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Dental Tribune Middle East & African Edition

hygiene tribune Dental Tribune Middle East & Africa Edition | March-April 20156B > Page 8B Extrinsic tooth discoloration, an updated review By Dr. Kassis Cynthia DDS, DESCO, DUDRE, department of Esthetic and Restorative Dentistry – Saint Joseph Uni- versity Dr. Khoury Pierre DDS, DESS, department of Prostho- dontics – Lebanese University - Dr. Zogheib Tatiana, DDS, Oral Imaging Center, OMFS- IMPATH research group, Dept Imaging & Faculty of Medi- cine, University of Leuven and Oral & Maxillofacial Surgery, University Hospitals Leuven Prof. Mehanna Carina DDS, CESA, PhD, FICD, Director of Esthetic and Restorative Den- tistry Postgratuated Program Saint Joseph University, Presi- dent of the continuing Edu- cation committee - Lebanese Dental Association A bstract The appearance of the dentition is of concern to a large number of people seeking dental treatment and the color of the teeth is of particular cos- metic importance. Discolored teeth are seen frequently in the dental office and present a ma- jor challenge to dentists. The causes of tooth discoloration are varied and complex. Basi- cally, there are two types of tooth discolorations: those caused by extrinsic factors and those caused by intrinsic congenital or systemic influence. The ma- jority of tooth discolorations are extrinsic in nature and appear as brown integuments. Dental treatment of tooth discoloration involves identifying the etiology and implementing therapy. An overview of the extrinsic etiolo- gies and the clinical appearance of tooth discoloration are dis- cussed in this review. Key-words: Discoloration, stains, etiology, whitening, chro- mogenic product. Introduction Ever since the ancient times, mankind has been questing for beauty through the perfection of every detail. Ancient Romans, for example, used urine and goat milk in an attempt to whit- en their teeth. There has been a recent increase in interest in the treatment of tooth staining and discoloration as shown by the large number of tooth whit- ening agents appearing on the market.1 Teeth discolorations are asso- ciated with many clinical and esthetical challenges. They can have an impact on a person’s self-image and self-confidence in today’s society, where most people place tooth color high. The correct diagnosis of the cause of discoloration is impor- tant as it has a profound effect on treatment outcomes. Normal enamel is colorless and translucent, and the color of the dentin is mainly responsible for the color of the tooth. The den- tin influences more on the tooth color where it consists of thick layers and where the enamel layer is thin (cervical margins). A variety of colors can typically be seen in a tooth and from the gingival margin to the incisal edge of the tooth a gradation of the color occurs. Any changes of tooth structure is likely to cause an alteration in outward appearance of the tooth caused by changes of light transmit- ting and reflecting properties2 : Some discolorations are located on the outer surface of the tooth structure, others are caused by stain taken up by the enamel or dentin, and some occur dur- ing tooth development and re- sult in an alteration of the light transmitting properties of the tooth structures. Tooth discol- orations are caused by multiple factors: medications, genetic defects, diseases, trauma, caries and normal aging processes are some examples. It is important to understand what staining is in order to be able to prevent it. There are two types of tooth dis- coloration: extrinsic which af- fects teeth from the outside and intrinsic which affects the teeth from the inside. Extrinsic discoloration lies on the tooth surface or in the ac- quired pellicle. The majority of tooth discolorations are ex- trinsic in nature and appear as brown integuments. Extrinsic staining of a single tooth is unu- sual. The distribution is usually generalized. The stains are usu- ally found on surfaces with poor tooth brush accessibility. Smok- ing, tea or coffee consumption and increasing age are pro- moting factors and such dis- colorations are frequently seen in connection with oral use of antibacterial plaque-inhibiting mouthrinses. Chemical altera- tion of the acquired pellicle ap- pears to be the major reason for these brown integuments.3 The causes of extrinsic staining can be divided into two catego- ries; those compounds which are incorporated into the pellicle and produce a stain as a result of their basic color 2 and those which lead to staining caused by chemical interaction at the tooth surface.4 Direct staining has a multi-fac- torial etiology with chromogens derived from dietary sources or substances habitually placed in the mouth. These organic chro- mogens are taken up by the pel- licle and the colour imparted is determined by the natural col- our of the chromogen. The ori- gin of the stain may be metallic or non-metallic.5 6 The aim of this review is to sys- tematically search the literature for data concerning extrinsic tooth discoloration etiologies in order to establish the right treat- ment plan. 1 - Tobacco For ages, tobacco has been pop- ular and its use is significantly increasing in spite of alarming health hazards.7 Tobacco smoking and chew- ing (chewing of betel morsel: piper betel, Pan) are known to cause staining.8 Smoking leads to not only tobacco and nicotine stains on teeth (yellowed teeth) but it also leads to gum disease and oral cancer.9 There are all sorts of chemicals in cigarettes, including tobacco, nicotine and tar that could harm gum tissue cells, weakening it in the face of periodontal diseases and infec- tions. This is true of cigarettes, pipes, chewing tobacco, water- pipe and cigars to varying de- grees, all will cause bad breath, crippled teeth and ugly brown- ish-yellowish stains. Tobacco is rich with nicotine10,11 which is named after the tobacco plant Nicotiana tabacum.7 It is an in- herently colorless substance that turns yellow when put in contact with oxygen. When cigarette smoke is inhaled, the insides of the mouth is coating not only with tar from the tobacco smoke but with nicotine. Nicotine pene- trates the nooks and crannies of the teeth leading to teeth stains. Tobacco smoke contains carbon monoxide, thiocyanate, herbi- cide, fungicide and pesticide residues, tars, and many other substances which promote dis- eases and impair the body’s de- fense mechanism and functions. Toxic substances in the tobacco smoke affect virtually every vi- able cell type.7 A quantitative synthesis of the limited human data from 117 adults from Lebanon, Jordan, Kuwait, and India indicates that daily waterpipe use produces nicotine absorption of a magni- tude similar to that of daily use of cigarettes. This equivalence with cigarette use of about 10 cigarettes/day.10 Smoking cessation support in- terventions with an added stain removal or tooth whitening ef- fect may increase motivation to quit smoking. Oral health pro- fessionals are well placed to pro- vide smoking cessation advice and support to patients. A study evaluated the effect of a gum used in a smoking cessation program administered in a den- tal setting, on extrinsic stain and tooth shade among smokers. At week 6, the gum-group experi- enced a reduction in mean stain scores whilst the tablet-group experienced an increase. The change in mean tooth shade scores was statistically signifi- cantly greater in the gum-group than in the tablet group at 2, 6 and 12 weeks with greater light- ening in the gum-group at each examination period.12 2 - Dark Drinks From black coffee to red wine, food and beverages can cause the pearly whites to become el- lows.The foods that are most likely to stain or discolor teeth are: a - Black Coffee Although melanoidins from cof- fee possesses antioxidant capac- ity,13 deposition of tannins found in tea, coffee, and other bever- ages cause brown stains. The darker the coffee, the more it stains the teeth. Adding milk or cream will actually help. A study done by JZ Bazzi showed that toothbrushing resulted in a sig- nificantly reduced color change only for cigarette smoke–stained specimens and not for coffee stained teeth, which means that coffee stains teeth more indel- ibly than tobacco.14 According to Pirolo, the expo- sure to coffee after bleaching causes less color changes than the exposure to a cola-based soft drink regardless of the time after bleaching.15 A study evaluated the colour sta- bility of three laminate veneer materials with tea, coffee and cigarette. It was found that ciga- rette smoke was the most stain- ing agent.16 The aim of an in vitro study done by Mutlu-Sagesen et al was to compare the color stability of commercially available denture teeth materials.The filtered cof- fee solution was found to be more chromogenic than the tea, and cola staining solutions.17 b - Tea Tea, the commonly consumed beverage, is gaining increased attention in promoting overall health. In specific, green tea is considered a healthful bever- age due to the biological activ- ity of its polyphenols.18,19 There are three main varieties of tea - green, black, and oolong, all derived from the leaves of the C. sinensis plant. The difference between the various teas lies in their processing. Green tea is prepared from unfermented leaves, the oolong tea leaves are partially fermented and black tea is fully fermented.20 Lee R et al have shown that the addition of milk to tea signifi- cantly reduces the tea’s ability to stain teeth. Casein was de- termined to be the component of milk that is responsible for preventing tea-induced stain- ing of teeth to a similar order of magnitude that can be obtained by vital bleaching treatments.21 Bovine teeth were immersed for one week in a solution of tea, coffee or red fruits respectively. Tests showed that diode laser was effective only at bleaching teeth stained with coffee mean- while the KTP laser was efficient at bleaching teeth with coffee, tea and red fruits stain. This study suggests that a relation be- tween the laser wavelength and the type of staining on the dental enamel and the efficacy of the whitening treatment exists.22 In a work done by Young N et al of the basic interactions be- tween whitening agents and tea stain molecules, it was shown that the reaction rates between chromogens in the tea solution and hydrogen peroxide can be accelerated significantly using ferrous gluconate activator and blue light irradiation.23 As for all colored beverages, in order to minimize the stain- ing effect of tea, it can be drunk through a straw. c - Red Wine Red wine is packed with poly- phenols24 that help prevent periodontal diseases that dam- age the gums and bone around teeth.25, 26, 18 Nevertheless red wine causes tooth staining. In addition, the alcohol content is very acidic and wears away tooth enamel. A research aimed to investigate bleached enamel susceptibility to coffee and red-wine staining at different time periods after bleaching. No differences were observed between the exposure times of 30 and 150 min after bleaching for both beverages (p > 0.05). Although coffee did not stain the surface, red wine sig- nificantly darkened previously bleached enamel.27 Attia et al have quantified the change in color of human and bovine teeth exposed to a coffee solution during a 16% carba- mide peroxide (16% CP) home application bleaching treatment using photoreflectance analysis. When the teeth were exposed to a coffee solution during home bleaching treatment, the whit- ening effect was observed to be less stable (P < 0.05). Bovine and human enamel substrates behaved similarly in terms of staining and bleaching effects, although they presented inherent differences in color.28 A study has examined the sur- face staining mechanism of a photopolymerized composite by coffee, oolong tea, and red wine. Dental composite was subject- ed to an experimental 24-hour staining cycle: 17-hour immer- sion in artificial saliva solution containing 0.3% mucin followed by 7-hour immersion in coffee, tea, or wine. Wine caused the most severe staining, followed by tea and coffee. Chlorhexidine increased the staining effect of tea and coffee when compared to the control specimens. Com- mon drinks stained the dental composite, but each by a spe- cific mechanism that depended on external conditions such as the presence of chlorhexidine.29 Cortes et al have evaluated the influence of coffee and red wine staining on tooth color during and after bleaching. Blocks ob- tained from human molars were divided into 11 groups in accord- ance with the bleaching treat- ment-peroxide carbamide 10%, 15% or 20%- and in accordance with the stain therapy-coffee, wine or without staining (con- trol). During bleaching, remin- eralization of the enamel with artificial saliva and the subse- quent bleaching were effective in preventing enamel staining. After the whitening procedures, both stain therapies-coffee or non-metallic.56

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