Periodontics-prosthesis interrelationship
Introduction: The environment of the tooth – the periodontium – is concerned by most of the acts performed in operative dentistry and prosthetics. A purely mechanistic approach is often encountered, neglecting the biological aspect: a certain number of imperatives must be respected, at the risk of inducing periodontal disease on an initially healthy terrain. Prosthetic treatment can only be initiated with full knowledge of the individual prognosis of each tooth after periodontal treatment.
Dental restorations and periodontal health are closely related, periodontal health is necessary for the proper function of all restorations, and the functional stimulation provided by dental restorations is essential for the preservation of the periodontium. The word “restorative” in the term restorative dentistry refers primarily to the restoration of occlusion, not only for the teeth to be restored and their antagonists, but also for the rest of the dentition. This is why dental restorations are as much a part of the treatment of periodontal disease as scaling and curettage and surgical procedures.
1-Definition of prosthesis: the Robert dictionary defines the word “prosthesis” as follows: replacement of a limb organ (in whole or in part) by artificial devices.
Periodontics-prosthesis interrelationship
A dental prosthesis is nothing more than an “artificial device” to be integrated into an organism. The artificial element must therefore fulfill its own function and respect as much as possible the organism that receives it.
2-Goals of prosthetic restoration : dental prosthesis has two main purposes: to restore masticatory function and to ensure aesthetics.
In addition to these functional and aesthetic objectives common to all fixed restorations, the tooth-supported prosthesis on reduced periodontium must specifically respect the periodontal environment, aesthetically compensate for tissue loss, harmoniously distribute the occlusal load on the supporting teeth and sometimes contain the latter.
-Respect for the tissue environment : periodontitis leads to attachment loss and significant alteration of the peridental anatomical structures. Periodontal treatment aims to stop attachment loss and possibly optimize attachment gain, while periodontal monitoring aims to prevent relapses and therefore maintain the attachment level at the post-treatment level in the long term. Given the importance of good individual plaque control during periodontal monitoring, one of the first prosthetic objectives will be to allow 360° access to the soft tissue-hard tissue junction around each tooth.
-Contention : the rigidity provided by the prosthetic framework makes it possible to distribute the stresses exerted on the prosthesis to all the residual roots and to participate in the reduction of micromovements of the dental roots to the most reduced periodontium. This dissipation of stress has the effect, on the most mobile teeth, of improving patient comfort by reducing/eliminating mobility perceived as excessive.
-Aesthetics : very open interdental spaces associated with unsightly black triangles, long teeth and secondary dental migrations are the most frequent aesthetic complications of treated periodontitis. These complications are directly linked to the reduction in the level of attachment linked to the disease and to the periodontal recessions that frequently accompany the healing of the attachment system. The aesthetic analysis must take these diagnostic elements into account in order to anticipate the prosthetic correction. The aesthetic indication is mainly based on the well-being and demand of the patients, because it is not in itself therapeutic. It must therefore not be constrained by the major functional principles of maintaining the teeth on the arch. Even if, strategically, periodontally conserveable teeth are extracted for prosthetic reasons, care should be taken as much as possible to preserve the teeth.
-prevention of dental tilting and extrusion.
3-Influence of periodontal status on prosthetic treatment:
1-In the presence of moderate periodontitis, no periodontal reason requires extraction. Classic treatment followed by regular prophylaxis allows us to optimistically consider the preservation of teeth in the absence of another dental pathology.
2-In the presence of moderate or advanced periodontitis, no extraction, except in the terminal stages, is necessary. The evolution of the periodontal treatment determines the possible decision to extract. The sometimes spectacular nature of periodontal damage – pus discharge, mobility, abscess, gingival withdrawal or gingival recession – does not in itself constitute a reason to decide on extraction.
-In the event of a moderate or major periodontal problem, definitive prosthetic treatment will only be undertaken several months after periodontal treatment, in the presence of correct plaque control and healing of the various sites acquired: a safe prognosis can then be established for each abutment tooth.
-In the case of clear and progressive periodontitis, a prosthesis already proving necessary – already edentulous area, terminal alveolysis, root proximity, extensive carious lesions, irreparable endodontic lesions – the choice between fixed and removable prostheses will be conditioned among other things by the disappearance of inflammatory phenomena. This removal depends on the surfacing, possible surgery, plaque control and professional prophylaxis. For these last two points, the patient’s motivation is absolutely important.
If the inflammation persists, there is a risk of progression. The patient’s financial involvement in the fixed prosthesis will often direct the practitioner towards the creation of a partial removable prosthesis.
Periodontics-prosthesis interrelationship
During the observation period, the filling of edentulous areas will preferably be done with a temporary removable prosthesis (resin). It is impossible to predict the future, and the size of certain teeth may prove useless if a fixed prosthesis is not made.
3-In the presence of very severe generalized periodontitis, total extraction is obviously indicated. Extractions on demand with successive addition of teeth to the prosthesis will, if possible, be avoided. Indeed, the progressive nature of periodontal disease makes the conditions much more unfavorable after deferred extractions.
Periodontics-prosthesis interrelationship
4-Pre-prosthetic periodontal preparation: this phase depends on the initial oral-dental condition of the patient and is therefore subject to a preliminary clinical examination.
- Initial clinical examination : it is essential to assess:
-the patient’s level of oral hygiene
-the severity of any periodontal damage: examination of the periodontium and roots allows for an assessment of each pillar, to assess the length and shape of the roots, the bone trabeculations, the lamina dura, the presence or absence of infrabony pockets. It allows for the distribution of dental and mucosal supports without risk to the remaining teeth, information that a plaster model does not provide.
-the integrity of the endodontium and the value of the endodontic and prosthetic care carried out previously
-the functional integrity of the masticatory system
The parameters to be considered during this observation will be (LINDHE and NYMAN 1977):
-presence of dental plaque and tartaric deposits
-gingival inflammation
-presence of periodontal pockets
– presence of interradicular alveolysis
-dental mobility
-level and configuration of the alveolar bone crest
The periapical state of the dental organs present and the possible presence of fillings or iatrogenic prosthetic elements.
On the functional level, it will be necessary to examine the state of the masticatory system and the pathological signs of a possible dysfunction:
-dental wear facet
-examination of the temporomandibular joints
-examination of mandibular movements and occlusal function
-examination of the masticatory muscles
Periodontics-prosthesis interrelationship
- Patient motivation : the presence of bacterial deposits should first be highlighted using a revealing solution and scaling should be performed. The practitioner should teach the patient a hygiene technique using brushing and adjuvants. The aim of this motivation phase is to eliminate marginal inflammation in order to prevent gingival bleeding during prosthetic preparation and impression making and to eliminate the false pocket in order to restore a more physiological marginal gingival limit. Depending on the patient’s cooperation, pre-prosthetic periodontal treatment is then undertaken or a less conservative treatment is considered.
- Extraction of irretrievable teeth
- Care and treatment of decayed teeth
- Indication for temporary retention : when dental mobility is too significant (Muhleman class III), immobilization of the most affected dental organs is necessary even before the scaling session in order to make this procedure more comfortable. It should be noted that when periodontal surgery is planned for mobile teeth, temporary retention promotes the postoperative healing process.
- Occlusal aspects : prosthetic restoration plays an important role in the reestablishment or preservation of harmonious occlusal relationships: by replacing missing teeth and therefore stabilizing intra-arch and inter-arch relationships, by maintaining a vertical dimension of occlusion and a centric relationship allowing physiological functioning of the masticatory system. However, it will sometimes be necessary to perform a certain number of occlusal corrections during the pre-prosthetic phase: Reestablish a physiological occlusion plane, eliminate premature contacts or possible occlusal interferences, reestablish a vertical dimension of occlusion and/or a centric relationship.
Occlusal trauma must be eliminated before restorations are started, and restorations must be constructed in accordance with the newly established occlusal forms. If this is not done, the prosthesis reproduces occlusal relationships that are harmful to the periodontium. The harmful effects of occlusal trauma are not limited to the teeth involved in the restoration and their antagonists. Other regions of the dentition are affected secondarily, through occlusal disharmony. Occlusion must be checked regularly after insertion of the prosthesis. Occlusal relationships change over time as a result of wear of the restorative materials and settlement of tissues covered by the saddles of removable prostheses, especially those without distal support.
- Elimination of periodontal pockets : the aim of surgical treatment (curettage, gingivectomy, mucoperiosteal flap, hemisection, root amputation) is to reduce the depth of the gingivodental sulcus to between 2 and 2.5 mm maximum. Beyond this depth, it is no longer possible for the patient to control the subgingival bacterial plaque, which can potentially cause a worsening of the periodontal condition and can thus compromise the durability of the prosthetic restoration.
- Correction of mucogingival defects : Mucogingival defects such as the absence of attached gingiva or the presence of gingival recessions must be corrected during pre-prosthetic periodontal preparation. The goals of pre-prosthetic mucogingival surgery are:
-restore a harmonious gingival contour
-create or recreate around the future elements an area of adherent gingiva opposing any traction of the alveolar mucosa at the level of the marginal gingiva and to avoid any risk of gingival recession. Frenectomy, covering of periodontal recessions, increasing the height of the attached gingiva, vestibuloplasty and coronal elongation are surgical techniques that can be performed before the prosthetic restoration in order to facilitate the integration of the prosthetic restorations.
Periodontics-prosthesis interrelationship
- Patient reassessment: After periodontal surgery, it is advisable to check the continuity of bacterial deposit control and to check the condition of the periodontal tissues before considering the prosthetic phase (depth of the gingival-dental grooves, condition and contour of the marginal gingiva, height of the adherent gingiva). Depending on the results obtained after healing (2 to 4 months), the necessary dental extractions are carried out and the definitive prosthetic treatment plan determined.
5-Imperatives to be respected when making the fixed prosthesis:
Normal periodontium : the fixed prosthesis is made after a classic initial periodontal preparation: instructions for plaque control and scaling.
1 – Attached gingiva and gingival recessions: regardless of the location, the appearance of a recession after fitting a fixed prosthesis is also difficult for the patient to accept. The way to avoid this appearance, in the absence of attached gingiva or low height, consists of a muco-gingival intervention carried out before the prosthetic phase. In the presence of already established gingival recession, particular attention is paid to the cervical limit of the preparation.
2 – Limits of preparations: the limits must be para-gingival or supra-gingival: this is now unanimously recognized. Indeed, the joint between any restoration, even perfect, and the tooth is never watertight. A solution of continuity always exists. In addition, the porosity of all materials is noted as a retention factor for bacterial plaque. The root zone located under the filling must imperatively remain accessible to hygiene, whatever the material used.
3 – Gingival embrasure: in the case of the creation of single elements, the interdental papilla must never be compressed. Plaque control can be carried out using interdental floss or an interdental brush.
4 – Interdental elements:
a-Respect for interdental embrasures: sufficient space for the passage of an interdental stick or, better, a brush.
b-Respect for the prosthetic space of the edentulous crest: care must be taken to ensure that the laboratory does not scratch the model at the level of the edentulous crest, so as to avoid, after sealing, the appearance of inflammatory reactions which are often proliferative and rarely favorable to good prophylaxis.
c-Morphology of edentulous ridges: it is not always compatible with the design of a rational bridge. The observation of this is often neglected by the practitioner in his pre-prosthetic study.
Periodontics-prosthesis interrelationship
Two situations may arise:
-The crest is too high, preventing the creation of intermediate elements of correct height and shape. Mucosal thinning can reduce the height of this crest. If necessary, it will be supplemented by osteoplasty of the bony crest. Apical repositioning of the crest remains possible in the event of a lack of attached gingiva, which avoids irritation by traction.
– the ridge is collapsed, the defect can be filled in several ways: connective tissue graft, bone graft or synthetic materials, guided bone regeneration. Some use an epithesis (false gum made of resin or silicone)
5 – Pontics (bridge intermediaries): a pontic must meet the following requirements:
-it must be aesthetic
-provide favorable occlusal relationships to the abutment teeth and opposing teeth as well as to the rest of the dentition.
-restore the effectiveness of the masticatory function of the tooth it replaces
-be designed to minimize the accumulation of plaque and irritating food debris and allow maximum access for the patient to clean their teeth
-create openings for the passage of food
5 – occlusion: failure to respect occlusal relationships can lead, in addition to pathologies at the level of the temporomandibular joint, to periodontal problems if poor plaque control, with or without iatrogenic prosthetic restoration, has previously induced marginal periodontitis.
6 – Temporary elements: special attention must be paid to respecting the contact points and the vestibulo- lingual anatomy in order to avoid food jamming. Whenever possible, elements made of thermopolymerizing resin, made in the laboratory, should be preferred to those made of self-polymerizing resin, made in the chair, because of better resistance and less porosity.
7 – Impression: the production of the master model requires the most precise impressions possible. Whatever the technique, it is facilitated by working supragingivally. A classic difficulty of subgingival preparations lies in the need to cause mechanical retraction of the marginal gingiva by a cotton thread impregnated or not with vasoconstrictor agents, to open the gingival sulcus with an electric scalpel or to use a juxta-ligamentary copper ring. All these methods cause gingival lesions of varying importance, and generally without great severity as long as we are on healthy gingiva. On inflamed tissue, the reactions are difficult to control.
8 – Sealing: a systematic search for cement rockets in the subgingival region is essential. The control is carried out with a probe. Supra or para gingival limits obviously facilitate the task.
9 – Axes of the second molars: a classic sequela of premature extraction of the first molars, while the second molars are erupting, is their mesioversion with creation of pseudo periodontal pockets in the mesial (difficult prophylaxis in this area) and appearance of premature contacts responsible for mesial periodontitis in the event of gingival inflammation. Pre-prosthetic orthodontic straightening of the second molars is then desirable, both on the periodontal and occlusal and prosthetic level.
10 – Aesthetics: Aesthetic requirements often make it necessary to prepare para- or slightly subgingival crowns. A valid and lasting aesthetic result is only possible if, before the impressions, the marginal periodontium is free of inflammation. Aesthetic reasons sometimes make pre-prosthetic preparation by periodontal surgery necessary, for example if one wants to lengthen a crown or harmonize an incisor-canine block. In this case, apical repositioning techniques are used, most often in partial thickness. Ridge corrections by thinning or filling are also sometimes useful for aesthetic purposes.
6-Imperatives to be respected when making a removable prosthesis : from a periodontal point of view, the fixed prosthesis is the restoration of choice, but a removable partial prosthesis is also very effective. Its usefulness in the total treatment of periodontal problems should not be minimized.
Form : To provide maximum stability to removable partial dentures , care should be taken to retain as many of the posterior teeth as possible to provide distal support at the saddles.
Hooks : Hooks must be designed to be passive; that is, they must not exert any pressure or tension on the abutment teeth when the prosthesis is at rest.
Periodontics-prosthesis interrelationship
Occlusal supports : the shape of the occlusal supports must allow them to direct the forces along the vertical axis of the tooth .
7-Position of prosthetic limits : the interaction zone between the prosthesis and the periodontium is made up of the sulcular space and the attachment system of the tooth. Although it is not biologically necessary to place the prosthetic limits intrasulcularly or subgingivally, this may prove aesthetically essential. These limits are acceptable, provided that they do not encroach on the connective tissue attachment and that perfect prosthetic adaptation is obtained. On the other hand, the penetration of a prosthetic element apically to the epithelial attachment is considered a violation of the biological space. The connective tissue attachment is then mechanically and chronically attacked by the prosthetic element and possibly by the sealing cement, which is often practically impossible to eliminate completely. The initial reaction will be inflammatory and will only be reduced by the natural remodeling of the tissues in the apical direction. It is clinically appropriate to perform a periodontal probe with a manual pressure of 0.2 Newton and not to place the limits beyond the value indicated by the probe. In fact, at this pressure the tip of the probe does not penetrate beyond the most coronal fibers of the connective tissue attachment.
- Juxta- or supragingival limit : All prosthetic limits located on the tooth at or above the marginal gingiva are defined as juxta- or supragingival.
The supragingival limit is the biological limit of choice in restorative dentistry and can very well be used on a reduced periodontium. It is a periodontally ideal limit because it does not interfere at any time with the biological space. It is often feasible because the reduction of the periodontium apically displaces the prosthetic limits.
Periodontics-prosthesis interrelationship
Advantages of supragingival margins :
-improved accessibility to plate control
– less damaging preparation due to the axial depth and height of the preparations which will be reduced. The fact of descending less apically along the root allows the tooth to be prepared in an area of wider contour.
– possibility of recording the impression without using the gingival retraction wire when the supragingival preparation is more than 1 mm from the marginal gingiva (no trauma to the attachment system).
-increase in the quality of practitioner control during fittings and sealing.
The supra- and juxtagingival limits must be carefully decided in full agreement with the patient (unaesthetic). They are addressed to the mandible and the maxillary posterior sectors.
The absence of root discoloration will be checked and the labial coverage of the cervical limits will be ensured during natural and forced movements of the lips, particularly when smiling.
Periodontics-prosthesis interrelationship
The presence of pre-existing subgingival carious lesions constitutes a contraindication to this type of preparation.
- Intrasulcular limits : it is possible to follow a subgingival prosthetic limit without inflammatory consequences. The indications for such limits can be aesthetic, most often in the anterior areas, or aim to mechanically increase the retention of restorations.
The clinical elements that may lead to the choice of a subgingival limit for aesthetic purposes are a visible tooth-gum limit when smiling, unsightly root discolorations and, more simply, the patient’s desire not to see prosthetic areas appear, such as metal bands. However, intrasulcular limits have consequences on the prepared teeth. They require the extension of the preparations in length and depth, the complication of the preparation, impression, fitting and sealing procedures, and finally they lead to greater weakening of the teeth compared to supra- and juxtagingival preparations.
Periodontics-prosthesis interrelationship
Periodontally, subgingival limits extending beyond the base of the sulcus can cause tissue trauma at each clinical stage.
Conclusion : The progression of periodontal disease very often condemns a certain number of dental organs and reduces the quality of the periodontal support of the preserved teeth. When we know that this periodontal disease is the main cause of tooth loss, a high percentage of prosthetic reconstruction applies to patients with a weakened periodontium, which confirms the fact that increasingly close therapeutic relationships must be established between periodontics and prosthesis.
Periodontics-prosthesis interrelationship
Bibliography:
-HAS. DANIEL, B.GIUMEL THE EMC periodontal prosthesis (Paris, France) stomatology II, 23604 E 1-19 1985 15p
-Bercy .Tenenbaum periodontology from diagnosis to practice De boeck-University
-J.-J. BARRELLE, P.GENON, S.ROZANES, T.SANDOT periodontal prosthesis EMC 23604 E 10-12-1975
-Philippe Bouchard periodontology Implant dentistry Volume 1-Periodontal medicine
Periodontics-prosthesis interrelationship
Cervical limits