Our article (Pazera P, Fudalej P, Katsaros C. Severe complication of a bonded mandibular lingual retainer. Am J Orthod Dentofacial Orthop 2012;142:406-9), published in the September issue, demonstrated a severe unwanted effect of a lingual flexible spiral wire retainer. The goal of our article was to attract the attention of the orthodontic audience to possible adverse effects of these retainers that can seriously affect the oral health in some orthodontic patients.

We were pleased to receive the letter of Dr Zachrisson, who introduced the flexible spiral wire retainer 35 years ago. In his letter, he discussed issues related to dehiscence formation and bone regeneration in orthodontic patients. We consider his communication helpful to readers, because it broadens the discussion that is always limited by the nature of a case report. We are fully aware of the literature Dr Zachrisson mentioned. Recently, our team published a systematic review in which the most relevant studies cited by Dr Zachrisson were thoroughly discussed.

The meaning of our statement, “to our knowledge, this has never been documented before,” in the Discussion section that attracted Dr Zachrissons’s attention was that our report is likely to be the first documentation of partial buccal bone regeneration in an orthodontic patient by using a contemporary visualization method (cone-beam computed tomography). We believe that this does not conflict with the literature Dr Zachrisson mentioned for the following reasons: 5 of the 6 studies on buccal bone regeneration that he listed were animal experimental investigations. Although they provide valuable information, it is not certain that dehiscence formation and bone regeneration occur in humans and animals in the same way. It has been shown that humans can react differently from animals to the same stimulus. Moreover, the human study that Dr Zachrisson mentioned is not related to our findings, since it described the remodeling of the palatal cortex in response to palatal movement of the maxillary incisors. In addition, the anatomic region in this study is not considered to be prone to periodontal defects and thus is not comparable with the mandibular anterior region.

Although partial buccal bone regeneration was observed in our patient, this finding cannot necessarily be extrapolated for other patients, especially in the mandibular incisor region when severe unwanted root movement is accompanied by development of extended gingival recession. Therefore, it is important that orthodontists, dentists, and patients are aware of possible complications of bonded flexible spiral wire retainers, so that problems can be detected at an early stage, before severe unwanted tooth movements occur.