Full-thickness wounds resulting from 'do-it-yourself' cryolipolysis: a case study.

This report reviews the case of a 55-year-old woman who suffered frostbite while attempting a 'do-it-yourself' version of cryolipolysis without the guidance of a medical professional. Cryolipolysis is a well-understood process through which the careful application of below-freezing temperatures is used to induce adipose cell death while sparing the skin, reducing body fat. This patient used dry ice in lieu of professional medical equipment, resulting in 4% total body surface area full- and partial-thickness wounds to her abdomen. Ultimately, the more superficial wounds healed with xenograft and a silver-impregnated dressing. The superior, deeper wound was excised and primarily closed with a fleur-de-lis panniculectomy. Her hospital course and recovery were uneventful. This case illustrates how online information of dubious quality can put the uneducated patient at risk of injury. Health-care professionals should be aware of the questionable resources available online, and should help patients become more discerning consumers of online information. Strategies to prevent such injury should be developed on a national scale.

Support of occlusal enamel provided by bonded restorations.

In this in vitro study, the resistance to fracture of occlusal enamel supported by a bonded tooth-colored restorative material was compared to unsupported enamel and enamel supported by sound dentin. Eighty extracted human lower molars were sorted into five groups of 16 teeth each. Lingual cusps were removed. In Groups 2-5, dentin was removed from the facial cusps, leaving a shell of enamel. In Group 1, dentin was not removed. Group 2 remained unrestored. The groups in which a restorative material was inserted to replace missing dentin were as follows: composite (Scotchbond MP/Filtek Z250 [A2] in capsules, 3M); Group 4-resin-modified glass-ionomer (Fuji II LC [A2] in capsules, GC); Group 5-conventional glass ionomer (Fuji IX [A2] in capsules, GC). Specimens were thermocycled (1500 cycles, 6 degrees-60 degrees C, dwell 30 seconds), then mounted in die stone with lingual inclines of facial cusps approximately horizontal. The cusp ridges of the lingual inclines were flattened slightly using a horizontally mounted separating disk. Specimens were loaded evenly on flattened inclines in an Instron with a flat rectangular rod at a crosshead speed of 5 mm/minute. Data analysis was with one-way ANOVA and Student-Newman-Keul's test (F = 50.30, p < 0.0001). The bonded restorations provided significantly less enamel support than natural dentin and significantly more than when the enamel was left without support by dentin or a restorative material. There was no difference in support provided by the three restorative materials.

The use of dental amalgam in pediatric dentistry: review of the literature.

Dental amalgam is widely used as a restorative material even though it is not esthetic and there has been extensive anti-amalgam rhetoric. Although other materials have improved greatly, amalgam has the proven safety record and best cost-to-benefit ratio. Clinical evidence indicates that, in the posterior permanent dentition--where esthetics is not a primary concern--the small, minimally prepared, amalgam restoration, with its margins and any caries-susceptible fissures sealed with resin fissure sealant, is the restoration with the best survival. Amalgam also remains the best direct restorative option when larger restorations are required. In the primary dentition, the data indicates that resin-based composite and resin-modified glass-ionomer serve very well.

The whitening effect of bleaching agents on tetracycline-stained rat teeth.

This study compared the whitening effect of three bleaching agents on the teeth of rats and demonstrated differences in bleaching where dentin was exposed or enamel was thin. Thirty Albino rats were peritoneally injected with tetracycline solution daily for two weeks. Thirty-two disc-shaped specimens were cut from the crowns of incisors removed from sacrificed rats and were irradiated with UV light for 16 hours. Sections were stored in saline. Eight sections served as controls and were not bleached. Three bleaching agents (Opalescence, Rembrandt and Nite White) were applied to eight specimens each, five times a day for two weeks, and images of the sections were recorded at the following times: before bleaching (baseline), day 1, day 3, day 5, day 7, day 9, day 11 and day 14. Mean colors to demonstrate any change (deltaE) from baseline for each time period were as follows: control-9.78 (baseline), 9.17, 9.36, 9.65, 9.40, 9.99, 10.57, 11.36; Opalescence-10.08, (baseline) 7.63, 6.72, 6.04, 5.10, 4.87, 4.89, 4.27; Rembrandt-9.83 (baseline), 11.27, 9.55, 8.36, 7.75, 6.94, 7.11, 7.04; Nite White-10.44 (baseline), 9.92, 7.58, 6.80, 5.45, 5.05, 4.73, 4.01. All bleached teeth were lightened (p<.01). Another 56 tetracycline-stained rat incisors were UV irradiated for three days. Three different penetration depths were tested: penetration through lingual dentin and labial enamel (DN group), penetration through labial enamel only (RE group) and penetration through labial enamel covered with 1.0 mm human enamel (HE group). Specimens were bleached with Opalescence for one hour five times a day for one week or four weeks. A control group of unbleached teeth was also examined. Results (deltaE) were as follows: control--11.67; 1-week DN--13.55; 1-week RE--12.80; 1-week HE--12.07; 4-week DN--7.48; 4-week RE--7.50; 4-week HE--11.69. The color change in the 4-week DN and the 4-week RE groups showed the greatest reduction (p<.01).

The performance of bonded vs. pin-retained complex amalgam restorations: a five-year clinical evaluation.

BACKGROUND: The authors compared the clinical performance of complex amalgam restorations, replacing at least one cusp--retained either mechanically with self-threading pins or bonded--with a filled, 4-methacryloxyethyl trimellitate anhydride, or 4-META-based resin designed for amalgam bonding. METHODS: The authors placed 60 amalgam restorations (28 pin-retained and 32 bonded), each restoration replacing at least one cusp. They used self-threading stainless steel pins in the pin-retained group and a filled, 4-META-based bonding resin in the bonded group. For both groups, the authors left in place any retention form remaining after removal of an old restoration but did not enhance it. RESULTS: At four years, six restorations had failed. At five years, of the 40 restorations available for evaluation, three had failed, for a total of nine failed restorations; seven of those were pin-retained and two were bonded. Using the Fisher exact test to compare the groups at five years, the authors found no significant difference in failure rate, marginal adaptation, marginal discoloration, secondary caries, tooth sensitivity or tooth vitality. CONCLUSIONS: At five years, there was no difference in the performance of pin-retained amalgam restorations and bonded amalgam restorations. This study will be continued for at least a sixth year. CLINICAL IMPLICATIONS: Bonding with a filled, 4-META-based bonding resin appears to be a satisfactory method of retaining large amalgam restorations replacing cusps.

Support of undermined occlusal enamel provided by restorative materials.

OBJECTIVE: The purpose of this study was to test the support of occlusal enamel by amalgam (Dispersalloy), bonded amalgam (AmalgamBond Plus adhesive system with high-performance additive powder and Dispersalloy amalgam), and a bonded resin composite (Scotchbond Multi-Purpose adhesive system and Z100 resin composite). METHOD AND MATERIALS: For each material, 16 human molars were prepared. The lingual cusps were removed, and the dentin supporting the facial cusps was cut away, leaving a shell of enamel. Each group of prepared teeth was restored using the materials according to manufacturers' instructions. All specimens were thermocycled (1,500 cycles, 6 degrees C to 60 degrees C, dwell time 30 seconds), then mounted vertically in cast stone. A separating disk, mounted horizontally, was used to create a flat horizontal surface approximately 1.5 mm wide at the tips of both remaining enamel cusps of each specimen. Specimens were loaded evenly across the cusp tips at a crosshead speed of 10 mm/min until the fracture occurred. RESULTS: Data were analyzed using analysis of variance and Tukey A post hoc analysis. No significant difference was detected among amalgam, bonded amalgam, and bonded resin composite in their ability to support occlusal enamel. Support provided for occlusal enamel by the materials, whether bonded or not, was intermediate between no support and that provided by dentin. CONCLUSION: Without further development of materials technology and evidence of efficacy, restorative materials should not be relied upon to support undermined occlusal enamel.

Pain perception and utility: a comparison of the syringe and computerized local injection techniques.

Thirty patients received maxillary infiltration and mandibular inferior alveolar nerve block injections with both a traditional syringe and a computerized system, the Wand. Patients noted their preference for either system and rated their injection pain and postoperative discomfort on a ten-point scale for each type of injection. Mean injection discomfort ratings with the Wand were lower than with the syringe but were not statistically significant. Reduced postoperative discomfort using the Wand for the inferior alveolar nerve block was significant. Both of the dentists in the study and those patients who stated a preference favored the Wand system.

The evaluation of subatmospheric pressure and hyperbaric oxygen in ischemic full-thickness wound healing.

We evaluated the efficacy of subatmospheric pressure and hyperbaric oxygen (HBO) as adjuncts in the treatment of hypoxic full-thickness wounds in a rabbit model. We hypothesized that subatmospheric pressure and HBO independently are effective in improving wound healing in the ischemic wound model and that when they are used in combination there is an increased positive effect on wound healing. Using a standard ischemic wound model four full-thickness wounds were created on each ear of 41 male New Zealand white rabbits (N = 82 ears). On each rabbit one ear was dressed with the vacuum-assisted closure (VAC) device and connected to suction; the other was dressed identically without the suction and suction tubing. Twenty rabbits were treated with HBO daily for 10 days at 2.0 atmospheres absolute for 90 minutes plus descent and ascent times. Necropsy on all rabbits was performed on postoperative day 10. Four ischemic wound treatment groups were evaluated: Group 1 (N = 21) VAC dressing alone; Group 2 (N = 20) VAC dressing plus HBO; Group 3 (N = 21) VAC dressing to suction alone; and Group 4 (N = 20) VAC dressing to suction and HBO. Using light microscopy a veterinary pathologist blinded to treatment groups quantified peak granulation tissue, granulation tissue gap, and epithelialization tissue gap. Data were analyzed by analysis of variance with significance indicated by P < 0.05. Statistical significance was found in a comparison of VAC dressing to suction and VAC dressing alone for peak granulation tissue and granulation tissue gap both with and without use of HBO. VAC device use appears to increase the rate of healing in a rabbit ischemic wound model. HBO therapy did not significantly affect the rate of healing in this model.

Direct-placement gallium restorative alloy: a 3-year clinical evaluation.

OBJECTIVE: A pilot clinical study on a direct-placement gallium restorative alloy was initiated with nine patients who signed a consent form. METHOD AND MATERIALS: Thirty Class I restorations were placed and assessed over a 3-year period. The cavity preparations and surface of the restorations were sealed to prevent oral fluids from contacting the gallium alloy during placement and early setting of the gallium restorative material. RESULTS: The initial 18-month clinical results were encouraging. But at 21 months, one tooth had fractured, and within another year two molars were diagnosed with cracked-tooth syndrome (incomplete tooth fracture). These three fractured teeth were restored with amalgam and are symptomless at this time. There was little fracture at the margins of the gallium restorative, but tarnish and a rough surface were noted on many of the gallium restorations. The direct-placement gallium restorative alloys must be further assessed in the laboratory to correct dimensional instability. CONCLUSION: Results suggested that Galloy, used with either of two sealing resins, is not a suitable restorative material.

Evaluation of different methods for cleaning and preparing occlusal fissures.

The effectiveness of different methods for cleaning and preparing occlusal fissures before placing sealants was evaluated. Extracted mandibular molars received such treatments as brushing, pumicing, bur preparing, and air abrasion before application of fissure sealants. FluroShield fissure sealant was then applied to the occlusal fissures. Specimens were subjected to thermo-cycling and then immersed in a 10% solution of methylene blue, and finally sectioned. The sections were examined and photographed in a stereomicroscope, and the dye penetration was recorded using a scoring system. The results indicated that only the control (brushing with a dry brush) and the pumicing groups demonstrated dye penetration to the base of the sealant. Teeth prepared with the #1/4 round bur and air abrasion demonstrated a better seal in evaluated fissures. For this study, those three groups (occlusal fissures prepared with the #1/4 round bur and two air abrasion methods), demonstrated significantly better sealing (P < 0.01) than the control group and the other groups tested.

Air abrasion: an old technology reborn.

Recently, air abrasion has experienced a rebirth in restorative dentistry. Originally developed in the late 1940s, the principle of air abrasion is the imparting of kinetic energy to tiny aluminum oxide particles that are projected by a stream of compressed air or gas and expelled from a small nozzle. The force generated by the relatively hard particles striking a relatively hard surface is sufficient to cut into that surface. In the last decade, more than a dozen models of air abrasion units have been introduced into the marketplace and more are on the way. Manufacturers have developed air abrasion instruments that offer a broad range of features, from small table-top units to self-contained systems with compressors, vacuums, and curing lights. The costs range dramatically--from $1,000 to $20,000 or more--depending on the complexity of the features and attachments. Manufacturers make a variety of claims to support the value of this technology to the practicing dentist. A term often used to describe one of the benefits of air abrasion is microdentistry. The claim is that smaller, less invasive tooth preparations may be accomplished using air abrasion than with a traditional bur and air turbine. This may be true in some instances, but it would certainly depend on the operator's experience and ability to visually discern fine detail. Other claims about air abrasion are that it can be used to cut into tooth structure without local anesthesia and that it should be used on all stained grooves or fissures to determine if incipient carious lesions are present. Despite the limited number of clinical studies, the popularity of air abrasion continues to grow. To gain additional insight about these claims and to see what might be on the horizon for this technology, I spoke with three highly respected educators who are recognized for their expertise in air abrasion. What they said should give the reader a better understanding of how air abrasion might augment restorative dentistry procedures and techniques.

Amalgam at the new millennium.

Dental amalgam has served as an excellent and versatile restorative material for many years, despite periods of controversy. The authors review its history, summarize the evidence in regard to its performance and offer predictions for the future of this material. For the present, amalgam should remain the material of choice for economical direct restoration of posterior teeth. When esthetic concerns are paramount, tooth-colored materials, placed meticulously, can provide an acceptable alternative.

The effect of amalgam bonding on resistance form of Class II amalgam restorations.

OBJECTIVE: This study evaluated the load required to produce failure in Class II bonded amalgam restorations. METHOD AND MATERIALS: Five groups of 12 maxillary molars were mounted. Class II mesio-occlusal preparations were cut: group 1, extension through central grooves, without retention grooves; group 2, proximal slot preparation, without retention grooves; groups 3 and 5, slot preparation with long facial and lingual retention grooves; group 4, slot preparation without grooves, with unsupported proximal enamel allowed to remain. Groups 1 to 4 were restored with an amalgam-bonding system and amalgam; in group 5, no amalgam-bonding material was used. RESULTS: Mean (SD) failure loads: group 1, 281 (77) N; group 2, 246 (101) N; group 3, 238 (84) N; group 4, 254 (100) N; and group 5, 191 (66) N. CONCLUSION: Although there was a trend toward greater resistance to dislodgment or fracture when an amalgam-bonding technique was used, its use did not significantly increase the resistance to failure when compared to retention grooves alone.

Initial cervical exploration for parathyroidectomy is not benefited by preoperative localization studies.

Published data is controversial as to the ability of preoperative localization studies (PLS) to enhance the outcome of initial cervical exploration in patients with primary hyperparathyroidism (PHPT). One surgeon's experience was reviewed to compare surgical success, operative time, and morbidity of initial cervical exploration for PHPT in patients who had undergone PLS versus those who had not. From August 1991 to September 1997, 95 patients who had not undergone prior central cervical exploration presented for surgical management of PHPT. Sixty-seven patients underwent initial cervical exploration without any PLS having been performed (Group A). Twenty-eight patients underwent PLS, either alone or in combination, before surgical intervention (Group B). Analysis of intergroup variability was conducted upon the data available using a two-tailed t test for independent samples. In addition, the sensitivities and positive predictive values of the PLS were calculated using study reports and operative and histologic findings. There was no statistically significant difference in surgical success between those patients who had PLS and those that did not undergo PLS. Sixty-four of 67 patients (95.5%) not having PLS were cured with initial surgery, while 27 of 28 patients (96.4%) who had PLS were surgically cured. Mean postoperative calcium and intact parathormone levels were similar between the two groups, and the mean operative time did not differ. Permanent hypocalcemia occurred in one patient, and five patients had transient hoarseness. Thirty-six total PLS were obtained at an average cost of $752.68/patient, and seven patients underwent multiple tests. Overall, sestamibi scan had the highest positive predictive value (81%). For adenomatous disease alone, sestamibi scan was the most sensitive (83%). Our study shows that for matched groups limited to age, sex, and clinical diagnosis, the use of PLS did not shorten operative time, decrease complication frequency, nor alter the success of the operation as measured by postoperative calcium and parathormone levels. Therefore, routine use of preoperative localization studies before initial cervical exploration for PHPT cannot be recommended.

Extension for prevention: is it relevant today?

Extension for prevention has been an integral part of dentistry for over 100 years. Because this concept advocated the removal of sound tooth structure, it was not totally accepted at the turn of the century. The advent of the gold casting catapulted extension for prevention into general acceptance. In 1883, Webb presented a concept of "prevention of extension of decay". This concept advocated a proximal cavity preparation extending toward the buccal and lingual aspects of the tooth so that contact with adjacent teeth would not be at the margins. The separation of the margins, along with proper restoration contours, was thought to promote natural cleansing of the embrasures with saliva and fluids in the diet. GV Black's 1891 idea of "extension for prevention" was to provide extension of the preparation to the facial and lingual line angles in order to bring about "self-cleansing" margins via food excursion. Black's concept also included extending preparations through fissures to allow cavosurface margins to be on non-fissured enamel. Black integrated the extension of the proximal margins with his concept of an occlusal isthmus for a Class II amalgam preparation one-third the faciolingual width of the occlusal surface. Challenges to this concept of extension for prevention were immediate; and, by the 1950's, narrower, more conservative preparations were seen by a few as being more effective in preserving teeth. Not only occlusal width was reassessed, but the need to routinely extend proximal margins to the buccal and lingual line angles was also questioned. By the mid-1960's and early 1970's a more conservative approach to amalgam preparation was advocated and was being taught in some dental schools. Today, a standardized outline form should not be used or taught as a principle of cavity preparation. In areas where fissure caries has necessitated a preparation extending into dentin, a composite resin or dental amalgam restoration should be placed, and a fissure sealant should be used to protect remaining susceptible fissures from carious attack. This current form of the concept of extension for prevention, which is supported by clinical research, preserves sound tooth structure that, using outdated concepts, would have been cut away. Placing proximal margins in sound tooth structure that just clears an adjacent tooth is also strongly advocated. Sound enamel margins in certain areas may occasionally be left in contact with adjacent teeth for amalgam preparations. For Class II preparations for composite resin, facial or lingual proximal bevels will usually suffice to separate the margins from the adjacent tooth to allow finishing and polishing at the margins. Preventing unnecessary extension and allowing sounder tooth structure to remain is one important aspect of helping patients to maintain their teeth for their lifetimes.

Fracture resistance of complex amalgam restorations.

This study evaluated fracture resistance provided to complex amalgam restorations by adhesive and mechanical resistance features. The occlusal surfaces of 30 extracted molar teeth of similar size were ground flat to approximately 2 mm coronal to the CEJ. The teeth were divided into three groups. Roots were notched and embedded in acrylic resin. In two groups, four TMS Minim stainless steel pins were placed into dentin at the line angles. A copper band matrix was applied to each specimen and reinforced with compound. After applying either Copalite or Amalgambond Plus, Tytin amalgam was condensed into the matrix. The bands and excess amalgam were removed 10 minutes later, and each amalgam occlusal surface was ground flat to give the amalgam restoration a 4 mm occlusal height. Specimens were thermocycled for 2500 cycles at 6-60 degrees C with a 30-second dwell time. They were then stored in deionized water for 1 month at room temperature. A 1 mm 45 degrees bevel was placed on the facio-occlusal angle of the amalgam. Each specimen was loaded to failure in compression at 45 degrees in an Instron Testing Machine at a crosshead speed of 5 mm/min. The groups were: Group 1, four Minim pins and Copalite; Group 2, four Minim pins and Amalgambond Plus; and Group 3, Amalgambond Plus only. The data were analyzed using a one-factor ANOVA and a Tukey B post hoc test. There was no significant difference between Groups 1 and 3. The Amalgambond Plus combined with pins provided significantly greater resistance to fracture than pins or Amalgambond Plus alone (P < 0.05).