- Email: [email protected]
Maximum dose of local anesthetic
assessments quantified the numbers of Actinobacillus actinomycetemcomitans, Fusobacterium nucleatum spp, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola, and Tannerella forsythia and measured total bacterial count (TBC). Results.—TBC was markedly reduced after 1 day for both groups. The QRP group had slight changes in the median TBC values over 4 weeks, whereas the FMRP group had an increase in the median TBC values from the first day until the 4-week evaluation. The median TBC values were essentially the same between the 4- and 24-week assessments. The differences in microbiological status after 4 weeks and 24 weeks for the two groups were not statistically significant. The selected target bacteria showed no significant differences for the two methods either in the short-term or in the long-term. Discussion.—The microbiological outcomes after the two treatments were comparable. None of the target
bacteria were managed more effectively by one or the other of the two approaches.
Clinical Significance.—Full mouth scaling and root-planing has been suggested to prevent recontamination of previously debrided areas. No such benefit for the one-visit protocol was demonstrated in this study.
Jervøe-Storm P-M, Al Ahdab H, Semaan E, et al: Microbiological outcomes of quadrant versus full-mouth root planing as monitored by real-time PCR. J Clin Periodontol 34:156-163, 2007 Reprints available from P-M Jervøe-Storm, Department of Periodontology, Operative and Preventive Dentistry, University of Bonn, Welschnonnenstraße 17, 53113, Bonn, Germany; e-mail: [email protected]
Pharmacology Maximum dose of local anesthetic Background.—Body weight and physical condition form the basis for calculating the maximum safe dose of anesthesia for individuals. Although most current dosage guidelines are based mainly on weight, calculations based on body surface area may be more accurate. The determination of safe anesthesia doses for individuals was analyzed. Patient Factors.—Obese patients are more effectively judged on the basis of ideal body weight, since fat is poorly perfused with blood and therefore does not participate as a drug reservoir. Patients who are severely underweight, starving, bulimic, or debilitated usually have low circulating plasma protein levels. Diminished protein binding may cause unusually high blood levels of free, unbound drug that can result in overdose toxicity. The reduced mass of skeletal muscle tissue may not provide a sufficient temporary reservoir for circulating local anesthetic molecules. Then higher levels of circulating local anesthetic molecules can perfuse vital organs and produce a toxic reaction. The maximum weight-based dose for such patients must be lowered to prevent this development. Signs of toxicity can occur within a few minutes of receiving the dental injections, depending on the injection site, the tissue vascularity, and the presence or absence of a vasoconstrictor.
Table 1.—Maximum Limit for Lidocaine with Epinephrine for Healthy 3-Year-Old Child Weighing 33 Pounds / / /
/ /
/
2% Lidocaine/epi MRD range = 4.4 to 7 mg/Kg 33 lbs O 2.2 lbs/Kg = 15 Kg body weight 15 Kg x’s 7 mg/Kg = 105 rng maximum dose lido/ epi (liberal limit) or 15 Kg x’s 4.4 mg/Kg = 66 mg maximum dose lido/epi (conservative limit) 2% lido/epi = 36 mg lido/cart x’s 3 cartridges = 108 mg (liberal max = Less than 3 cartridges) 2% lido/epi = 36 mg lido/cart x’s 2 cartridges = 72 mg (conservative max = Less than 2 cartridges)
(Courtesy of Weaver JM: Calculating the maximum recommended dose of local anesthetic. Calif Dent Assoc J 35:61-63, 2007.)
Patients with significant cardiovascular disorders or those taking nonspecific beta-adrenergic–blocking drugs such as propranolol can develop an adverse reaction with epinephrine. In these cases the maximum safe volume of anesthetic is limited by the dose of epinephrine rather than the local anesthetic dose itself. Such medically compromised patients should receive no more than 40 mg of
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epinephrine. This can be delivered as 2.2 cartridges of 1:100,000 epinephrine or 4.4 cartridges of 1:200,000 epinephrine. Drug and Practitioner Factors.—Local anesthetics each have a maximum recommended dose. Patients who receive a combination of two local anesthetics may experience toxicity because the effects of each drug are additive. The recommendations for such situations reflect how conservatively the practitioner wishes to make the maximum recommended dose calculation. Solo practitioners in an office in a remote location may choose a more conservative dose than practitioners based in hospitals in an operating room or those who work with dental anesthesiologists, monitors, equipment, and advanced emergency medications. Dosages.—To calculate the dose limit for an individual patient, body weight in pounds is converted to kilograms by dividing pounds by 2.2 lb/kg (Table 1). Little research addresses how long after giving the maximum recommended dose a dentist can administer more. The scientific data are
insufficient on this point. A conservative approach limits the dosage to the maximum recommended dose given once a day.
Clinical Significance.—Calculating maximum dose, in addition to the math, must include consideration of whether the patient is obese or emaciated, injection site, cardiovascular status, and medications being taken. Dentists typically practice in a solitary setting. Erring on the conservative side is a wise practice.
Weaver JM: Calculating the maximum recommended dose of local anesthetic. Calif Dent Assoc J 35:61-63, 2007 Reprints available from JM Weaver, The Ohio State Univ, College of Dentistry, Section of Oral and Maxillofacial Surgery, Pathology and Anesthesiology, 305 W 12th Avenue, Columbus, OH 43218
Preventive Dentistry Soft drink acidity and enamel dissolution Background.—Most people consider soft drinks to be harmless even though it has been shown that their principal nutritive element is sugar. Consuming diet drinks assuages fears of too much sugar intake, but both sugared and nonsugared drinks have pH values less than 3.5 and contain phosphoric acid and/or citric acid, both of which contribute to dental erosion. Exposing enamel to soft drinks even for short time periods diminishes enamel microhardness. The relationship between the pH of 20 popular soft drinks and the effect on enamel loss was investigated. Methods.—The 20 drinks included nine cola beverages, eight noncola beverages, two iced teas, and one root beer (Table). Both sugared and unsugared varieties of the drinks were tested. The pH of each drink was measured immediately after opening the can, and the pH of tap water was measured immediately after collection. Two hundred fifty-
300
Dental Abstracts
two slices from the buccal and lingual surfaces of freshly extracted teeth were stored in distilled water until they were divided into 21 groups of 12 each and immersed in the various beverages or tap water. The slices were weighed before immersion, then removed from immersion after 6 hours, dried, and weighed again. This process was repeated after 24 hours and after 48 hours. Results.—The pH values of the noncola drinks were significantly higher than those of the cola drinks. The sugared cola and noncola drinks had lower pH values than the nonsugared versions. The lowest pH was found for RC Cola (2.39) and the highest was found for Mug Root Beer (4.04), with tap water having a pH of 7.67. The mean percent of weight loss in the enamel slices increased with longer immersion times, so the greatest loss of weight occurred after 48 hours of immersion. The highest mean percent of weight loss was with Surge (7.85%) and the
bacteria were managed more effectively by one or the other of the two approaches.
Clinical Significance.—Full mouth scaling and root-planing has been suggested to prevent recontamination of previously debrided areas. No such benefit for the one-visit protocol was demonstrated in this study.
Jervøe-Storm P-M, Al Ahdab H, Semaan E, et al: Microbiological outcomes of quadrant versus full-mouth root planing as monitored by real-time PCR. J Clin Periodontol 34:156-163, 2007 Reprints available from P-M Jervøe-Storm, Department of Periodontology, Operative and Preventive Dentistry, University of Bonn, Welschnonnenstraße 17, 53113, Bonn, Germany; e-mail: [email protected]
Pharmacology Maximum dose of local anesthetic Background.—Body weight and physical condition form the basis for calculating the maximum safe dose of anesthesia for individuals. Although most current dosage guidelines are based mainly on weight, calculations based on body surface area may be more accurate. The determination of safe anesthesia doses for individuals was analyzed. Patient Factors.—Obese patients are more effectively judged on the basis of ideal body weight, since fat is poorly perfused with blood and therefore does not participate as a drug reservoir. Patients who are severely underweight, starving, bulimic, or debilitated usually have low circulating plasma protein levels. Diminished protein binding may cause unusually high blood levels of free, unbound drug that can result in overdose toxicity. The reduced mass of skeletal muscle tissue may not provide a sufficient temporary reservoir for circulating local anesthetic molecules. Then higher levels of circulating local anesthetic molecules can perfuse vital organs and produce a toxic reaction. The maximum weight-based dose for such patients must be lowered to prevent this development. Signs of toxicity can occur within a few minutes of receiving the dental injections, depending on the injection site, the tissue vascularity, and the presence or absence of a vasoconstrictor.
Table 1.—Maximum Limit for Lidocaine with Epinephrine for Healthy 3-Year-Old Child Weighing 33 Pounds / / /
/ /
/
2% Lidocaine/epi MRD range = 4.4 to 7 mg/Kg 33 lbs O 2.2 lbs/Kg = 15 Kg body weight 15 Kg x’s 7 mg/Kg = 105 rng maximum dose lido/ epi (liberal limit) or 15 Kg x’s 4.4 mg/Kg = 66 mg maximum dose lido/epi (conservative limit) 2% lido/epi = 36 mg lido/cart x’s 3 cartridges = 108 mg (liberal max = Less than 3 cartridges) 2% lido/epi = 36 mg lido/cart x’s 2 cartridges = 72 mg (conservative max = Less than 2 cartridges)
(Courtesy of Weaver JM: Calculating the maximum recommended dose of local anesthetic. Calif Dent Assoc J 35:61-63, 2007.)
Patients with significant cardiovascular disorders or those taking nonspecific beta-adrenergic–blocking drugs such as propranolol can develop an adverse reaction with epinephrine. In these cases the maximum safe volume of anesthetic is limited by the dose of epinephrine rather than the local anesthetic dose itself. Such medically compromised patients should receive no more than 40 mg of
Volume 52
Issue 5
2007
299
epinephrine. This can be delivered as 2.2 cartridges of 1:100,000 epinephrine or 4.4 cartridges of 1:200,000 epinephrine. Drug and Practitioner Factors.—Local anesthetics each have a maximum recommended dose. Patients who receive a combination of two local anesthetics may experience toxicity because the effects of each drug are additive. The recommendations for such situations reflect how conservatively the practitioner wishes to make the maximum recommended dose calculation. Solo practitioners in an office in a remote location may choose a more conservative dose than practitioners based in hospitals in an operating room or those who work with dental anesthesiologists, monitors, equipment, and advanced emergency medications. Dosages.—To calculate the dose limit for an individual patient, body weight in pounds is converted to kilograms by dividing pounds by 2.2 lb/kg (Table 1). Little research addresses how long after giving the maximum recommended dose a dentist can administer more. The scientific data are
insufficient on this point. A conservative approach limits the dosage to the maximum recommended dose given once a day.
Clinical Significance.—Calculating maximum dose, in addition to the math, must include consideration of whether the patient is obese or emaciated, injection site, cardiovascular status, and medications being taken. Dentists typically practice in a solitary setting. Erring on the conservative side is a wise practice.
Weaver JM: Calculating the maximum recommended dose of local anesthetic. Calif Dent Assoc J 35:61-63, 2007 Reprints available from JM Weaver, The Ohio State Univ, College of Dentistry, Section of Oral and Maxillofacial Surgery, Pathology and Anesthesiology, 305 W 12th Avenue, Columbus, OH 43218
Preventive Dentistry Soft drink acidity and enamel dissolution Background.—Most people consider soft drinks to be harmless even though it has been shown that their principal nutritive element is sugar. Consuming diet drinks assuages fears of too much sugar intake, but both sugared and nonsugared drinks have pH values less than 3.5 and contain phosphoric acid and/or citric acid, both of which contribute to dental erosion. Exposing enamel to soft drinks even for short time periods diminishes enamel microhardness. The relationship between the pH of 20 popular soft drinks and the effect on enamel loss was investigated. Methods.—The 20 drinks included nine cola beverages, eight noncola beverages, two iced teas, and one root beer (Table). Both sugared and unsugared varieties of the drinks were tested. The pH of each drink was measured immediately after opening the can, and the pH of tap water was measured immediately after collection. Two hundred fifty-
300
Dental Abstracts
two slices from the buccal and lingual surfaces of freshly extracted teeth were stored in distilled water until they were divided into 21 groups of 12 each and immersed in the various beverages or tap water. The slices were weighed before immersion, then removed from immersion after 6 hours, dried, and weighed again. This process was repeated after 24 hours and after 48 hours. Results.—The pH values of the noncola drinks were significantly higher than those of the cola drinks. The sugared cola and noncola drinks had lower pH values than the nonsugared versions. The lowest pH was found for RC Cola (2.39) and the highest was found for Mug Root Beer (4.04), with tap water having a pH of 7.67. The mean percent of weight loss in the enamel slices increased with longer immersion times, so the greatest loss of weight occurred after 48 hours of immersion. The highest mean percent of weight loss was with Surge (7.85%) and the