Together with the identification of the agents causing the recession, the characterisation of the anatomical structures surrounding an exposed root surface demands special attention as well. This is because the diagnosis of the defects, as similar to all other fields of medicine and dentistry, can provide a “snapshot” and guide the treatment plan options.

Of an assorted group of classification systems described in the literature created to characterise and “quantify” the amount of tissue loss over the exposed root surface [28–33], the “classification of marginal tissue recession” proposed by Miller in 1985 [30] is certainly the most used and accepted one by regular clinicians and the scientific community. This classification system is based on the amount of soft tissue lost over the root surface and the condition of interproximal periodontal tissues, and it can separate defects into four classic morphological groups (Fig. 3.2):

The detrimental impact of smoking on nonsurgical and surgical periodontal therapy has long been studied [3, 7, 9, 10]. There is clear evidence that smokers may benefit from soft tissue root coverage; however, the use of SCTG does not provide the same effect of treatment as that achieved in nonsmokers [3, 7, 9, 10]. At 6 months post-therapy, smoking may affect the outcomes of therapy. It may be expected that there are 17.5 % less root coverage and around 36 % fewer sites with complete root coverage in smokers treated with SCTG [10]. By taking these numbers into account, it can be seen that at least three defects in smokers need to be treated to result in one more defect reaching CRC than in the nonsmokers [10]. At 1 year after treatment, recessions treated with SCTG + CAF present significant less root coverage for smokers (89.0 %) than nonsmokers (92.6 %). At 3 years, these values drop to 68.0 % versus 81.5 %, respectively [10]. Likewise, the number of sites exhibiting complete root coverage decreased between these time periods in both groups (i.e. for nonsmokers, it moved from 72.5 to 42.5 %), but within smokers, it was very drastic (62.1–12.5 %) [10].

These results may be associated to interleukin 1 gene polymorphism (i.e. smokers testing positive to it seem to be at an increased risk of periodontal breakdown after treating the recessions) [34], the anatomy of the palatal vault of smokers (less vascularised/inferior number of blood vessels) [35] and the flap thickness (it has been suggested that defects ≥0.95 mm were 100 % covered in nonsmokers, while for some smokers, it did not happen) [36]. These conditions seem to influence revascularisation and incorporation of the SCTG and overall wound healing [3, 10]. On the other hand, the effect of treatment to smoking and nonsmoking patients with CAF seems the same at 6-month follow-up; however, there is limited information available for a definitive analysis [3, 10]. In addition, heavy smokers (≥10 cigarettes/day) may be benefited by the treatment of their recessions as well, but the use of graft or flap procedures alone may not be enough [3, 10]. The use of enamel matrix derivative associated to ADMG + CAF suggests better clinical outcomes than defects treated without such a protein [37].

For recessions presenting also non-carious cervical lesions (i.e. root abrasion due to traumatic toothbrushing), the use of resin-modified glass ionomer or microfilled resin composite prior to surgery (and the subsequent coverage of part of these restorations) does not cause detrimental negative effects on bleeding on probing [38–43] or subgingival microflora [44]. The depth and the vertical extension of the cervical lesion should be assessed prior to any treatment. Deeper cervical lesions may lead to greater coverage, but CRC of the defect might not be achieved [45].

Moreover, the option of restoring or not these defects before treatment may be critically accounted (Fig. 3.3), since there has not been a significant difference in the amount of root coverage between restored and non-restored lesions, and virtually half of the cervical restorations presented colour change after 2 years of treatment (e.g. an aditional question may arise, how these restoration can be removed/changed?). Also, SCTG + CAF seems to perform better than CAF [42]. Thus, it seems more advantageous to treat the recession first (i.e. to perform the chosen root coverage procedures), wait for early healing (at least 6 months) and then perform the definitive restoration of the remaining cervical lesion. Zucchelli et al. [46] suggested that the selection of procedures should be based on the following types of combined defect: (a) Types I and II (radicular cervical lesions plus Class I or II GR), RC alone; (b) Type III (crown-radicular cervical lesion plus Class I, II or III GR), coronal and radicular odontoplasty + restoration + RC; (c) Type IV (radicular cervical lesion plus Class III or crown-radicular cervical lesion plus Class I or II with the deepest point of the cervical lesion localised at the level of the anatomic crown), coronal and radicular odontoplasty + restoration + RC; and (d) Type V (radicular cervical lesion plus Class III or IV GR with the cervical lesion located “on that portion of the root surface that was not coverable with soft tissues”), restoration alone [46]. Additionally, the contralateral tooth may be used to identify and reconstruct the cemento-enamel junction level of the teeth with non-carious cervical lesions [47].

With respect to teeth with caries or previously restored, these may be successfully treated, but the carious dentin/root restorations need to be removed and the root surfaces be meticulously planned prior to surgery (Fig. 3.4). Independently of treating exposed roots with or without caries/lesions, it is of paramount importance to perform thoroughly “cleaning” of the anticipated surface to be covered. Scaling and root planning with hand or ultrasound instruments and root polishing may be used [10]. Chemical agents like 1 % citric acid, EDTA and tetracycline hydrochlorides may be used as well, but these will not promote additional benefits to the surgical therapy applied (Fig. 3.5) [2–10].

In addition, both maxillary/mandibular and anterior/posterior teeth may be equally benefited by treatment of their associated recessions, but gains in the amount of keratinised tissue can be superior in sites located in the upper arch (without importance from a clinical point of view) [48, 49]. Furthermore, evidence indicates that palatal/lingual defects may be safely treated by SCTG.

Many times, the treatment plan of recession-type defects may not only account for the best treatment option available but to the inherent characteristics of the defect/area to be treated as well. For instance, not only localised and narrow Class I recessions will be forwarded to treatment (in fact, many patients presenting such defects do not mind in treating them). The occurrence of dissimilar “clinical scenarios” may increase the degree of difficulty during decision-making once their treatment will not only lead with the best evidence available but with clinician’s experience and patients’ expectations as well. Thus, questions related to the potential treatment options available and the importance of treating that specific types of defect require attention.

With respect to the diversity of potential clinical scenarios faced day by day by clinicians attending at private clinical practice, the American Academy of Periodontology [10] in its recent workshop has pointed out some common conditions and questions that may be accounted to help them during the preparation of a treatment plan:

Is there sufficient donor tissue to be removed from the palatal vault? Is it safe to use a flap procedure alone? or Should other biomaterial be used? What factors will lead me to the best choice? [10]

How can I improve my odds of achieving a satisfactory result? Is it possible to use a flap procedure alone or should I associate a graft/biomaterial to it? Will a restorative/prosthetic approach be required? [10]

What is the best technique/material to graft over these previously restored root surfaces? Should the restoration be removed or changed? Is it safe and predictable to surgically treat these areas? [10]

Should that alter the treatment approach? Do these areas need to be restored? If yes, before, during or after the surgical procedure? [10]

Is it possible to cover carious root surfaces? After removing the caries it is obvious a restoration will be necessary. How does that change the treatment plan? Similarly to abraded surfaces, do these areas need to be restored before, during or after the surgical procedure? [10]

What are the risks and benefits associated to the use of allogenous or xenogenous graft substitutes? Do they provide an evidence of long term stability? [10]

What technique should be used to achieve these goals? [10]

Are the results of therapy stable? What is known about the attachment of the graft/flap to the root and should I care? Is it possible to estimate the outcomes and propose treatment options (i.e. establish a decision tree)? Is it possible to obtain satisfactory results when treating smoking patients? [10]

Are the geometry and the degree of recession important (e.g. narrow and deep versus wide and shallow)? Is the amount of available keratinized attached gingiva important in the decision making process? Does the degree of keratinized gingiva in the final outcome affect the long-term stability of cases? [10]

Information on human histology is not easy to be accessed due to inherent ethical conditions related to it. Within the available cases published in the literature, on acellular dermal matrix graft, coronally advanced flap, enamel matrix derivative, free gingival graft, guided tissue regeneration, laterally positioned flap, subepithelial connective tissue grafts and xenogenic collagen matrix, wound healing may be anticipated consisting of long junctional epithelium and connective tissue attachment (with fibres parallel to the root surface) (Fig. 3.6) [10]. Additionally, some degree of tissue regeneration may happen in the most apical portion of the defects mostly for EMD- and GTR-based procedures (i.e. new connective tissue attachment with newly formed cementum and crestal bone) [10].

Consequently, after treatment, it is expected a shallow gingival sulcus that may be maintained over the long term when the causal agent was treated/removed. On the other hand, when the causal agent of the recession is not removed, apical migration of the gingival margin may quickly occur. In clinical terms, it should be noted that the majority of patients seeking root coverage procedures are not periodontitis patients and their defects are of traumatic origin (e.g. traumatic toothbrushing). For such patients, clinicians should pay attention to correct/adequate detrimental hygiene measures (Fig. 3.7) and remove other potential traumatic agents (e.g. oral piercings) in order to maintain the stability of the result achieved with the treatment [10].

In general clinical terms, which results should I expect at private practice in terms of unusual healing response and long–term stability?

Unusual healing responses associated to the use of SCTG, such as root resorption [50], formations of cyst-like areas [51, 52] or bone exostosis [53], were described in the literature but involve a very restricted number of defects. In general terms, these unexpected outcomes do not weaken the safety and success of the connective graft. Additionally, some degree of creeping attachment (i.e. the coronal displacement of the gingival margin covering exposed root surfaces) may occur when subepithelial connective tissue grafts, and mainly free gingival grafts, are the choice of treatment [54]. For all of these unusual conditions, their occurrence cannot be anticipated.

The recent AAP paper [10] observed that at least 70 % of recession reduction can be anticipated 2 or more years after treating the recessions, but the number of defects showing 100 % defect coverage can drastically vary (up to 67.5 % of variation) depending on the type of surgical procedure and the follow-up period. For instance, Pini Prato and co-workers [55] described that “a coronal displacement of the gingival margin was observed in the SCTG + CAF treated sites, while an apical relapse of the gingival margin was found in the CAF-treated sites between the 6-month and 5-year follow-ups”.

It seems that the improvement on the keratinised tissue band, in terms of width and thickness gain (i.e. the concomitant root coverage and biotype change), is also responsible for keeping the stability of the results obtained with therapy. Overall, the use of subepithelial connective tissue grafts or enamel matrix derivatives in association to the coronal advancement of the gingival margin over the exposed root surface can provide the most stable outcomes. In contrast, coronally advanced flap alone and guided tissue regeneration were described as those procedures losing significantly more soft tissue [2, 4, 5, 8–10].

In addition, the elimination of the causative agent of the recession (e.g. traumatic toothbrushing, periodontal disease, etc.) and compliance with regular periodontal maintenance seem directly associated to long-term stability of results achieved with surgical therapy [56].

Flap preparation and suture may not be underestimated during the surgical sequence. Recently, Burkhardt and Lang [57] highlighted some important issues on these surgical steps that demand special attention, and these are reproduced below:

Information on the inclusive evaluation performed by the American Academy of Periodontology at its recent workshop on Enhancing Periodontal Health Through Regenerative Approaches were used to answer specific important questions commonly made by clinicians in their daily practice, regarding the best possible choice of treatment modality to satisfy their patients’ needs [10].

Regarding the specific questions on soft tissue root coverage addressed by the AAP, the following can be considered during the decision-making process (as reported in the publication by Chambrone and Tatakis [10]):

The treatment of a gingival recession is safe and leads to significant clinical reductions in recession depth and attachment level within Miller Class I and II defects. Class III recession may be benefited as well, but the amount of coverage will be based on the amount of interproximal tissue lost (usually the amount of root coverage expected is based on the position of the gingival margin of the adjacent teeth).

Altogether with the improvements on the aesthetic condition, a decrease of dentin hypersensitivity and prevention of caries/cervical lesion over the exposed root surface may be expected. Both single and multiple recessions may be benefited by periodontal plastic surgery, but apart from the type of procedure or recession, the rationale for treatment should be focused on the clinician’s knowledge and patient-centred outcomes (e.g. aesthetic assessment, functional limitations, discomfort, root sensitivity and preferences). Overall, a small percentage of patients may experience early post-operative bleeding, swelling and pain, but these do not modify the final aesthetic/functional outcomes. Moreover, it should be noted that the amount of vascularisation adjacent to a root surface is crucial when a flap is moved over avascular sites (root surface); consequently, it is adequate to extend the base of the pedicle (flap) to improve the local blood supply during early healing [56].

Likewise, flap stabilisation and suture coronal to the CEJ are important and desirable too [56], but other local conditions should be considered during the decision-making process (choice of best procedures), such as periodontal conditions (lack of biofilm inflammation), recession anatomy (classification, depth and width), anatomy of adjacent soft tissue (thickness and presence of keratinised tissue) and tooth/root conditions (tooth position and root prominence) [56].