INTRODUCTION:

In this scientific world the use of antibiotics for diseases is a new trend. One such antibiotic involves Tetracycline and its derivatives. Tetracyclines are a family of compounds, basically polycyclic napthacene carboxamides.[1]. The gross structure of oxytetracycline was first determined by Woodward and collaborators using chemical degradation of the compound and ultraviolet and infrared spectral and analytical techniques. X-ray crystallographic structural analyses on aureomycin hydrochloride (chlortetracycline) unambiguously demonstrated the concordance with terramycin hydrochloride (oxytetracycline) at the level of the configuration of asymmetric carbon atoms. Similarity in chemical and biological properties presumes this concordance.[2][3]. They were introduced in 1948 as broad-spectrum antibiotics that are used in the treatment of some common infectious diseases in children and adult such as severe acne, urinary, periodontal disease and intestinal disorders. Discoloration of adult teeth occurs when long-term treatment for acne is undertaken.[7].

In early 1960’ tetracycline based medication are suggested in clinical sites without the knowledge that it would cause discoloration of teeth both in primary and permanent dentitions. Biochemical function of tetracycline is that it is an inhibitor, which inhibits the cell growth during translation, inhibits protein synthesis by dislodging ribosome.[8]

Effect on developing foetus:

It is usually recommended that pregnant women are not advised to take tetracycline antibiotic during the second and third trimester stage. This is because tetracycline derivatives can cross through the placental barrier and affects the growing foetus and should be avoided from 29 weeks in utero until full term to prevent incorporation into the dental tissues. Since the permanent teeth continue to develop in the infant and young child until 12 years of age, tetracycline administration should be avoided in children below this age and in breast-feeding and expectant mothers.[6]. Further there is a marked discoloration of the primary dentition. The colour changes involved depend upon the medication used, the dosage and the period of time over which the medication was given. Teeth affected by tetracycline have a yellowish or brown-grey appearance which is worse on eruption and diminish with time. Exposure to UV-radiation changes the colour to brown, the anterior teeth are particularly susceptible to light induced colour changes. The various derivatives of tetracycline gives off different colour changes, for e.g., chlortetracycline produces a slate grey colour and oxytetracycline causes a creamy discolouration.[4][5]. Depending on the specific tetracycline used, the type and severity of discoloration may vary.

How Tetracycline works on discoloration of Primary dentition?

Tetracycline travels in the blood to the coronal portion of the pulp, where there is an extensive vascular network. It is carried through the branching capillaries of the subodontoblastic area to the terminal loops, which extend upward between the odontoblasts to end in the predentin. The tetracycline molecule transported to this area is believed to bond chemically to calcium ions. This diffuses into the tissues to the site of mineralization of the dentin, which is the junction of predentin and dentin.' Thus a stable tetracycline calcium orthophosphate complex is formed. This fluorescence gradually disappears and the tooth discoloration reportedly changes from yellow to brownish colours in children: this change is likely due to an oxidation product of tetracycline, which is light induced.[9-11].

Side effects on teeth due to tetracycline medications:

Tetracycline and oxytetracycline cause a yellow discoloration, whereas chlortetracycline produces a grey-brown discoloration. Evidence suggests that, of all the Tetracyclines, oxytetracycline causes the least tooth discoloration. Tetracyclines (e.g.Ledermix—triamcinolone acetonide and demethylchlortetracycline) used within the tooth for endodontic therapy may alsocause dark grey-brown discoloration. However, other anti-microbials, such as minocycline and ciprofloxacin, have also been reported to cause tooth discoloration.[12-14]. List of some tetracycline medications and its derivatives are:

· Tetracycline

· Chlortetracycline

· Oxytetracycline

· Demeclocycline

· Doxycycline

· Lymecycline

· Meclocycline

· Methacycline

· Minocycline

· Rolitetracycline

· Minocycline [15].

Minocycline:

The side effects of Minocycline on the oral cavity is the singular occurrence of "black bones", "black or green roots" and blue-gray to gray hue darkening of the crowns of permanent teeth. The prevalence of tetracycline and minocycline staining is 3-6%. The mechanism of minocycline staining is still unstudied.[7]. Unlike tetracycline, minocycline has been reported to cause generalized intrinsic tooth staining post-eruption. This staining is distinctly different from that caused by Tetracycline. Staining of the adult dentition appears to occur in 3-6% of patients taking long-term minocycline at > 100 mg daily. The onset of discoloration can occur at any time from 1 month to many years after the initiation of treatment. The exact mechanism by which minocycline causes tooth discoloration is controversial and still under investigation.[20-22].

Table 1. Comparison between Tetracycline- and Minocycline-stained Teeth

	Tetracycline	Minocycline
Colour of staining	Yellow to brow/grey	Green/grey,blue/grey
Pattern	Gingival margin or cervical third or band relating to the crown	Incisal edge and, most intensely, the middle third of the crown.
Fluorescence	Yellow fluorescence	None clinically but will fluoresce in an acid medium
Severity	Severe	Less severe
Resolution with drug stoppage	None	Resolutions are rare in teeth.

Treatment for tetracycline staining of teeth:

Treatment of tetracycline discoloration is challenging. These teeth cannot be successfully bleached externally, because the greyish stain is concentrated in the inaccessible primary inner layer of the secondary dentin. External bleaching may temporarily lighten the enamel surface, but the result does not persist. However, elective root canal therapy followed by internal bleaching will successfully and permanently bleach the teeth.[23-26].

Removal of the stains involves aesthetic treatment. However the severity of the stain discourages any attempt to whiten the teeth using bleaching agents or fluorosis. If so done it does not remove the bluish grey stains completely. Treatment usually involves placement of veneers or crowns to cover the darkened teeth. [16-19]. The combination of in-office and home whitening provided a faster whitening result, proper monitoring of the progress of whitening throughout the extended period and continuous motivation for the patient to complete the whitening of the stained teeth. However crown replacement may change the morphology of the tooth. Even At-Home bleaching is inconvenient, high cost and repeated appointment and time-been. The most options left to the patient are (I) root canal therapy of six anterior teeth in conjunction with internal bleaching,(2) placement of laminate veneers, and (3) no treatment.

CONCLUSION:

Since the consumption of antibiotics like tetracycline becomes rapid in these decades and its disadvantages come before the screens. Prolonged usage of tetracycline medications gives off teeth discoloration. The colours vary according to it type of its derivatives. It is necessary to know some knowledge about tooth staining for dental surgeons in order to enable a correct diagnosis to be made when examining a discoloured dentition patient. Pregnancy and lactating women should avoid the usage of tetracycline medication especially during second and third trimester period. We can avoid the future medication by taking the present precaution. So at this time the best treatment is prevention. As though Teratogenesis can be prevented and congenital diseases percentage can be minimised. Try not to get your teeth destroyed from its amazing symmetry, and then you can’t smile.

REFERENCE:

1. Boyne, P. J., The use of tetracycline in studies of bone healing. Advan. Oral Biol. 3; 121, 1968.

2. Hochstein, F. A., Stephens, C. R., Conover, L. H., Regna, P. P., Pasternack, R., Brunings, K. J., and Woodward, R., Terramycin VII. The structure of terramycin. J. Amer. Chem. Soc. 74; 3708, 1952.

3. Donahue, J., Dunitz, J. D., Trueblood, K. N., and Webster, M. S., The crystal structure of aureomycin (chlortetracycline) hydrochloride. Configuration, bond distances and conformation. J. Amer. Chem. Soc. 85; 851, 1963.

4. Moffitt J M, Cooley R O, Olsen N H, Hefferen J J. Prediction of tetracycline induced tooth discolouration. J Am Dent Assoc 1974; 88: 547-552.

5. Van der Bijl P, Pitigoi-Aron G. Tetracyclines and calcified tissues. Ann Dent 1995; 54: 69-72.

6. British National Formulary, March 1999; 37: 254-256, BMJ Books: London, UK.

7. Effect of Tetracycline and other tetracycline derivatives in discoloration of teeth http://www.ncbi.nlm.nih.gov/pubmed/ 15485524#

8. Book: “Biochemistry” Authors: U. Satyanaarayana, U. Chakrapani. Section 5. 5^th ed.

9. Ten Cale AR: Oral Histotogy. ed 3. St Lotiis, CV Mosby Co, lyS'». pp 1WI-1S3.

10. SkinnL'r CW. Niilbandian J: Tctrac-ydincs and mineralized tissues; review and perspectives, Yali'J Biot Med 1975;48:377-397.

11. Wallman IS, Hilton HB: Teeth pigmented by tetraeycline. Lancet 1952:1 :S27-S29.

12. Driscoll MA, Rothe MJ, Abrahamian L, Grant-Kels JM (1993). Long-term antibiotics for acne: is laboratory monitoring necessary? J Am Acad Dermatol 28:595-602.

13. Wallman IS, Hilton HB (1962). Teeth pigmentation by tetracycline. Lancet I:827-829.

14. Kim ST, Abbott PV, McGinley P (2000). The effects of Ledermix paste on discolouration of immature teeth. Int Endod J 33:233-237.

15. Wikipedia, http://en.wikipedia.org/wiki/Tetracycline_antibiotics

16. Haywood VB, Leonard RH, Dickinson GL. Efficacy of six months of nightguard vital bleaching of tetracycline-stained teeth. J Esthet Dent. 1997;9:13-19.

17. Leonard RH Jr, Haywood VB, Eagle JC, et al. Nightguard vital bleaching of tetracycline-stained teeth: 54 months post treatment. J Esthet Dent. 1999;11:265-277.

18. Matis BA, Wang Y, Eckert GJ, et al. Extended bleaching of tetracycline-stained teeth: a 5-year study. Oper Dent. 2006;31:643-651.

19. Leonard RH Jr, Haywood VB, Caplan DJ, et al. Nightguard vital bleaching of tetracycline-stained teeth: 90 months post treatment. J Esthet Restor Dent. 2003;15:142-153.

20. Dodd MA, Dole EJ, Troutman WG, Bennahum DA (1998). Minocycline associated tooth staining. Ann Pharmacother 32:887-889.

21. Berger RS, Mandel EB, Hayes TJ, Grimwood RR (1989). Minocycline staining of the oral cavity. J Am Acad Dermatol 21:1300-1301.

22. Poliak SC, DiGiovanna JJ, Gross EG (1985). Minocycline-associated tooth discolouration in young adults. J Am Med Assoc 254:2930-2932.

23. Walton RE, O'Deli NL, Myers DL, et al: External bleaching of tetracycline stained teeth in dogs, y foí/oí/1982:8:536-542.

24. Aboü-Rass M: The elimination of tetracycline discoloration by intentional endodonties and internal bleaching. J Endod iy82;S:IOl.

25. Walton RE, O'Dcll NL, Lake ET, et al: Internal bleaching of tetracycline stained teeth in dogs. J Endod 1983:9:416-420.

26. Lake FT, O^Dell NL, Walton RE: The effect of internal bleaching in dentin. 7 £jii/od 1985;11:I41.

Received on 11.12.2013 Modified on 05.02.2014

Research J. Pharm. and Tech. 7(6): June, 2014; Page 712-714