In reply to the letter to the editor regarding “Clinical outcomes of teeth adjacent to the site of mandibulotomy or mandibulectomy in patients with head and neck cancer: results from a multidisciplinary mono-institutional head and neck tumor board”

Abstract

This paper aims to reply to Somay et al., regarding their comment to a previous paper from our group, titled “Clinical outcomes of teeth adjacent to the site of mandibulotomy or mandibulectomy in patients with head and neck cancer: results from a multidisciplinary mono-institutional head and neck tumor board”.

The following concerns were addressed:

1. Within the limits of a case series, mandibulectomy might be considered a risk factor for the loss of tooth vitality as well as mandibulotomy.

2. Root canal therapy before surgery on the teeth adjacent to the surgical site could be an appropriate strategy, although in some cased it may involve teeth which are not destinate to have endodontic complications.

3. Dose-volume data of the included teeth were provided: the impact of radiotherapy (RT) as a confounding factor seems not to be as relevant as Somay et al. have pointed out.

We appreciate Somay et al. for their constructive comments on our study [1].

In our paper, we reported how the loss of dental pulp vitality is a frequent finding after mandibulotomy and mandibulectomy.

One concern was this: “paramedian mandibulotomy offers a significant advantage by reducing the risk of alveolar bone resorption and tooth loosening.”

Although paramedian mandibulotomy can offer several advantages when compared to mandibulectomy [2], the evidence that this procedure is safer than mandibulectomy with regard to the marginal teeth is limited to a radiological study [3], which cannot be considered as reliable as a clinical evaluation. Thus, in light of the available limited evidence, mandibulectomy might be considered a risk factor for the loss of tooth vitality as well as mandibulotomy, considering that the trauma itself, during surgical intervention and mandibulotomy, might determine a negative response to sensitivity tests and necrosis of the teeth.

Another concern was “Additionally, proposing preoperative root canal treatment for the teeth in the vicinity of the surgical site as a viable strategy to reduce postoperative complications may not be warranted for every patient undergoing mandibular surgery, especially if adjuvant radiotherapy (RT) is not indicated. Therefore it may be more appropriate to decide the actual need for root-canal treatment after the final pathological examination results become available, which will determine whether adjuvant RT is indicated.”

We want to deeply thank the authors for their proposal. Advantages and disadvantages of root canal treatment before major oncologic surgery have been thoroughly discussed within the paper. Briefly, preventive root canal therapy can become, under certain circumstances, an overtreatment, considering that some teeth preserve a positive response to sensitivity testing.

In particular, while preventive root canal treatment should be offered to all the teeth with caries, planning the endodontic treatment of a healthy tooth may be debatable. However, it should be noted that the endodontic treatment of a vital tooth is highly predictable [4], and that the endodontic treatment of a healthy tooth could be considered of minor importance than the prevention of an osteoradionecrosis (ORN), for which an apical periodontitis is a recognized risk factor [5]. On the other hand, the performance of an endodontic treatment after surgery may be significantly limited by the reduced mouth opening and by the presence of apical periodontitis [6, 7]. Within this clinical scenario, although root canal therapy seems to be a safe procedure also after RT [8], our report shows that, in some cases (3/23, 13%), the lack of vitality of the included teeth, as well as their periodontal impairment, led to an unavoidable extraction. Considering that teeth extractions appear to be associated with a higher risk of ORN when conducted after [9] than before RT [10], we believe it is more appropriate to develop a treatment plan, whether endodontic or extractive, before the start of RT.

However, within our sample, the loss of vitality was a frequent finding also in non-irradiated patients (4/7, 57.14%), involving, in all cases, previously healthy teeth. Thus, preventive endodontic treatment might be justified independently on the future need for adjuvant RT. Nevertheless, the evidence beyond this suggestion is limited, and further prospective studies are needed to directly compare the efficacy of preventive treatment versus a more cautious “wait and see approach” on the prognosis of teeth directly neighboring the ostectomy site.

Another comment to be addressed was the following: “The current study did not include detailed dose-volume information regarding the RT dosage received by the specific jaw volumes and the volume of the teeth at the margins of the osteotomy.”

We really appreciated this comment, considering the efforts that our research group is producing in analyzing the impact that RT may have on oral health [11]. In order to better assess this issue, we retrospectively evaluated the RT dose received by the included teeth, as described in a previous investigation [12].

The majority of the included patients received a curative dose on the oral cavity: 60.48 Gy (range: 30.6–73).

The following RT dose was found among the single teeth:

Mean alveolar RT dose for non-vital teeth: 45.45 Gy (range: 11.25–66.2).

Mean alveolar RT dose for vital teeth: 43.1 Gy (range: 27.9–60.6).

Although these results are suggestive of the homogeneity of the sample, a statistical analysis to highlight the risk factors for the loss of vitality was not considered appropriate, as clearly stated within the paper, but the impact of RT as a confounding factor seems not to be as relevant as Somay et al. have pointed out.

Nevertheless, we completely agree with Somay et al. that large-scale trials are needed to give more strength to the initial evidence provided by our investigation, and that definite clinical guidelines cannot be derived from this initial investigation.

Author contributions

C.R., R.C. and C.L. wrote the main manuscript text. G.G., G.A., J.G., L.T., A.C. and P.G. reviewed the manuscript.

Funding

N/A.

Data availability

The data that support the findings of this study are available from the corresponding author, C.R., upon reasonable request.

Declarations

Ethics approval and consent to participate

N/A.

Consent for publication

N/A.

Competing interests

The authors declare no competing interests.