KHAT CHEWING AND DENTAL STAINING
Dr Kassahun Hailu, DDS
Department of Restorative Dentistry
Howard University College of Dentistry
600 “W” Street N.W
Washington D.C 20059
Dr Davidson O. Lawoyin, DDS
Dr Dexter Woods, DDS
Director of AEGD
Dr John R. Bailey, DDS, MS
Khat has been in use for decades in many parts of the world particularly in the Middle East and East Africa. The potential to induce excitation and pleasure have made it very appealing among users. The staining effect however both extrinsically and particularly intrinsically have not been thoroughly understood. This is a case report of a 21 year old African male who presented to the Howard University College of Dentistry Clinic complaining of generalized discoloration. Subsequent examination and history revealed that the discoloration was due to chronic use of Khat. The importance of appreciating that the etiology of teeth staining may be better understood by taking into consideration the individual cultural and social history is emphasize.
KEY WORDS: Khat , Staining effect, chemical features, treatment, etiology.
Tooth staining may occur from either extrinsic or intrinsic sources. Intrinsic sources include tetracycline staining and flourosis. Extrinsic sources include tobacco, tea and in the Saudi Peninsula and Great North Horn of Africa, Khat.
The literature is replete with information on the intrinsic and extrinsic factors of teeth discoloration. Among the well known factors are caries, trauma, medication, metallic restorations, hereditary disease, chromogenic food and bacteria.1,2,3,4, The effect of Khat chewing on teeth discoloration has received little attention, the focus of this paper therefore is to highlight the role Khat plays in this process.
Khat is one of the few leaves chewed like tobacco by some natives to induce excitation and pleasure in some parts of the world. Although some people consume this and other types of leaves for enjoyment, these plants lead to addiction and some dental problems such as gum disease, tooth discoloration and possibly oral cancer10. Its connection with plasma cell gingivitis which is a very rare lesion has also been reported.5The discoloration affects the teeth without the loss of enamel luster. This report addresses the effect of staining on natural teeth by Khat (Catha edulis Forsk) a well known plant found in East Africa, North and South Yemen.
The khat leaves and stem tips are chewed at social gathering or while alone. Khat is defined as the leaves and young shoots of Khat Edulis, evergreen shrubs of the family of Celestraceae. People in East Africa and the southern part of the Arabian Peninsula customarily chew the leaves to produce a state of euphoria and stimulation. Khat leaves contain psychoactive ingredients known as cathinone, which are structurally and chemically similar to damphetamine, and cathine, a milder form of cathinone. Fresh leaves contain both ingredients; while those left unrefrigerated beyond 48 hours would contain only cathine which explains the preference for fresh leaves. This is because cathinone, the most potent active principle of Khat, is chemically unstable. 6
A 21year old African male presented to the Howard University College of Dentistry with chief complaint of “all of my teeth are discolored and I need to do something”. His medical and dental history was reviewed. His medical history had no positive findings and his dental history indicated that he had never visited a dental office before. His Social history indicated that he came from Northeast Africa where Khat is customarily chewed for pleasure and enjoyment. The Patient said that he was chewing Khat on a daily bases for the last 6 to 7 years and never smoke any type of tobacco. Upon clinical examination the soft tissue showed no indication of noticeable abnormality... All teeth were present except the upper third molars and all teeth were fully erupted. Caries was detected on the occluso-lingual of the maxillary posterior teeth and facial of the maxillary anterior teeth. Pitted enamel was also noticed on the mandibular anterior teeth. A panorex and four bite wing x-rays were taken and the radiographs showed no hard tissue abnormality with the exception of slight to moderate generalized bone loss noticed especially in the mandibular posterior teeth. Percussion and palpation were performed to rule out possible non vital teeth. The result was negative. Periodontal probing depth was 2-3 mm with no bleeding observed. All teeth were discolored on the buccal, lingual and interproximal areas. The mandibular first molars and anterior teeth showed faucet wear due to continuous chewing of the Khat. The discoloration range was from dark-yellowish to black. A sharp dental scaler was used in an attempt to remove the stains unsuccessfully.
Khat chewing usually begins around age twelve and above, with no gender or social class limit. Unlike tobacco chewers, khat chewers never spit out the juice which is extracted during chewing process. Instead they swallow the juice, and the leaves are left in the oral cavity. Khat has a slightly bitter taste, so most khat chewers mix small amounts of sugar with it in order to avoid the bitterness of the khat. Coffee, tea or soda (cola) should be present during the course of chewing. Many chewers smoke cigarette while they are chewing.
Stain associated with teeth is caused by the presence of chromophores (colored agents). Chromospheres arise from two chemical sources: organic compounds (ie. Carotene), inorganic transition metal ions (ie. iron and tin), and combinations (ie. blood that has both iron and the colored prophyrin ligand). These stains can be extrinsic stains on the surface of the teeth and or intrinsic stain within the teeth. The tendency for Khat to cause staining of teeth among the chronic users is not in doubt as reported by Naggeb Hassan et al.7Extrinsic stains can be removed through abrasion and/or bleaching. However, intrinsic stains (in the tooth) are bonded within the structure of the tooth, and hence cannot be reduced by brushing or any abrasive process, but can only be reduced with penetrating bleaching agents.
Intrinsic staining can be the result of several processes. Before tooth eruption during tooth development, ingestion of excess fluoride or use of tetracycline can produce staining. Developmental disorders such as amelogenesis imperfecta and dentinogenesis imperfecta and hematologic disease such as erythroblastosis fetalis and Sickle-Cell Anemia can also lead to intrinsic tooth stain.7 consequently; a dentist must be knowledgeable enough to make a decision on the available modalities of treatment. However, in this case more aggressive cosmetic therapy such as veneers or crowns appear to be necessary. Treatment of discolored tooth/teeth should be done preferably with non-invasive method (whitening) before reverting to a non-reversible method. Stained teeth should be evaluated carefully and the etiology determined before any definitive treatment plan is developed. When used appropriately, tooth-whitening methods are safe and effective.8
The addictive property which this plant possesses is a major concern. Other problems from the continuous usage which are dental related include gum disease, and possible oral cancer, as shown in a recent retrospective studies.9 In a survey that reviewed cancers for the past two years there were 28 head and neck cancer patients, 10 of whom presented with a history of having chewed Khat. One of these was a case of metastatic cervical lymph node and unknown primary, one was a parotid tumor and the remaining eight presented with oral cancer and All were non-smoking Khat chewers and all of them used Khat over a period of 25 years and longer.10
It is believed that Khat may contain some amount of fluoride (F) in its leaves. Khat samples from Yemen were analyzed by assay and found to posses negligible amounts of F in the leaf(<0.02 microg F/ml in saliva and 0.06 microg F/ml in saliva after chewing, 0.93 microg total F/g in dried leaf, 2.07 microg total F/g in ash.11
Discoloration of the teeth is the result of some multiple outside sources that affect the teeth to stain. The case presented above indicated that based on the evidence (long time khat chewer) that chewing khat can contribute to some kinds of external and possible internal teeth stains. The cause of internal staining may be from swallowing of the Khat juice due to the fluoride content of the Khat leaves. As dental clinicians, we must be aware of the effect of chewing Khat on oral tissues in the light of influx of immigrants from different parts of the world to the U.S increasing every year. We will in all likelihood see patients with discolored teeth in our daily routine oral examination. It is therefore wise to approach each individual patient based on individual cultural backgrounds. Teeth staining secondary to Khat is a potential finding in patients immigrating from the Arabian Peninsula and Northeastern Africa.
Fig. 1. Discolored teeth dark-yellowish to
Complete black on posterior area.
Fig. 2. Radiograph show no abnormality on a
Fig. 3 a, Packed Khat ready for the market
b, Fresh Khat ready to be chewed
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First Published November 2006