Waerhaug J The gingival pocket. Anatomy pathology deepening and elimination. Odontol Tidskr. 1952; 60:1-186
Nugala B, Santosh Kumar BB, Sahitya S, Krishna PM Biologic width and its importance in periodontal and restorative dentistry. J Conserv Dent. 2012; 15:12-17
Makigusa K Histologic comparison of biologic width around teeth versus implant: The effect on bone preservation. J Implant Reconstr Dent. 2009; 1:20-24
Gargiulo AW, Wentz F, Orban B Dimensions and relations of the dentogingival junction in humans. J Periodontol. 1961; 32:261-267
Ingber JS, Rose LF, Coslet JG The “biologic width”-a concept in periodontics and restorative dentistry. Alpha Omegan. 1977; 70:62-65
Waerhaug J The angular bone defect and its relationship to trauma from occlusion and downgrowth of subgingival plaque. J Clin Periodontol. 1979; 6:61-82
Waerhaug J The infrabony pocket and its relationship to trauma from occlusion and subgingival plaque. J Periodontol. 1979; 50:355-365
Jorgic-Srdjak K, Plancak D, Maricevic T, Dragoo MR, Bosnjak A Periodontal and prosthetic aspect of biological width part I: Violation of biologic width. Acta Stomatol Croat. 2000; 34:195-197
Rosenberg ES, Cho SC, Garber DA Crown lengthening revisited. Compend Contin Educ Dent. 1999; 20:527-538
Nevins M, Skurow HM The intracrevicular restorative margin, the biologic width, and the maintenance of the gingival margin. Int J Periodont Rest Dent. 1984; 4:30-49
Newcomb GM The relationship between the location of subgingival crown margins and gingival inflammation. J Periodontol. 1974; 45:151-154
Tal H, Soldinger M, Dreiangel A, Pitaru S Periodontal response to long-term abuse of the gingival attachment by supracrestal amalgam restorations. J Clin Periodontol. 1989; 16:654-659
Gunay H, Seeger A, Tschernitschek H, Geurtsen W Placement of the preparation line and periodontal health – a prospective 2-year clinical study. Int J Periodontol Rest Dent. 2000; 20:171-181
Richter WA, Ueno H Relationship of crown margin placement to gingival inflammation. J Prosthet Dent. 1973; 30:156-161
Gracis S, Fradeani M, Celletti R, Bracchetti G Biological integration of aesthetic restorations: factors influencing appearance and long-term success. Periodontology 2000. 2001; 27:29-44
Wilson RD, Maynard G Intracrevicular restorative dentistry. Int J Periodontol Rest Dent. 1981; 1:(4)35-49
Tarnow D, Stahl SS, Magner A, Zamzock J Human gingival attachment responses to subgingival crown placement marginal remodeling. J Clin Periodontol. 1986; 13:(6)563-569
Galgali SR, Gontiya G Evaluation of an innovative radiographic technique-parallel profile radiography – to determine the dimensions of dentogingival unit. Indian J Dent Res. 2011; 22:(2)237-241
In: Chiche GJ, Pinault A (eds). Chicago: Quintessence Publishing; 1994
, 3rd edn. In: Shillingburg HT, Hobo S, Whitsett LD, Jacobi R (eds). Chicago: Quintessence Publishing Co Inc; 1997
Ferrari M, Cagidiaco MC, Erocli C Tissue management with a new gingival retraction material: a preliminary clinical report. J Prosthet Dent. 1996; 75:(3)242-247
Yuodelis RA, Faucher R Provisional restorations: an integrated approach to periodontics and restorative dentistry. Dent Clin North Am. 1980; 24:(2)285-303
Yuodelis RA, Weaver JD, Sapkos S Facial and lingual contours of artificial complete crown restorations and their effects on the periodontium. J Prosthet Dent. 1973; 29:(1)61-66
Hirschfeld I Food impaction. J Am Dent Assoc. 1930; 17:1504-1528
Bral M Periodontal considerations for provisional restoration. Dent Clin North Am. 1989; 33:(3)457-475
Sotres LS, Van Huysen G, Gilmore HW A histologic study of gingival tissue response to amalgam, silicate and resin restorations. J Periodontol. 1969; 40:(9)543-546
Swartz ML, Phillips RW Comparison of bacterial accumulation on rough and smooth surfaces. J Periodontol. 1957; 28:304-307
Senior Lecturer, Department of Conservative Dentistry and Endodontics, Institute of Dental Studies and Technologies, Modinagar, Ghaziabad, Uttar Pradesh, India
Today's dentistry is dominated by restorative procedures which are carried out to meet the demands of not only function but also aesthetics. Prosthetic and restorative therapies generally require a healthy periodontium as a prerequisite for successful treatment outcome. A mouth with a healthy periodontium may be affected by restorations of poor quality, and restorations of the highest quality may fail in a mouth with periodontal disease. This is the first of two articles that attempt to explain the concept of the complex question of biologic width and the problems that occur after improper margin placement in the periodontium. Initially, the dimensions of biologic width are considered and then margin placement and reasons for restorative procedures are discussed. This article also addresses the interactions between periodontal tissues and restorative procedures.
Clinical Relevance: Understanding the impact of restorative procedures on periodontal health in regular dental examination by dentists can help in early diagnosis and treatment of periodontal diseases. This could prevent further progression of disease and reduce the frequency of tooth loss.
Article
Periodontal tissues form a strong basis for both aesthetics and comfort of the dentition as well as the functioning of dental tissues.1 The interrelationship of restorative dentistry and periodontics is a dynamic one.2 The periodontal health at the restorative gingival interface represents a big challenge for the restorative dentist, as the tooth and its surrounding structures are continuously being affected by microbial flora, and restorative dentistry may aggravate this condition.3
Prosthetic and restorative treatments generally require a healthy periodontium as a prerequisite for successful outcome, and this interaction between two important fields of dentistry is present on many fronts, including placement of restorative and crown margins, and contours of the crown, and the response of the gingival tissues to restorative preparations.1
Periodontal attachment loss begins when the epithelial integrity of the dentogingival unit is breached by microbial flora, trauma, or both. The progression of the periodontal destruction appears to be related to host susceptibiity, competence of the surrounding tissues, and virulence factors of bacterial pathogens,4,5 which in turn may be influenced by the three main aspects of a dental restoration: morphology, margin quality and margin location.3
Glickman6 has rightly stated that every restoration has a periodontal dimension. A mouth with a healthy periodontium may be affected by restorations of poor quality, and restorations of the highest quality may fail in a mouth with periodontal disease. It is important that the restorative phase of dental treatment is commenced keeping in mind the periodontal health status of the patient and only when the patient has learned to maintain that health.7 The practice of restorative dentistry has a reciprocating interrelationship with the maintenance of periodontal health. Undiagnosed and untreated periodontal disease may compromise the success of restorative dentistry, and poor restorative treatment may have adverse effects on the periodontium by increasing the accumulation of plaque and inducing changes in the composition of the microbial flora. The successful integration of periodontal and restorative dentistry for both natural teeth and implants requires knowledge and the application of both mechanical and biological principles.8 The proper location of the restorative and crown margins relative to the alveolar bone height may be one of the most important parameters to ensure long-term gingival health, as the restorations that interfere with host defences will create sites where micro-organisms thrive and cause destruction.9
Successful restorative dentistry can be best accomplished when healthy and stable tissues surround the teeth or their implant replacements and, by evaluating both soft and hard tissues around teeth and implants before, during and after restorative procedures, the probability of a successful outcome will be greatly increased.8
This is the first of two articles that emphasizes the restorative considerations of periodontal disease, and covers the factors important in operative dentistry and prosthetics for the maintenance of periodontal health. In this part, the biologic considerations during crown placement and the way these may damage the periodontal tissues are described and the various other restorative aspects that may damage the periodontal tissues are also covered.
The second part of the article will include the surgical techniques for correction of biologic width, correction of interproximal embrasure form, crown preparation, pontic design, splinting and some of the special cases, like the restoration of a root resected or a bicuspidized tooth, root caries or external resorption cases leading to periodontal tissue damage.
Importance of preparation of the periodontium for restorative dentistry
Periodontal disease is a multifactorial, polymicrobial and polygenic disease with variable clinical features, with the primary aetiological agent being the specific bacterial pathogens. Supragingivally, local factors like crowding, calculus and rough unpolished restorations act as plaque retentive areas leading to host response in the form of gingival inflammation and/or gingivitis.
When allowed to progress, the Gram-negative anaerobes flourish and any irregularities like root anatomy, subgingival restorative margins and overhanging dental restorations will enhance bacterial adhesion to the pocket epithelium and the tooth surface, thus allowing the growth of subgingival plaque.10
The reasons why periodontal disease should to be eliminated prior to restorative dentistry are:11,12
To locate and determine the gingival margins of restorations properly; the position of the healthy and stable gingival margin must be established prior to tooth preparation. Margins of restorations covered by inflamed gingiva shrinks after periodontal treatment.
The position of the tooth may be altered in periodontal disease. Resolution of inflammation after treatment causes the tooth to move again, often back to its original position.
Restorations designed for teeth before the periodontium is treated may produce injurious tensions and pressures on the treated periodontium.
Inflammation of the periodontium impairs the capacity of abutment teeth to meet the functional demands made on them.
Discomfort from tooth mobility may interfere with mastication and function.
It is easier to obtain accurate impressions and make more precise preparations on healthy gingivae than inflamed ones.
To minimize the risk of trauma to the gingival tissues during preparation and impression procedures.
Restorative dentistry has an effect on the periodontal health in many ways, which include the type of restorative material, the way in which it is placed, and the contour of the restoration.3,13 The degree of retention of plaque is an important factor; for example, the subgingival margins of the restorations and crowns, the fit of dentures and bridges, the contour and materials of the restorative material.14 Also, if subgingival restorations are placed, they should be smooth finished if possible, formed in materials unlikely to deteriorate under plaque and, ideally, retard plaque formation.14 Efforts should be made to gain access to subgingival lesions by the use of small localized flaps,15 to provide access, vision and proper adaptation and finish to the restoration.16
Extra care is required for various procedures on the tissues, like the placement of matrix bands, interdental wedges, rubber dam, rubber dam clamps and temporary restorations. Clinicians also need to consider the length of time a restoration has been defective, and be mindful of a gingival inflammation suddenly becoming a destructive periodontal lesion.3
Many attempts have been made to improve both techniques and materials to meet the ever-increasing aesthetic requirements of patients. However, too often the emphasis is placed on these factors as the only keys to success. It is instead the integration of a natural-looking prosthesis within a healthy periodontium that should represent the ultimate goal of the treatment, emphasizing the restorative materials and clinical procedures that play a role in any clinician's attempt to create biologically acceptable and aesthetically pleasing long-lasting restorations.
Biologic considerations during crown placement, restorative margin location and implications for soft tissue stability
Concept of biologic width
In the human body, an ectodermal tissue serves to protect against invasion from bacteria and other foreign materials. However, both teeth and dental implants must penetrate this defensive barrier.17 The natural seal that develops around both, protecting the alveolar bone from infection and disease, is known as the biologic width.18 The biologic width is defined as the dimension of the soft tissue which is attached to the portion of the tooth coronal to the crest of the alveolar bone (Figure 1). This term was based on the work of Gargiulo et al,19 who described the dimensions and relationship of the dentogingival junction in humans. Measurements made from the dentogingival components of 287 individual teeth from 30 autopsy specimens established that there is a definite proportional relationship between the alveolar crest, the connective tissue attachment, the epithelial attachment, and the sulcus depth. Gargiulo et al19 reported the following mean dimensions: a sulcus depth of 0.69 mm, an epithelial attachment of 0.97 mm, and a connective tissue attachment of 1.07 mm. Based on this work, the biologic width is commonly stated to be 2.04 mm, which represents the sum of the epithelial and connective tissue measurements.1 In 1977, Ingber et al20 described ‘Biologic width’ and credited D Walter Cohen for first coining the term. The basis for the biologic width is the so-called ‘radius of inflammatory effect’ in which there is a finite distance of approximately 1–2 mm over which the tissue lytic properties of localized inflammation operate.21,22
Figure 1. Biologic width composed of junctional epithelium and connective tissue attachment.
The biologic width is essential for preservation of periodontal health and removal of injurious factors that might damage the periodontium. The dimension of biologic width is not constant. It depends upon the location of the tooth in the alveolus, varies from tooth to tooth, and also from the aspect of the tooth. It has been shown that 3 mm between the preparation margin and alveolar bone maintains periodontal health for 4–6 months.23 This 3 mm constitutes 1 mm supracrestal connective tissue attachment, 1 mm junctional epithelium and 1 mm gingival sulcus, on average. This allows for adequate biologic width even when the restorations margins are placed 0.5 mm within the gingival sulcus.24
Nevins and Skurow stated that biologic width should be maintained during tooth preparation and impression taking, and also the subgingival margin extension should be limited to 0.5–1 mm, because it is impossible for the clinician to detect where the sulcular epithelium ends and where the junctional epithelium begins.25
Margin placement and biologic width
Placing restorative margins within the biologic width frequently leads to gingival inflammation, clinical attachment loss and alveolar bone loss (Figures 2 and 3). This is thought to be due to the destructive inflammatory response to microbial plaque located at deeply placed restorative margins encroaching on the biologic width. This may further progress and lead to formation of pockets and also recession.1,26,27
Figure 2. (Case 1) Subgingival restorative margin within biologic width leading to gingival inflammation in relation to UL1. (a) Fractured UL1. (b) Gingival inflammation and discoloration in UL1 after crown placement.Figure 3. (Case 2) Subgingival restorative margin within biologic width leading to gingival inflammation in relation to UL1.
In a 2-year study, Gunay et al28 compared 116 prepared teeth to 82 unrestored healthy teeth in 41 patients and concluded that restorative margin placement within the biologic width was detrimental to periodontal health with maximum increase in papillary bleeding score and probing depth measurements at sites where the restorative margin was <1 mm from the alveolar crest.1
While many clinicians prefer to place restorative margins subgingivally, the detrimental effects of margins below the free gingival margin is well documented. While most periodontists prefer restorative margins to remain coronal to the sulcus, it is understood that certain conditions necessitate placement of subgingival margins. These may include aesthetic concerns, the need for increased retention form, refinement of pre-existing margins, root caries, cervical abrasion and root sensitivity. However, if none of these factors is of concern, it appears prudent to place restorative margins supragingivally1 (Figure 4).
Figure 4. Supragingival restorative margin in UL5 and UL6.
In addition, the location of restorative margins is determined by many factors, including aesthetics, retentive factors, susceptibility to root caries, and degree of gingival recession.
When determining where to place restorative margins relative to the periodontal attachment, it is recommended that the patient's existing sulcus depth is used as a guideline in assessing the biologic width requirement for that patient.2 The base of the sulcus can be viewed as the top of the attachment and therefore variations in attachment height are accounted for by ensuring that the margin is placed in the sulcus and not in the attachment. The first step in using sulcus depth as a guide in margin placement is to manage gingival health.2 Regardless of the preparation design and its position (supra or subgingival), a precise and well-defined margin should always be the aim. According to Richter and Ueno,29 marginal fit and finish may be more significant to gingival health than the location of the margin. Ideally, the margin of a prosthetic restoration should be easily accessible for the following reasons:
To facilitate fabrication of the provisional restoration;
To facilitate impression taking, to allow assessment of the fit of the restoration;
Once the tissue is healthy, the following three rules can be used to place intra-crevicular margins.2,31
Rule I
If the sulcus probes 1.5 mm or less, place the restoration margin 0.5 mm below the gingival tissue crest. This is especially important on the facial aspect and prevents a biologic width violation in a patient who is at high risk in that regard.
Rule II
If the sulcus probes more than 1.5 mm, place the margin one-half the depth of the sulcus below the tissue crest. This places the margin far enough below tissue so that it is still covered if the patient is at higher risk of recession.
Rule III
If a sulcus greater than 2 mm is found, especially on the facial aspect of the tooth, then evaluate to see whether a gingivectomy could be performed to lengthen the teeth and create a 1.5 mm sulcus. Then the patient can be treated as mentioned in Rule I.
Depending on the thickness of the underlying bone and the dimension of keratinized gingiva, different clinical and histological responses can result from a supracrestal biological width violation. Usually, with a thick periodontium (fairly flat cement-enamel junction and gingival scallops, thick cortical plates and increased thickness of keratinized gingiva), little apical migration of the dentogingival unit and intrabony pocket formation are observed.32 Whereas in the presence of a thin periodontium (high gingival scallop, thin cortical plates and limited thickness of keratinized gingiva), gingival recession and apical migration of the dentogingival unit may instead be observed. This migration is sometimes self-limiting, as observed by Tarnow et al.33 Prominent roots need to be evaluated to identify any fenestrations or dehiscences. These conditions associated with a thin periodontium contra-indicate the placement of a restorative margin subgingivally.30
If the patient experiences tissue discomfort when the margins are being assessed with a periodontal probe, it may be considered that a violation of biologic width has occurred with the potential to lead to gingival hyperplasia, bleeding on probing, recession, bone loss and pocket formation (Figure 2).
2. Bone sounding
Biologic width can be assessed by measurement with periodontal probe to the bone level and subtracting the sulcus depth from it. If the distance from base of sulcus to bone is less than 2 mm, it is considered to be a violation of biologic width. This assessment is completed circumferentially around the tooth to evaluate the extent of the problem.
3. Radiographic measurement
Radiographic interpretation can identify interproximal violations of biologic width (Figure 5). However, with the more common locations on the mesiofacial and distofacial line angles of teeth, radiographs are not diagnostic because of tooth superimposition. A parallel profile radiographic technique has been recently described as a non-invasive, concise, reproducible and simple technique used to measure the length and thickness of a dentogingival unit.34
Figure 5. IOPA showing root canal treated UR1 and UL1 in which subgingival crown margins will lie within the biologic width.
To enhance access, so that damage to the soft tissues is prevented during crown or cavity preparation and impression taking, it may be desirable to carry out some degree of gingival retraction.2 The objective of tissue retraction is to expose all of the prepared tooth structure and, possibly, a portion of the unprepared root beyond the margin by causing a horizontal and vertical displacement of the marginal gingiva. This can be achieved by the use of gingival retraction cords. A single-cord technique is the least traumatic option and is normally employed when the sulcus is shallow and the margin is placed only minimally in the crevice. A double-cord technique is used when the sulcus is deeper. The first cord is ultrathin (000) cord, which will stay in place throughout impression taking, while the second cord is one size bigger and will be removed just before injection of impression material. From the point of view of prosthetic convenience, it may be desirable to employ this technique because it yields more extensive displacement. However, the soft tissue anatomy on the buccal aspect of the anterior teeth rarely permits two cords to be placed. In the presence of a limited facial crevice, a selective double-string technique is better, the second cord being placed only interproximally and lingually. The second cord is usually one size bigger than the first, and it is soaked to control fluid seepage and any slight bleeding. The first cord, which stays in place throughout the impression procedure, is left untreated.30
This maneouvre has two advantages: it highlights the base of the sulcus and therefore the ultimate limit of the preparation before causing irreversible damage; and it pushes the gingival margin outward and apically to expose the unprepared tooth structure to be removed better. Margin placement has to respect the attachment apparatus and to allow for some degree of error during the high-speed instrumentation.35
For a Rule 1 margin, the cord should be placed in such a way that the top of the cord is located in the sulcus at the level where the final margin will be established, which will be 0.5 mm below the previously prepared margin. On the interproximal aspects of the tooth, the cord will usually be 1–1.5 mm below the tissue height because the interproximal sulcus is often 2.5–3 mm in depth. With this initial cord in place, the preparation is extended to the top of the cord, with the bur angled to the tooth so that it will not abrade the tissue. This process protects the tissue, creates the correct axial reduction and establishes the margin at the desired subgingival level. A second retraction cord is required to create space for final impression. The second cord is pushed so that it displaces the first cord apically and is sited between the margin and the tissue. For the final impression, the top cord is removed, leaving the margins visible and accessible to be recorded with the impression material. The initial cord remains in place in the sulcus, until the provisional restoration is completed. For Rule 2 situations, where the sulcus is deeper, two larger diameter cords are used to deflect the tissue prior to extending the margin apically. The top of the second cord is placed to identify the final margin location at the correct distance below the previously prepared margin, which was at the gingival tissue crest level. The margin is lowered to the top of the second cord and then a third cord is placed in preparation for the impression.2
Various chemicals used for the treatment of cords include:2
0.1% and 8% recemic epinephrine;
100% alum solution (potassium aluminum sulphate);
5% and 25% aluminum chloride solution;
Ferric subsulphate (Monsel's solution);
13.3% ferric sulphate solution;
8% and 40% zinc chloride solution;
20% and 100% tannic acid solution;
45% negatol solution.
These drugs diffuse in blood circulation through crevicular epithelium, which is non-keratinized and semi-permeable, and cause vasoconstriction, which results in transient gingival shrinkage. This can cause transient ischaemia and helps to control seepage of blood or gingival fluid.36
Recent advances
Merocel: Merocel retraction strips are made of a synthetic material that is specifically chemically extracted from a biocompatible polymer (hydroxylate polyvinyl acetate) that creates a net-like strip (2 mm thick). This material is chemically pure, easily shaped, effective for absorption of intra-oral fluids, soft and adaptable and free of fragments.37
Expasyl: This is a paste for gingival retraction that not only opens the sulcus but also leaves the field dry, ready for impression-taking or cementation. It is mainly composed of micronized kaolin, aluminum chloride and water. The material is simple, rapid, safe, painless, haemostatic, economical and reliable.2
Impression techniques
The impression technique can have a negative impact on the soft tissues around the abutments, even causing irreversible damage if the technique is not properly carried out. Severe and painful periodontal reactions will occur if rubber-based impression material is introduced into the gingival tissues during impression-taking procedures.11 Careful visual inspection of the impression for torn areas is needed and, if evidence of tearing is detected, the clinician should immediately check the tissue to remove any remnant of the impression. Otherwise a foreign body of impression material can cause severe gingival inflammation and may be misdiagnosed at a subsequent appointment.2
Provisional restorations
Provisional restorations must provide an environment conducive for the maintenance of periodontal health.38 Provisional restorations that are poorly adapted at the margins are overcontoured or undercontoured and have rough or porous surfaces that can cause inflammation, overgrowth or recession of gingival tissues. The outcome can be unpredictable and lead to unfavourable changes in the tissue architecture that can compromise the success of the final restoration (Figure 6).
Crown contours are normally determined by tooth anatomy, periodontal condition, margin placement, and access for oral hygiene. Conflicting results have been given by different authors regarding contour of crowns. Yuodelis et al39 demonstrated that the greater the amount of facial and lingual bulge of an artificial crown, the more the plaque was retained at the cervical margin. Proper restorative contours require adequate tooth reduction to allow proper thickness of restorative materials, while allowing easy access for personal oral hygiene. The emergence profile of a restoration in aesthetic areas has two aspects: subgingival form and supragingival form. The subgingival form should follow the contours of the cement-enamel junction and support the gingival tissues. Within limits, increased thickness of interproximal subgingival contours leads to increased papillary height, while increased facial contours lead to apical positioning of the gingival tissues.8
When the gingiva contacts a flat tooth surface, there is a tendency to develop a thick free gingival margin. Overcontouring of restorations or faulty placement of contour is a much greater hazard to periodontal health than is lack of contour, since both supra-and subgingival plaque accumulation may be enhanced by overcontoured margins. The greater the convexity, the more difficult it is to remove the plaque.39 The facial or lingual surface of a restoration should not have more than 0.5 mm bulge adjacent to the gingival margin because this may interfere with adequate plaque removal.9
Interproximal contacts and embrasure space
Hirschfeld40 stated that improperly constructed restorations are one of the factors leading to food impaction. Open proximal contacts are considered to be contributing factors to periodontal pocket formation. Whereas deficient interproximal integrity may be unclear, open contacts leading to food impaction are often uncomfortable to the patient, and prevent the self-cleaning mechanisms of the adjacent cheek, lips and tongue, and it is still generally accepted that tight interproximal contacts are important for gingival health1 (Figure 7). Normally, there must be a positive contact relation, mesially and distally, of one tooth with another in each dental arch. The areas of contact are small and are surfaces, not mere points of contact. Contact areas keep food from being trapped between the teeth and help to stabilize the dental arches by the combined anchorage of all teeth in either arch in positive contact with each other. In order to maintain the healthy gingiva in the interdental areas, the contact points should be located incisally or occlusally and buccally.41 Proper contact and alignment of adjoining teeth will allow proper spacing between them for the normal bulk of gingival tissue attached to the bone and teeth.2 A significant relationship was seen between food impaction and contact type (greater food impaction at sites with open or loose contacts), and between food impaction and probing depth and loss of clinical attachment.1
Figure 7.
(a) Clinical and (b) radiographic image showing undercontoured restoration in relation to UL6, with no interproximal contact surface made between UL6 and UL7.
Cementation and polishing of restorations
After cementation of the restorations, all retained excess cement must be removed. When restorations extend below the gingival margin, particles of cement within the sulcus may be overlooked and can cause damage to the periodontal tissues.42 Although surface textures of restorative materials differ in their capacity to retain plaque, all can be adequately cleaned and maintained if they are polished.43,44
Summary
A healthy coexistence between dental restorations and their surrounding structures should be the goal of the conscientious dentist and the expectation of the informed patient. The successful integration of periodontal and restorative dentistry for both natural teeth and implants requires knowledge and application of both mechanical and biological principles as discussed in this first article. The second part describes the surgical techniques available for the maintenance of periodontal health.
