Introduction

The treatment of periodontal disease is divided in four steps: initial diagnosis and patient motivation, cause-related nonsurgical therapy, optional surgical intervention, followed by supportive periodontal care. Central aspect of all these stages is the aim to remove (or control) pathogenic biofilm to establish a favorable environment (Lisa J. A. Heitz-Mayfield 2005). There are a variety of adjunctive measures (such as antibiotics and other antiseptic modalities) that may be considered during each step. The relevance of these is discussed in other chapters in this book. This chapter therefore focuses on the relative effectiveness and related issues of surgical versus nonsurgical periodontal therapy.

The understanding of the etiopathogenesis of periodontitis and associated diseases has developed significantly in recent years. These changes are most prominently reflected in the 2018 Classification of Periodontal Diseases (Caton et al. 2018). Notwithstanding the development of novel therapeutics, mechanical debridement remains at the core of the treatment of periodontitis (Sanz et al. 2020). However, the relative effectiveness of surgical vs. nonsurgical approaches is continuously discussed and the subject of ongoing research.

Evidence-based Outcomes

Antczak-Bouckoms et al. was one of the first publications relating to investigation of relative effectiveness of surgical versus nonsurgical methods of treatment of periodontal disease (Antczak-Bouckoms et al. 1993). This meta-analysis included the results of five randomized controlled trials deemed suitable by the authors. All studies compared similar treatments: modified Widman flap versus scaling and root planing under local anesthesia.

Interestingly, the authors highlighted the importance of choice of outcome measures. When considering reduction of probing depths as the goal of therapy, the surgical treatment groups exhibited superior outcomes. Attachment levels, on the other hand, improved more in the nonsurgical treatment group. Overall, all these differences between groups became smaller over follow-up time and were nonsignificant after 5 years. Only the deepest initial pocket probing depths (>6 mm) showed improvement after 5 years in the surgical versus the nonsurgical group. However, this difference was limited to around 0.5 mm.

The findings of two further systematic reviews published in 2002 (L. J. A. Heitz-Mayfield 2002; Hung and Douglass 2002) are consistent with the previously mentioned work. A further review paper attempts to reconcile the minor differences between the results of the three published systematic reviews (Lisa J. A. Heitz-Mayfield 2005).

The most recent systematic review on the topic was conducted by Sanz-Sanchez et al. in preparation for the EFP S3-level guideline (Sanz et al. 2020; Sanz-Sanchez et al. 2020). This review included 36 randomized controlled trials investigating the effectiveness of subgingival instrumentation versus access flaps in reduction of probing depths. Consistent with previous reviews, the results confirmed that the surgical approach is superior in terms of probing depth reduction in deep pockets both in the short and long term. Probing depths of initially moderately deep pockets (4–6 mm) benefit from greater probing depth reduction with a surgical approach in the short term, but this difference becomes negligible in the long-term follow ups (see Figure 9.1).

All of these systematic reviews and their results have to be interpreted with caution. The high variability of included studies—such as sample sizes, patient selection, follow-up times, treatment modalities, chosen outcome measures—pose a limitation on comparability and generalizability. There also have been suggestions that nonsurgical approaches are more promising on single rooted teeth with initially moderately deep or deep pockets (Sanz-Sanchez et al. 2020).

Nonetheless, it can be concluded that in deep pockets, i.e., initial probing depths of 7 mm or more, surgical approaches are superior in terms of probing pocket depths reduction compared to nonsurgical approaches.

Author’s Views/Comments

As stated above, the goal of periodontal therapy may be defined as “to arrest the inflammatory disease process by removal of the subgingival biofilm and establish a local environment and microflora compatible with periodontal health” (Heitz-Mayfield 2005). While this is a sensible definition in light of our current understanding of the pathogenesis of periodontitis, it does not lend itself to the assessment of success or failure of any periodontal intervention.

In terms of objective clinical periodontal outcomes, we may define the goals of periodontal therapy to be—at least in the short-term—the reduction or elimination of periodontal pockets and the prevention of further attachment loss. Periodontal pocket depth and attachment loss have several characteristics that, for clinicians, make them almost intuitive endpoints to measure success or failure of periodontal therapy. Firstly, periodontal pocket depth and attachment loss are literally defining signs of periodontitis, given that periodontitis is defined as a chronic inflammatory