Letter to the Editor

Dear Sir,I wish to comment on the article ‘Pulp revascular-ization of replanted immature dog teeth aftertreatment with minocycline and doxycycline as-sessed by laser Dopler flowmetry, radiography, andhistology’ by Ritter et al., that appeared in yourjournal (2004, 20:75–84).

Reading the article thoroughly, I was surprised tosee that the authors did not refer to the article‘Effect of minocycline on healing of replanted dogteeth after extended dry time’ by Bryson et al.(Dental Traumatology 2003, 19:90–95). The conclusionof that article was that there is no significant effect ofthe drug, and the use of minocycline is notrecommended. In another paper that was publishedin Dental Traumatology 2003, ‘The effect of topicalminocycline on replacement resorption of replantedmonkey’s teeth’, by KM Ma, V Sae-Lim (DentalTraumatology 2003, 19:96–102), the conclusion alsowas that minocycline was not effective in controllingreplacement resorption.

A search of the medical literature revealed anumber of investigations showing that minocyclineis actually an inhibiting factor in angiogenesis. Hereare a few examples:1 The tetracycline analogs minocycline and doxy-

cycline inhibit angiogenesis in vitro by a non-metalloproteinase-dependant mechanism. EAPowers et al., Cancer Chemotherapy and Phar-macology, 1995, 36(5):418–424.

2 Angiogenesis inhibition by minocycline. RJ Tam-argo, RA Bok, H Brem, Cancer Research, 1991,15:51(2):672–675.I suggest that these facts should encourage further

research into this interesting question.

Sincerely,

Ruth MillerResident in Pediatric Dentistry,Tel-Aviv University, Tel-Aviv, Israel

Response

Thank you for your interest in our paper.We feel that the papers cited in the above letter

are similar to our study only in that a common drug(minocycline) was used.

The aim of our paper was to enhance revascu-larization by the use of a long acting antibacterialagent minocycline. We did not claim nor do we feelthat the drug did anything else other than keep theroot surface and therefore the necrotic space free ofbacterial contamination. Because of the fact that thenecrotic pulp stayed free of bacteria it could act as ascaffold for the tissue that revascularized the pulpspace.

The papers of Bryson et al., KM Ma and V SaeLim were designed to test the anti-resorptiveproperties of this same medicament as minocyclinehas reported anti-resorptive as well as anti-bacterialproperties. These studies were designed to promoteosseous replacement by keeping the teeth dry for60 min before replantation. The results indicatedthat the reported anti-resorptive properties of

minocycline did not decrease the level of osseousreplacement. As these studies had different aims anddifferent properties of minocycline were tested wedid not feel the need to reference them in ourrevascularization study.

I thank Dr Miller for her references aboutminocycline and angiogenesis. As the use of mino-cycline was successful in ‘promoting’ revasculariza-tion in our study we did not feel the need to searchout references contrary to these findings. If on thecontrary the use of minocycline did not enhancerevascularization we would have researched paperssuch as these which would have explained ournegative results.

Sincerely,

Alessandra L. S. RitterDepartment of Endodontics, School of Dentistry,University of North Carolina at Chapel Hill, ChapelHill, NC, USA

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