- Email: [email protected]
Lycopene
irritation that adversely affects feeding; if they produce persistent lingual ulceration that does not respond to conservative approaches; or if they are supernumerary natal teeth confirmed radiographically. If none of these conditions is present, the teeth are retained; those surviving for 4 months have a good prognosis for retention. Riga-Fede disease does not absolutely indicate the need for extraction. Lingual ulceration may be managed with smoothing or placing an adhesive restoration to buffer the sharp incisal edges. Enamel hypomineralization and hypoplasia are common and can complicate bonding and increase the risk of aspiration. Anterior crowding may result from early extraction.
Clinical Significance.—It is important to consider natal teeth as a variant of normal development. It is also necessary to acknowledge the cultural and social attitudes toward this
aberration. This may require reassuring parents and protecting children from unneeded extraction. The child’s best interests must be balanced against cultural influences. Careful clinical evaluation and treatment planning should be combined with parental counseling and awareness to reduce anxiety and counteract myths associated with this unusual and relatively infrequent development.
Sothinathan R, Shakib K: Natal teeth: A sign of fortuity or grave misfortune. Br Dent J 210:265-266, 2011 Reprints available from K Shakib, Dept of Maxillofacial Surgery, Northwick Park Hosp, Watford Rd, Middlesex, HA1 3UJ; e-mail: [email protected]
Oral Cancer Lycopene Background.—Oral malignancy ranks twelfth among all cancers and has a mortality as high as 50%, with no significant improvements over the past 30 years. Oral cancer’s etiology is multifactorial, with genetic, environmental, viral, social, and behavioral effects implicated. Diet and nutrition play an important preventive role that is being scrutinized increasingly. A diet rich in fruits and vegetables is likely beneficial in preventing oral malignancy. Lycopene is a carotenoid found in tomatoes and other fruits and vegetables that may alleviate chronic diseases such as cancers and cardiovascular disease. The potential significance of lycopene in the development, prevention, and treatment of oral premalignant lesions and oral cancer was investigated. Structure and Properties.—Lycopene is an acyclic isomer of b-carotene and a highly unsaturated hydrocarbon that contains 11 conjugated and two unconjugated double bonds. This allows it to exist in both cis- and trans-isomeric forms. In plants, it exists predominantly in an all trans-isomeric form, but light, thermal energy, and chemical reactions can induce it to form cis-trans isomers. Lycopene is a highly stable molecule but can undergo oxidative thermal degradation and photodegradation. Humans cannot synthesize lycopene, so it must be obtained from the diet. Several biological and lifestyle factors affect lycopene levels in humans, with better absorption from heat-processed food sources and lipid-rich diets
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Dental Abstracts
than from raw food. Lycopene is the predominant carotenoid in human plasma. When ingested, lycopene appears first in plasma, initially in the very-low-density lipoprotein and chylomicron fractions, then later in low-density lipoprotein and high-density lipoprotein fractions. Lycopene is also distributed in various tissues, especially the adrenal gland, liver, prostate gland, and testes. Preventive Effects Against Cancer.—Lycopene’s bioavailability remains to be proved, but its biologic effects are attributed to mechanisms other than vitamin A. The two major hypotheses for its mechanisms of action are (1) that it protects against oxidative stress by quenching single oxygen and scavenging free radicals and (2) that its oxygen-quenching ability protects against DNA oxidative damage, preventing potential mutation that may be related to the transformation into cancer cells (Fig 2). Lycopene may have an important role as the first line of defense against oxidative stress. Lycopene may also increase gapjunction communication (GJC), regulate gene function, augment antiproliferation and prodifferentiation activities, induce apoptosis, and modulate carcinogen-metabolizing enzymes and immune function. Deficient GJC is related to many human tumors. Restoration or upregulation of GJC is related to a diminished proliferation of tumor cells. Lycopene can suppress the carcinogen-induced phosphorylation of several regulatory proteins. Cancer cells can no longer regulate the cell cycle, especially at the first gap
Fig 2.—The biologic effects of lycopene in preventing oral and other cancers. Lycopene, which is from various fruits and vegetables, may have two major kinds of biologic effects: antioxidative effects and nonoxidative mechanisms. Acting as potent antioxidants, lycopene may inactivate free radicals and attenuate free radicalsinitiated oxidative reactions, particularly lipid peroxidation and DNA oxidative damage, thereby preventing tissue damage as well as potential cancerization. Alternatively, lycopene may also exert its bioavailabilities through other nonoxidative effects, such as regulation of gap-junction communication, gene function regulation, hormone and immune modulation, and antiproliferation and prodifferentiation activities. These mechanisms may be interrelated or operate simultaneously to reduce risk for various types of cancers, as well as oral precancerous lesions and cancer, thus providing health benefits. (Courtesy of Lu R, Dan H, Wu R, et al: Lycopene: Features and potential significance in the oral cancer and precancerous lesions. J Oral Pathol Med 40:361-368, 2011.)
phase, and therefore cannot control their proliferation rate. Lycopene inhibits early phases of the cell cycle in various cancer cells, inhibits the proliferation of various types of cancer cells, and induces cell differentiation. Damaged cells that fail to undergo apoptosis can become immortal and transform into malignant cells. Lycopene promotes apoptosis and might serve as a chemotherapeutic agent. It significantly induces cytochrome P450-dependent enzyme, phase I enzymes in a dose-dependent manner, and the phase II enzyme hepatic quinine reductase twofold. These enzymes function to remove foreign substances and carcinogens from the body. Lycopene may also regulate intrathymic T-cell differentiation, suppressing tumor growth. Preventive Effects Against Premalignant Oral Lesions.—Oral submucous fibrosis (OSF) is characterized by progressive fibrosis of the oral mucosa, causing symptoms such as burning mouth, intolerance to spicy foods, xerostomia, and limited mouth opening. This premalignant condition has a high potential for malignant transformation. Lycopene was found to improve mouth opening and reduce burning mouth sensation more effectively than placebo and caused no side effects. Therefore, it may prove to be efficacious, safe, and reliable for the treatment of OSF through its ability to inhibit abnormal fibroblasts, upregulate lymphocyte resistance to stress, and suppress the inflammatory response. Leukoplakia is a white patch or plaque that is the most common precancerous oral lesion and has a recognized risk
for malignant transformation. Tobacco use is associated with leukoplakia. Effective treatment must include cessation of tobacco use plus antioxidants. Improved micronutrient levels of lycopene and b-carotene may protect against the risk of oral leukoplakia. Tomato consumption, which is the primary source for lycopene, is the most protective dietary factor against leukoplakia. Preventive and Therapeutic Effects Against Oral Cancer.—Free radicals have been implicated in the development of oral cancer. Elevated levels have been found consistently in the serum, saliva, and blood leukocytes of patients with oral cancer. Antioxidants such as lycopene may reduce the risk of developing oral cancer through an anticarcinogenic effect. Cell-cell interaction via GJC is a key factor in tissue homeostasis, and alterations are associated with neoplasia. It is possible that lycopene can suppress the proliferation and promote the GJC of oral cancer cells. This effect is exerted through various mechanisms, including modulation of lipid peroxidation, enhanced antioxidant presence in target organs, and suppression of cell proliferation. Discussion.—Preliminary human clinical trials demonstrate that lycopene has a potential therapeutic role in precancerous lesions such as OSF and oral leukoplakia. It is also a promising anticarcinogenic agent against oral cancer. However, some problems remain. It is unclear whether reductions in disease risk result from ingesting whole tomatoes or lycopene alone. The mechanisms involved in
Volume 57
Issue 2
2012
103
lycopene’s therapeutic effects against oral diseases remain unclear. Also, the numbers and sample sizes of present studies are too limited to provide conclusive evidence that lycopene intake reduces oral disease risk.
Clinical Significance.—Many studies suggest that lycopene may have beneficial effects in the management of certain premalignant lesions of the oral cavity and may prove helpful against oral cancers, along with other treatments. Further studies with more patients are needed to confirm these suggestions before
lycopene can be recommended as routine prevention or treatment for these diseases.
Lu R, Dan H, Wu R, et al: Lycopene: Features and potential significance in the oral cancer and precancerous lesions. J Oral Pathol Med 40:361-368, 2011 Reprints available from Q Chen, State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan Univ, No 14, Sect 3, Renminnan Rd, Chengdu 610041, China; fax: þ86 28 85405251; e-mail: [email protected]
Orofacial Trauma Childhood dental trauma Background.—Traumatic dental injuries in children are common, with 30% sustaining injuries to primary dentition and 22% to permanent dentition. These injuries can damage the pulp and periodontal ligament and lead to the loss of the tooth. Management of traumatized teeth should begin immediately, especially if avulsed permanent teeth are involved, with the best results attending replantation within 30 minutes of avulsion. Most of these injuries occur at home or school, with first aid rendered by parents, teachers, or coaches. The level of knowledge of elementary school teachers regarding traumatic dental injuries to permanent teeth and their appropriate emergency management, their source of information, and their need for more education in this area were evaluated. Methods.—Two hundred forty questionnaires were distributed to teachers in 12 elementary schools in the Tel-Aviv area. These consisted of one part with questions on demographics (gender, age, teaching experience, first aid training, and dental trauma experience); a second part with multiple-choice questions on attitude and source of knowledge (self-assessed); and a third part with multiple-choice questions about managing traumatically injured teeth. The third part was scored, with teachers receiving a grade from 1 to 10. Results.—One hundred sixty-four teachers (68%) responded. Only 6 of the 126 teachers who remembered receiving first aid training during their teaching studies said that dental injuries were covered. Additional first aid training was obtained in the army and other sources by 28.7% of respondents, but only 3% of these claimed it included dental first aid. Dental trauma experience was reported by 44%
104
Dental Abstracts
of teachers, and 15.9% of teachers took part with their students in dental health projects. Of the 106 teachers who reported no or little knowledge of dental trauma, only 69 (42.2%) were interested in learning more. Half of the teachers reported complete or moderate satisfaction with their level of knowledge. Self-assessed knowledge and knowledge score were correlated, as were satisfaction with self-assessed knowledge and knowledge score. Dentists were the source of information for most teachers, with just five teachers taking a formal course. Two teachers reported no information about dental trauma. The average score for all respondents was 4.59 of the possible 10 points. Significantly higher scores were logged for teachers who were parents, who had previous experience with trauma, and who were age 35 to 49 years. Discussion.—The level of knowledge of these teachers regarding dental trauma is inadequate for delivering appropriate care to children suffering these injuries. Teacher training should include this topic in its curriculum, and knowledge should be reinforced and updated through periodic in-service training courses.
Clinical Significance.—Elementary school teachers should have knowledge regarding traumatic dental injuries and the first aid treatment
Clinical Significance.—It is important to consider natal teeth as a variant of normal development. It is also necessary to acknowledge the cultural and social attitudes toward this
aberration. This may require reassuring parents and protecting children from unneeded extraction. The child’s best interests must be balanced against cultural influences. Careful clinical evaluation and treatment planning should be combined with parental counseling and awareness to reduce anxiety and counteract myths associated with this unusual and relatively infrequent development.
Sothinathan R, Shakib K: Natal teeth: A sign of fortuity or grave misfortune. Br Dent J 210:265-266, 2011 Reprints available from K Shakib, Dept of Maxillofacial Surgery, Northwick Park Hosp, Watford Rd, Middlesex, HA1 3UJ; e-mail: [email protected]
Oral Cancer Lycopene Background.—Oral malignancy ranks twelfth among all cancers and has a mortality as high as 50%, with no significant improvements over the past 30 years. Oral cancer’s etiology is multifactorial, with genetic, environmental, viral, social, and behavioral effects implicated. Diet and nutrition play an important preventive role that is being scrutinized increasingly. A diet rich in fruits and vegetables is likely beneficial in preventing oral malignancy. Lycopene is a carotenoid found in tomatoes and other fruits and vegetables that may alleviate chronic diseases such as cancers and cardiovascular disease. The potential significance of lycopene in the development, prevention, and treatment of oral premalignant lesions and oral cancer was investigated. Structure and Properties.—Lycopene is an acyclic isomer of b-carotene and a highly unsaturated hydrocarbon that contains 11 conjugated and two unconjugated double bonds. This allows it to exist in both cis- and trans-isomeric forms. In plants, it exists predominantly in an all trans-isomeric form, but light, thermal energy, and chemical reactions can induce it to form cis-trans isomers. Lycopene is a highly stable molecule but can undergo oxidative thermal degradation and photodegradation. Humans cannot synthesize lycopene, so it must be obtained from the diet. Several biological and lifestyle factors affect lycopene levels in humans, with better absorption from heat-processed food sources and lipid-rich diets
102
Dental Abstracts
than from raw food. Lycopene is the predominant carotenoid in human plasma. When ingested, lycopene appears first in plasma, initially in the very-low-density lipoprotein and chylomicron fractions, then later in low-density lipoprotein and high-density lipoprotein fractions. Lycopene is also distributed in various tissues, especially the adrenal gland, liver, prostate gland, and testes. Preventive Effects Against Cancer.—Lycopene’s bioavailability remains to be proved, but its biologic effects are attributed to mechanisms other than vitamin A. The two major hypotheses for its mechanisms of action are (1) that it protects against oxidative stress by quenching single oxygen and scavenging free radicals and (2) that its oxygen-quenching ability protects against DNA oxidative damage, preventing potential mutation that may be related to the transformation into cancer cells (Fig 2). Lycopene may have an important role as the first line of defense against oxidative stress. Lycopene may also increase gapjunction communication (GJC), regulate gene function, augment antiproliferation and prodifferentiation activities, induce apoptosis, and modulate carcinogen-metabolizing enzymes and immune function. Deficient GJC is related to many human tumors. Restoration or upregulation of GJC is related to a diminished proliferation of tumor cells. Lycopene can suppress the carcinogen-induced phosphorylation of several regulatory proteins. Cancer cells can no longer regulate the cell cycle, especially at the first gap
Fig 2.—The biologic effects of lycopene in preventing oral and other cancers. Lycopene, which is from various fruits and vegetables, may have two major kinds of biologic effects: antioxidative effects and nonoxidative mechanisms. Acting as potent antioxidants, lycopene may inactivate free radicals and attenuate free radicalsinitiated oxidative reactions, particularly lipid peroxidation and DNA oxidative damage, thereby preventing tissue damage as well as potential cancerization. Alternatively, lycopene may also exert its bioavailabilities through other nonoxidative effects, such as regulation of gap-junction communication, gene function regulation, hormone and immune modulation, and antiproliferation and prodifferentiation activities. These mechanisms may be interrelated or operate simultaneously to reduce risk for various types of cancers, as well as oral precancerous lesions and cancer, thus providing health benefits. (Courtesy of Lu R, Dan H, Wu R, et al: Lycopene: Features and potential significance in the oral cancer and precancerous lesions. J Oral Pathol Med 40:361-368, 2011.)
phase, and therefore cannot control their proliferation rate. Lycopene inhibits early phases of the cell cycle in various cancer cells, inhibits the proliferation of various types of cancer cells, and induces cell differentiation. Damaged cells that fail to undergo apoptosis can become immortal and transform into malignant cells. Lycopene promotes apoptosis and might serve as a chemotherapeutic agent. It significantly induces cytochrome P450-dependent enzyme, phase I enzymes in a dose-dependent manner, and the phase II enzyme hepatic quinine reductase twofold. These enzymes function to remove foreign substances and carcinogens from the body. Lycopene may also regulate intrathymic T-cell differentiation, suppressing tumor growth. Preventive Effects Against Premalignant Oral Lesions.—Oral submucous fibrosis (OSF) is characterized by progressive fibrosis of the oral mucosa, causing symptoms such as burning mouth, intolerance to spicy foods, xerostomia, and limited mouth opening. This premalignant condition has a high potential for malignant transformation. Lycopene was found to improve mouth opening and reduce burning mouth sensation more effectively than placebo and caused no side effects. Therefore, it may prove to be efficacious, safe, and reliable for the treatment of OSF through its ability to inhibit abnormal fibroblasts, upregulate lymphocyte resistance to stress, and suppress the inflammatory response. Leukoplakia is a white patch or plaque that is the most common precancerous oral lesion and has a recognized risk
for malignant transformation. Tobacco use is associated with leukoplakia. Effective treatment must include cessation of tobacco use plus antioxidants. Improved micronutrient levels of lycopene and b-carotene may protect against the risk of oral leukoplakia. Tomato consumption, which is the primary source for lycopene, is the most protective dietary factor against leukoplakia. Preventive and Therapeutic Effects Against Oral Cancer.—Free radicals have been implicated in the development of oral cancer. Elevated levels have been found consistently in the serum, saliva, and blood leukocytes of patients with oral cancer. Antioxidants such as lycopene may reduce the risk of developing oral cancer through an anticarcinogenic effect. Cell-cell interaction via GJC is a key factor in tissue homeostasis, and alterations are associated with neoplasia. It is possible that lycopene can suppress the proliferation and promote the GJC of oral cancer cells. This effect is exerted through various mechanisms, including modulation of lipid peroxidation, enhanced antioxidant presence in target organs, and suppression of cell proliferation. Discussion.—Preliminary human clinical trials demonstrate that lycopene has a potential therapeutic role in precancerous lesions such as OSF and oral leukoplakia. It is also a promising anticarcinogenic agent against oral cancer. However, some problems remain. It is unclear whether reductions in disease risk result from ingesting whole tomatoes or lycopene alone. The mechanisms involved in
Volume 57
Issue 2
2012
103
lycopene’s therapeutic effects against oral diseases remain unclear. Also, the numbers and sample sizes of present studies are too limited to provide conclusive evidence that lycopene intake reduces oral disease risk.
Clinical Significance.—Many studies suggest that lycopene may have beneficial effects in the management of certain premalignant lesions of the oral cavity and may prove helpful against oral cancers, along with other treatments. Further studies with more patients are needed to confirm these suggestions before
lycopene can be recommended as routine prevention or treatment for these diseases.
Lu R, Dan H, Wu R, et al: Lycopene: Features and potential significance in the oral cancer and precancerous lesions. J Oral Pathol Med 40:361-368, 2011 Reprints available from Q Chen, State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan Univ, No 14, Sect 3, Renminnan Rd, Chengdu 610041, China; fax: þ86 28 85405251; e-mail: [email protected]
Orofacial Trauma Childhood dental trauma Background.—Traumatic dental injuries in children are common, with 30% sustaining injuries to primary dentition and 22% to permanent dentition. These injuries can damage the pulp and periodontal ligament and lead to the loss of the tooth. Management of traumatized teeth should begin immediately, especially if avulsed permanent teeth are involved, with the best results attending replantation within 30 minutes of avulsion. Most of these injuries occur at home or school, with first aid rendered by parents, teachers, or coaches. The level of knowledge of elementary school teachers regarding traumatic dental injuries to permanent teeth and their appropriate emergency management, their source of information, and their need for more education in this area were evaluated. Methods.—Two hundred forty questionnaires were distributed to teachers in 12 elementary schools in the Tel-Aviv area. These consisted of one part with questions on demographics (gender, age, teaching experience, first aid training, and dental trauma experience); a second part with multiple-choice questions on attitude and source of knowledge (self-assessed); and a third part with multiple-choice questions about managing traumatically injured teeth. The third part was scored, with teachers receiving a grade from 1 to 10. Results.—One hundred sixty-four teachers (68%) responded. Only 6 of the 126 teachers who remembered receiving first aid training during their teaching studies said that dental injuries were covered. Additional first aid training was obtained in the army and other sources by 28.7% of respondents, but only 3% of these claimed it included dental first aid. Dental trauma experience was reported by 44%
104
Dental Abstracts
of teachers, and 15.9% of teachers took part with their students in dental health projects. Of the 106 teachers who reported no or little knowledge of dental trauma, only 69 (42.2%) were interested in learning more. Half of the teachers reported complete or moderate satisfaction with their level of knowledge. Self-assessed knowledge and knowledge score were correlated, as were satisfaction with self-assessed knowledge and knowledge score. Dentists were the source of information for most teachers, with just five teachers taking a formal course. Two teachers reported no information about dental trauma. The average score for all respondents was 4.59 of the possible 10 points. Significantly higher scores were logged for teachers who were parents, who had previous experience with trauma, and who were age 35 to 49 years. Discussion.—The level of knowledge of these teachers regarding dental trauma is inadequate for delivering appropriate care to children suffering these injuries. Teacher training should include this topic in its curriculum, and knowledge should be reinforced and updated through periodic in-service training courses.
Clinical Significance.—Elementary school teachers should have knowledge regarding traumatic dental injuries and the first aid treatment