Prosthodontic rehabilitation of patients with stage IV periodontitis

Periodontitis is the sixth most prevalent disease in the world, affecting an estimated 1.1 billion adults globally. It is characterized by bleeding, pocketing, clinical attachment loss, radiographic signs of alveolar bone loss. The diagnosis of periodontitis has been outlined by the EFP (European Federation of Periodontology)/AAP (American Academy of Periodontology),¹ alongside clinical practice guidelines,² which have outlined evidence-based treatment strategies. These guidelines have been adapted by the British Society of Periodontology and Implant Dentistry (BSP).³

Stage IV Periodontitis describes the most severe form of the disease. The BSP implementation of the supranational EFP guidelines⁴ defines stage IV disease as cases where there is observable interproximal bone loss extending to the apical third of the root following the assessment of appropriate peri-apical/panoramic radiographs. This provides a concise and straightforward means of diagnosing patients within the framework of UK dentistry.

The EFP classification of stage IV disease differs from the BSP implementation. In the EFP classification, both stage III and IV disease present with clinical attachment loss ≥5 mm, with radiographic bone loss extending to the middle third of the root surface. Stage IV periodontitis is instead characterized by an additional need for complex rehabilitation owing to masticatory dysfunction, secondary occlusal trauma, severe ridge defects, bite collapse, flaring/drifting of teeth and having fewer than 10 opposing pairs of teeth (severe shortened dental arch).

Further clinical practice guidelines have been created by the EFP⁵ that explore the evidence base when considering the rehabilitation of patients with stage IV periodontitis. This article provides an overview of key evidence-based recommendations to implement when considering fixed or removable prosthodontic replacement options in patients with stage IV periodontitis.

Clinical assessment of a stage IV periodontitis patient

In line with the BSP S3-level treatment guidelines for the treatment of stage I–III periodontitis,³ full mouth periodontal charting, together with appropriate radiographic records, are required to assess the severity of clinical attachment loss to formulate a diagnosis. Once a diagnosis of stage IV periodontitis has been made, it is important to supplement the examination with further clinical information including:

• Subjective/objective assessment of chewing, aesthetics and phonetics;
• Tooth mobility;
• Assessment of tooth vitality (cold test/electric pulp test);
• The presence of secondary occlusal trauma;
• An assessment of the occlusion in static and dynamic relationships;
• An assessment of tooth restorability;
• Number of teeth that have been lost because of periodontitis (if records are accessible);
• Consideration of the patients concerns, preferences and finances.

This information will allow the clinician to consider an individual tooth-by-tooth prognosis and the overall case prognosis, which will inform the most appropriate treatment options for the individual (Figure 1).

Case phenotypes of stage IV periodontitis

The EFP clinical practice guidelines⁵ outlines four clinical case types with which patients with stage IV periodontitis may present:

• Case type 1: the patient with tooth hypermobility as a result of secondary occlusal trauma that can be corrected without tooth replacement. It is recognized that there is a continuum of severity and complexity of management between some stage III periodontitis patients, and case type 1 of periodontitis in stage IV.
• Case type 2: the patient with pathological tooth migration, characterized by tooth elongation, drifting and flaring, which is amenable to orthodontic correction.
• Case type 3: partially edentulous patients who can be prosthetically restored without full-arch rehabilitation.
• Case type 4: partially edentulous patients with a dentition that needs full-arch rehabilitation, either tooth- or implant-supported/retained.

This article focuses on guidance for case types 3 and 4, with an emphasis on tooth-supported replacement options.

Does every patient require tooth replacement? When should an interim prosthesis be provided?

The exact requirements will vary from patient to patient, depending on individual preferences, pattern of tooth loss, restorative status of teeth and periodontal maintainability. Wherever feasible, tooth retention should be prioritized. This offers many strategic advantages, particularly in reducing the required longevity of complex restorations.⁶

An interim prosthesis can be of great use in replacing functionally/aesthetically important teeth, improving patient comfort, reducing the impact of secondary occlusal trauma and in providing stable occlusal stops. The decision on when interim prostheses should be made is on a case-by-case basis. Prostheses should only be provided following the completion of step 1 of the clinical practice guidelines. This encompasses risk factor identification and modification, patient education, oral hygiene instruction and supra-gingival professional mechanical plaque removal.

Ideally, the optimal time to provide an interim prosthesis is following the completion of step 2 of the clinical practice guidelines, following subgingival professional mechanical plaque removal and a subsequent re-evaluation of the patient's response to treatment (Figure 2).

Design principles

It goes without saying that in patients with a high susceptibility to periodontitis, any restoration/tooth replacement should be designed with adequate access for self-performed oral hygiene and professional mechanical plaque removal. Any restorations should allow for access for interdental cleaning aids (floss/interdental brushes), with this feature being prioritized over avoiding concerns about food impaction in embrasure spaces.

The effectiveness of the design features of the interim restoration should be verified alongside an objective review of any abutment teeth, prior to transitioning to a definitive prosthesis, when the patient should have stable disease.

Case type 3: patients with stage IV periodontitis where tooth preservation is feasible with one or more tooth-delimited gaps (bounded saddles) and adequate periodontal support

Such cases represent a common finding in day-to-day practice. Depending on the quality of abutment teeth, replacement of teeth with implants, bridgework or partial dentures are all feasible.

The efficacy of bridgework was evaluated by Montero et al⁶ in a systematic review. In total, 1037 prostheses were assessed, comprising 3186 abutment teeth with a follow-up time of up to 425 months. The incidence of abutment loss was low, with 17 teeth being lost. The weighted mean incidence of prosthesis failure was also low at 6.9%. In seven studies, which included questionnaire data relating to patient satisfaction, more than 85% of patients were satisfied with the treatment provided.

With regards to bridgework. It is the opinion of the author that it should only be considered for small edentulous spaces (1–2 units), and ideally only as a definitive replacement when the endpoints of periodontal treatment have been met. The quality of the abutment teeth is important and ideally they should be minimally restored, vital teeth with low grades of furcation involvement and mobility. In terms of bridge design, minimally invasive resin-bonded designs should be considered (Figure 3).

The efficacy of removable partial dentures was evaluated by Gotfredsen et al⁷ in a systematic review. Owing to the lack of reporting of Kennedy classification (to determine whether the dentures were replacing bounded saddles), only four studies were included in the review, assessing up to 234 prostheses with up to 5 years follow-up. Abutment tooth failure (restoration/tooth loss) was reported as being between 16% and 48%, although a specific failure rate could not be attributed to a particular Kennedy classification or type of denture.

With regards to removable prostheses, it is the opinion of the author that acrylic prostheses should be considered as an appropriate interim means of replacing multiple teeth or large edentulous spans for functional and aesthetic reasons. In the anticipation of post-extraction alveolar bone remodelling and recession, the denture should be designed with occlusal rest seats where possible to prevent the displacement of the denture into the soft tissues and potential trauma to the periodontal tissues/teeth. A minimum of 2–4 abutment teeth with a good prognosis and wide anterior-posterior spread should be considered. Relining of the denture base during the healing period is recommended (Figure 4).

Depending on the restorative status of the abutment tooth, different retentive elements may be selected. Minimally/unrestored teeth are best restored with clasps, supported by occlusal rests with adequate reciprocation. Decayed or heavily restored teeth are best restored with telescopes/crowns with rest seats/clasps incorporated into their design. In heavily broken-down root-treated teeth, a post with retentive element is an appropriate design to retain the denture as an overdenture.

Case type III: stage IV periodontitis with unilateral/bilateral free-end saddles

Kennedy class I and II edentulous spaces represent increased challenges when considering tooth replacement. The lack of distal abutment reduces the retention and support of any prostheses. Furthermore, uneven displacement of the denture into the compressive supporting tissues can lead to the rotation of the prosthesis around the terminal abutment, reducing stability and theoretically leading to an increased risk of damaging the abutment teeth.

Given this, consideration must be given to the necessity for tooth replacement. The shortened dental arch concept was described by Kayser⁸ in a series of papers. The shortened dental arch is described as one with a reduced number of occlusal units, where an occlusal unit is defined as a pair of antagonist teeth that support the occlusion. In simple terms, effort is made to preserve premolar/molar teeth without the replacement of missing posterior teeth. Conventionally, a shortened dental arch is considered to encompass patients with at least 10 occlusal units extending from second premolar to second premolar.

In an appraisal of systematic reviews,^6,7,9 patients with a shortened dental arch were shown to have a reduced incidence of tooth loss compared to patients with removable partial dentures. Lower plaque/gingival inflammation was also observed when compared to patients with removable partial dentures. It represents perhaps the most economical means of managing patients with stage IV periodontitis with many patients not experiencing reduced chewing efficiency, nutritional quality and overall satisfaction when compared to those who seek replacement of molar teeth.¹⁰

Removable partial dentures showed abutment tooth failure (loss or restoration/tooth) of 9–48%. Studies have shown a higher risk for tooth loss in patients with partial dentures than those who did not have treatment. Partial dentures do not necessarily improve chewing efficiency, nutritional status, and other markers of quality of life when compared to shortened dental arch patients (Figure 5).

Case type IV: partially edentulous patients who need to be restored with full-arch fixed prostheses

A systematic review by Tomasi et al¹¹ assessed the efficacy of full-arch tooth-supported prostheses. Seven studies including 522 patients were analysed. The overall reported rates of tooth loss and loss of restoration was low (<5%). A high rate of patient satisfaction was reported.

Providing full-arch tooth-supported prostheses is technically very demanding for both the clinician and dental technician. It may not be suitable for patients who are lacking lip support, have a high smile line or where the abutment teeth have substantial recession. The cost of such treatment is high and may be out of reach for many patients. Equally, the necessity for patients to demonstrate a commitment to having excellent oral hygiene and to be compliant with attending frequent supportive periodontal therapy appointments can be challenging.

Case type IV: patients with a compromised dentition requiring tooth-supported full-arch removable prostheses

A systematic review by Donos et al¹² assessed the efficacy of tooth supported removable prostheses. A total of 22 studies were included, encompassing 4579 abutment teeth and 1660 prostheses. The included prospective studies reported tooth survival rates from 86% to 100%. There was a great degree of heterogeneity in the reporting of outcomes.

In a similar vein to full-arch tooth-supported prostheses, the successful execution of treatment is technically demanding, with associated high costs (Figure 6).

Summary and key points

Stage IV periodontitis represents a substantial challenge to clinicians and patients alike (Figure 7). According to the BSP Referral policy and parameters of care document,¹³ such patients would come under the level 3 complexity category, indicating that a referral to a specialist is recommended following initial non-surgical therapy and modification of risk factors.

The EFP clinical practice guidelines for the rehabilitation of patients with stage IV periodontitis summarizes a body of evidence that can aid decision-making when managing patients. The systematic reviews used to arrive at many of the recommendations include a limited number of studies with high rates of bias and limited external validity. Nevertheless, they provide a framework that, alongside patient preferences, can be used to optimise treatment outcomes. In conclusion:

• In addition to the established means of assessing periodontitis patients as per the BSP guidelines, assessment of chewing, aesthetics, occlusion, tooth vitality and tooth mobility should be carried out.
• Careful consideration should be given to tooth-by-tooth prognosis.
• A shortened dental arch with a minimum of 10 occluding units can be functionally and aesthetically acceptable for many patients.
• Interim prostheses should be considered when functionally/aesthetically important teeth are planned for extraction. They should be provided following initial risk factor modification, oral hygiene instruction and initial supragingival professional mechanical plaque removal. In an ideal world, they should be provided following the completion of subgingival professional mechanical plaque removal.
• In most cases, removable prostheses represent the most appropriate interim prosthesis.
• All restorations should be carefully designed with the goal of optimising self-performed plaque removal.
• Removable prosthesis should be designed with occlusal rests to prevent its displacement into the soft tissues, with 2–4 abutment teeth and wide anterior-posterior spread.
• The provision of bridgework can be considered for small tooth-delimited (bounded) gaps when good-quality abutment teeth are present. Bridgework should be designed to be minimally invasive where possible. Distal cantilevers are not recommended.
• The provision of full-arch removable and fixed tooth-supported bridgework represent technically demanding interventions. Interdisciplinary management is often necessary to deliver such treatment.