial aerosols in dentistry and protection of all items stored temporarily on work surfaces. This is especially important when treating generally ill or immunocompromised patients at dental surgeries in hospital environments.

Effect of rotary instrumentation on composite bond strength with simulated pulpal pressure.

This study evaluated the effect of cutting teeth with different types of burs at various speeds on shear bond strength using Prime and Bond NT (Dentsply/DeTrey). A simulated pulpal pressure of 25-mmHg, equivalent to 34 cmH2O, was created in a false pulpal chamber filled with distilled water and maintained for seven days. The human teeth were divided into six groups of 10 teeth each: fine grit straight fissure diamond bur in air rotor (DA), fine grit straight fissure diamond bur in micromotor (DM), crosscut fissure carbide bur in air rotor (CCA), crosscut fissure carbide bur in micromotor (CCM), plain fissure carbide bur in micromotor (CM) and #600-grit silicon carbide paper (SiC). The tooth surfaces in these groups were cut under copious air-water spray and treated with Prime and Bond NT after etching with 38% phosphoric acid. Composite restorations were then prepared with TPH spectrum (Dentsply/ DeTrey). After soaking in water at 37 degrees C for 24 hours, the specimens were loaded at a 45 degrees angle to their longitudinal axes by using a Z 010 Universal Testing Machine (Zwick), and shear bond strengths were determined at a crosshead speed of 2 mm/minute. All of the specimens were then observed under Stereomicroscope at 10x. Statistical analysis was made using one-way and two-way ANOVA and t-test (p < 0.05). The bond strengths achieved with a fine grit straight fissure diamond bur, a crosscut fissure carbide bur in air rotor and a crosscut fissure carbide bur in micromotor, were significantly higher than a fine grit straight fissure diamond bur, a plain fissure carbide bur and #600-grit silicon carbide abrasive paper in the micromotor. Therefore, selecting an appropriate bur and its speed may improve bonding for adhesive systems, although crosscut fissure carbide burs produced high bond strengths at either speed used.

Cervicofacial and mediastinal emphysema complicating a dental procedure.

Cervicofacial subcutaneous emphysema is an infrequently reported sequela of dental surgery. It may be caused by the inadvertent introduction of air into the soft tissues during procedures using high-speed, air-driven handpieces or air-water syringes. In this paper, we present a case in which subcutaneous emphysema developed in a middle-aged woman following routine restorative treatment. We review the features of the condition and its treatment and discuss means of prevention.

Fracture Forces of Dentin after Surface Treatment with High Speed Drill Compared to Er:YAG and Er,Cr:YSGG Laser Irradiation.

Dental tooth restorative procedures may weaken the structural integrity of the tooth, with the possibility of leading to fracture. In this study we present findings of coronal dentin strength after different techniques of surface modification. The fracture strength of dentin beams after superficial material removal with a fine diamond bur high speed drill hand piece, Er:YAG (2.94 µm, 8 J/cm(2)), and Er,Cr:YSGG (2.78 µm, 7.8 J/cm(2)) laser irradiation slightly above the ablation threshold was measured by a four-point bending apparatus. Untreated dentin beams served as a control. A total of 58 dentin beams were manufactured from sterilized human extracted molars using the coronal part of the available dentin. Mean values of fracture strength were calculated as 82.0 ± 27.3 MPa for the control group (n = 10), 104.5 ± 26.3 MPa for high speed drill treatment (n = 10), 96.1 ± 28.1 MPa for Er,Cr:YSGG laser irradiation (n = 20), and 89.1 ± 36.3 MPa for Er:YAG laser irradiation (n = 18). Independent Student's t-tests showed no significant difference between each two groups (p > 0.05). Within the parameter settings and the limits of the experimental setup used in this study, both lasers systems as well as the high speed drill do not significantly weaken coronal dentin after surface treatment.

Subgingival debridement with a teflon-coated sonic scaler insert in comparison to conventional instruments and assessment of substance removal on extracted teeth.

OBJECTIVE: Previous studies have shown that endotoxins are located on the periodontally diseased root cementum and not within it. To what extent a Teflon-tubed sonic scaler was capable of removing bacterial deposits in comparison to conventional scaling instruments, and the resulting root surface roughness and root surface topography, were recently assessed. The objective of the present study was to evaluate how much root cementum is removed with these instruments. METHODS AND MATERIALS: Eighty-two teeth were treated subgingivally on one approximal site either with a Teflon-coated sonic scaler insert (tSS), a Gracey curette, a conventional sonic scaler (SS), a piezoelectric ultrasonic scaler insert (US), or an oscillating Periotor insert (PT) before extraction. The untreated site served as control. The width and length of cementum removal were compared histomorphometrically. Nonparametric analyses were carried out for statistical comparison. RESULTS: The US, PT, and tSS inserts removed less substance than the curettes or SS inserts. The cementum removed was 40 microm for root surfaces treated with the curette or SS, 30 microm for those treated with US, 20 microm for PT, and 17 microm for tSS. CONCLUSION: The Teflon-coated sonic scaler inserts can be a reasonable choice for gentle maintenance treatment of compliant patients with good plaque control, and little or no subgingival deposits.

Thermal changes in the pulp chamber during different adhesive clean-up procedures.

The aim of this in vitro study was to measure the temperature changes in the pulpal chamber when different adhesive clean-up procedures were used. Ninety intact extracted human maxillary central incisors were used in the study. The teeth were divided into six groups of 15 teeth each. The removal of the remaining composite on the tooth surface was performed with a tungsten carbide bur. The residual adhesive was removed using a high-speed handpiece with and without water cooling and a contra-angle handpiece with and without water cooling at high and low speeds. A J-type thermocouple wire was positioned in the center of the pulp chamber. The results were analyzed with analysis of variance (ANOVA) and the Tukey-honestly significant difference test. Two-factor ANOVA revealed significant interaction between the handpiece type and water cooling. In this study, the high-speed contra-angle handpiece without water cooling group had the highest deltaT values (7.58 degrees C+/-1.84 degrees C) among all the clean-up procedures. The decrease in pulpal temperature with water cooling was -5.34 degrees C for the handpiece, -5.36 degrees C for the low-speed contra-angle handpiece and -4.98 degrees C for the high-speed contra-angle handpiece. Clinicians should be aware of the potential thermal damage to the pulp, which may result from long clean-up procedures without water cooling. Adhesive removal procedures should be performed with adequate water cooling to prevent temperature increases that might be harmful to pulpal tissues.

Preventing root tip loss in the maxillary sinus during endodontic surgery.

Exclusion of infected root tips, dentinal debris, and inflammatory tissue from the maxillary sinus during endodontic surgery is imperative. A simple technique for preventing accidental root tip intrusion into the maxillary sinus using a 6-0 suture and needle and a hole prepared in the root tip with a #2 round bur prior to apicoectomy is presented.

Temperature changes in bovine mandibular bone during implant site preparation: an assessment using infra-red thermography.

OBJECTIVES: Changes in bone temperature during the sequence of drilling for implant site preparation using the Branemark technique were monitored using infra-red thermography. METHODS: Bovine mandibles were used to provide cortical bone of a similar quality to human mandibular bone. To ensure the consistency in the drilling procedure, one operator used a conventional dental handpiece with a motor provided by Nobelpharma. The manufacturer's specifications were followed during the implant site preparation, except that no irrigation was employed since infra-red radiation does not transmit through water. Thermal images were recorded using the Thermovision 900 system. A sequence of images was recorded during implant site preparation. Three drills were examined in terms of temperature changes during drilling over the entire area involved. The three drills used were a round bur, which determines the site of the fixture, a spiral drill (2 mm twist drill) which establishes the direction of the implant and finally a pilot drill (3 mm) which progressively increases the diameter of the site. RESULTS: Average values (n = 10 drill sequences) for maximum recorded temperature (Max T degrees C), change in temperature (delta T degrees C) from baseline and the area of involvement (mm2) for each drill in the 10 drill sequences were as follows: round, spiral (2 mm) and pilot (3 mm) drills gave maximum temperatures of 82.7 degrees C, 130.1 degrees C and 126.3 degrees C, respectively. The changes in temperature, delta T degrees C, were 45.7 degrees C, 79.0 degrees C and 78.9 degrees C for the round, 2 mm twist and 3 mm pilot drill, respectively. The average areas recorded for the round, spiral and pilot drills were 49 mm2, 140.1 mm2 and 273.0 mm2, respectively. CONCLUSIONS: It is concluded that the methodology employed accurately recorded temperature changes at and around the dental implant site, and provided preliminary baseline data against which the cooling efficacy of different irrigant systems may be compared.

Histopathologic effects of kinetic cavity preparation for the removal of enamel and dentin. An in vivo animal study.

Recent developments in technology, direct placement restorative materials, and cavity preparation design have renewed interest in kinetic cavity preparation, a term to describe the use of air-abrasion for removal of tooth structure. This study compared the pulpal response of 120 teeth in mixed-breed dogs treated with four kinetic cavity preparation combinations of pressure (80 psi and 160 psi) and aluminum oxide particle sizes (27 microns and 50 microns) to those treated with high-speed rotary burs. Class V buccal preparations were made and restored with an interim material. Teeth were collected 72 hours after surgery, decalcified, sectioned, stained with hematoxylin and eosin, and blindly evaluated by two examiners at the minimal dentin thickness. Samples were graded for extent of displacement, disruption, inflammation, and necrosis of pulpal structures. Differences between groups were analyzed with the use of Bonferroni-adjusted multiple Mann-Whitney-Wilcoxon tests with p < 0.05 being significant. Higher pressures and smaller particles yielded significantly fewer pulpal effects than the high-speed treated teeth whereas lower pressures and larger particles were not significantly different for most effects evaluated. No adverse soft tissue effects were noted when kinetic cavity preparation was directed at attached gingiva.

Measuring harmful levels of bacteria in dental aerosols.

The potential spread of the bacteria in aerosols emphasizes the familiar triad--gloves, masks and eyewear--for all operative procedures.

Micro-cracking of tooth structure.

PURPOSE: To determine if the cutting procedure utilized in producing a cavity preparation, i.e., a high speed dental handpiece or an Er:YAG laser may be a factor in initiating the formation of micro-cracks during or after preparation of the cavity and before and after placing and curing the dental composite. METHODS: Class I occlusal and Class II MOD preparations were prepared in extracted third molars using a high speed dental handpiece equipped with a coarse diamond bur or with an Er:YAG laser at 260mJ and 25Hz. Composite was placed into the cavity level with the occlusal surface and bulk cured. The extreme factors of a coarse diamond bur and bulk curing of the composite were utilized to maximize the stresses at the tooth-composite interface. The teeth were vertically sectioned, facio-lingually, and examined, along with resin replicas, under a scanning electron microscope (SEM) to look for the presence of microcracks at the composite/enamel interface and composite/dentin interface. RESULTS: SEM examination indicated that micro-cracking of the tooth structure was not significant or consistent in any of the specimens examined. This study was unable to confirm that micro-cracks form at the composite/tooth interface.

Subcutaneous, orbital, and mediastinal emphysema secondary to the use of an air-abrasive device.

Subcutaneous emphysema can occur whenever compressed air is employed intraorally. A case is presented of subcutaneous, orbital, and mediastinal emphysema subsequent to the use of an air-abrasive device. The case is believed to be the first reported case of an air-abrasive-related emphysema and is presented as a cautionary report.

Heat propagation in dentin during instrumentation with different sonic scaler tips.

It is important to know how much heat is generated when a root surface is debrided with sonic scalers and if that heat can be released satisfactorily into the environment. The temperature changes that occurred in dentinal specimens treated with two different sonic scaler tips, used with and without coolant, were studied. Temperature increases of up to 4 degrees C were observed for both tips when a coolant was used. Heat propagation during instrumentation was dependent to a considerable degree on the temperature of the coolant. Sonic scalers should not be used without coolant, because the dentinal temperature may increase up to 35 degrees C, depending on the force of application. A high positive linear correlation was found between increase in temperature and force of application.

Emphysematous complications in dentistry, 1960-1993: an illustrative case and review of the literature.

Seventy-four reports of emphysematous complications in ambulatory dental patients, published in the English literature between the years 1960 and 1993, are reviewed, and an additional case of subcutaneous, retropharyngeal, and mediastinal emphysema following an impression-taking procedure for a crown preparation is presented. This rare complication occurred mainly in patients in the third and fifth decades of life, after dental procedures on the third molar, in particular during mandibular extractions and treatment on the right side. The use of an air syringe, high-speed handpieces, or their combination was reported in 71% of cases. Centripetal air dissection, with retropharyngeal and mediastinal emphysema, occurred in 35% of the patients, especially following extractions.