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Restorative interrelationships(carranza 2012)

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    Restorative interrelationships(carranza 2012) Restorative interrelationships(carranza 2012) Presentation Transcript

    • Meysam.aryam
    •  Biologic considerations  Esthetic tissue management
    • Biologic considerations  The supragingival margin has the least impact on the periodontium  The use of equigingival margins traditionally was not desirable (though to be more plaque retentive and esthetic prblemes after slightly recession)  From a periodontal view of point ,both supra and equigingival margins are well tolerated
    • Biologic width
    • Ramifications of a biologic width violation  On the mesial surface of the left central incisor, bone has not been lost, but gingival inflammation occurs.(more common)  On the distal surface of the left central incisor, bone loss has occurred, and a normal biologic width has been reestablished(one possibility)
    • Recession factors  Bone width (thin or thick?)  Gingiva (thin or fibrotic,flat or scalloped form?)
    • Biologic Width Evaluation  radiographs are not diagnostic because of tooth superimposition  A new radiographic technique called parallel profile radiographic technique (PPR) is used to measure the dimensions of the dental gingival unit (DGU). This technique could measure both the length and the thickness of the DGU with accuracy, as it is simple, concise, non-invasive, and a reproducible method.[2]
    • Biologic Width Evaluation  If a patient experiences tissue discomfort when the restoration margin levels are being assessed with a periodontal probe, it is a good indication that the margin extends into the attachment.
    • The signs of biological width violation are:  Chronic progressive gingival inflammation around the       restoration Bop localized gingival hyperplasia with minimal bone loss, gingival recession pocket formation clinical attachment loss Gingival hyperplasia is most frequently found in altered passive eruption and subgingivally placed restoration margins. [1]
    • Overhang  Jeffcoat and Howell (1980) demonstrated a link to the severity of the overhang and the amount of periodontal destruction  Overhangs were designated as large if they occupied >51% of the interproximal space.  Small and medium overhangs (o20% and 20–50% of the interproximal space,respectively) were not associated with bone loss[4]
    • overhang  Lang et al. (1983) investigated the specific aspects of the local bacterial accumulation associated with overhanging restorations.  The placement of subgingival overhangs resulted in changes in the associated microflora to that of one resembling the flora observed in adult chronic periodontitis.  Increased proportions of Gram-negative anaerobic rods, in particular black pigmented Bacteroides, were observed[4]
    • overhang  Thus, overhangs not only increase plaque mass but also increase the specific periodontal pathogens in the plaque.  Most overhanging restorations can be recontoured without replacing the restoration, and this should be considered a standard component of nonsurgical treatment.[4]
    • Alveolar bone changes under overhanging restorations  One study investigate changes in the trabecular architecture of the alveolar bone beneath overhanging restorations with bitewing radiographs in patients having no radiographically visible vertical bone loss  It did not show statistically significant differences between alveolar bone with and without overhanging restorations.[3]
    • Variations in biologic width  Average is 2mm  But biologic width violations can occur in some patients in whom the margins are located more than 2 mm above the alveolar bone leve  it varies from 0.75 to 4.3 mm in different individuals
    • specific biologic width assessment  To determine if the patient needs additional biologic width, in excess of 2 mm  It can be identified for the individual patient by probing to the bone level (referred to as “sounding to bone”) and subtracting the sulcus depth from the resulting measurement.
    • Kois [2] in 2000, proposed three categories of biological width based on the total dimension of attachment and the sulcus depth following bone sounding measurements. Normal crest patient In the normal crest patients, the mid-facial measurement is 3 mm and the proximal measurement ranges from 3 mm to 4.5 mm. Normal crest occurs approximately 85% of time. In these cases gingiva tends to be stable for a long term. High crest patient This is an unusual finding in nature and occurs approximately 2% of the time. There is one area where high crest is seen more often, in a proximal surface adjacent to an edentulous site. In the high crest patient, the mid-facial measurement is less than 3 mm. Low crest patient In the low crest patient group, the mid-facial measurement is greater than 3 mm and the proximal measurement is greater than 4.5 mm. Low crest occurs approximately 13% of the time. Traditionally a low crest patient has been described as more susceptible to recession secondary to the placement of an intracrevicular crown margin. [7]
    • Correcting Biologic Width Violations  Surgery  Orthodontics
    • surgery  In these situations the bone should be moved away from the margin by the measured distance of the ideal biologic width for that patient, with an additional 0.5 mm of bone removed as a safety zone.  Disadvantages(gingival recession , black triangles )
    • orthodontics  If the biologic width violation is on the interproximal side or if the violation is across the facial surface and the gingival tissue level is correct, orthodontic extrusion is indicated
    • Orthodontic extrusion  low orthodontic extrusion force and bringing the alveolar bone and gingival tissue with it  rapid orthodontic extrusion where the tooth is erupted to the desired amount over several weeks
    • Margin Placement Guidelines  the patient's existing sulcular depth be used as a guideline in assessing the biologic width requirement  With shallow probing depths, future recession is unlikely  Deeper sulcular probing depths provide more freedom in locating restoration margins  the deeper the gingival sulcus, the greater is the risk of gingival recession
    • Margin Placement Guidelines  Rule 1: If the sulcus probes 1.5 mm or less, place the restoration margin 0.5 mm below the gingival tissue crest  Rule 2: If the sulcus probes more than 1.5 mm, place the margin half the depth of the sulcus below the tissue crest  Rule 3: If a sulcus greater than 2 mm is found, especially on the facial aspect of the tooth, evaluate to see if a gingivectomy could be performed to lengthen the teeth and create a 1.5-mm sulcus. Then the patient can be treated using Rule 1.
    • Clinical Procedures in Margin Placement  The placement of supragingival or equigingival margins is simple because it requires no tissue manipulation.  But the subgingival margin placement is rather difficult.  So,prior the placement of margin subgingivally the preparation should be extended to the free gingival margin facially and interproximally.  The steps are as follows:
    • Tissue retraction  for protection from abrasion  For proper access by gingival retraction cords
    • For rule one margin  1 st cord is placed 0.5mm below the prepared margin.  This process: Protects the tissues Creates the correct axial reduction Establishes a desired subgingival level margin.  To create space and allow access for a final impression, it is now necessary to pack a second retraction cord  2 st cord is displaced the first cord apically and sits bw the margin &tissue
    • For rule two margin  two larger-diameter cords are used to deflect the tissue before extending the margin apically  a third cord is placed in preparation for the impression  electrosurgery is often required to remove overhanging tissue
    • Electrosurgery tip being held parallel to the preparation and resting on the previously placed retraction cord. This removes a minimal amount of tissue
    • The tissue should be only be removed from the inner surface of the sulcus
    • Provisional Restorations  Three critical areas must be appropriate to maintain the health and position of the gingival tissues: marginal fit crown contour surface finish of the interim restorations
    •  poorly adapted margins, overcontoured or undercontoured, and rough or porous surfaces can cause: inflammation, overgrowth or recession of gingival tissues
    • Marginal fit  Margins that are significantly open (several tenths of a millimeter) are capable of harboring large numbers of  bacteria and may be responsible for the inflammatory response seen.  However, the quality of marginal finish and the margin location relative to the attachment are much more critical to the periodontium than the difference between a 20-μm fit and a 100-μm fit
    • Crown Contour  There is a relationship between overcontouring and gingival inflammation, whereas undercontouring produces no adverse periodontal effect  In areas of the mouth in which esthetic considerations are not critical, a flatter contour is  always acceptable.
    • Subgingival Debris  Leaving debris below the tissue during restorative procedures can create an adverse periodontal response.  The cause can be retraction cord, impression material, provisional material, or either temporary or permanent cement
    • Stain medication  The aim of this study was to investigate the association between statin medication and periodontal infection in an adult population.2009[5]  RESULTS: they found a weak negative association between statin medication and periodontal infection among subjects with dental plaque or gingival bleeding. Among subjects with no gingival bleeding, statin medication was found to be associated with an increased likelihood of having deepened periodontal pockets.  CONCLUSION: Statin medication appears to have an effect on the periodontium that is dependent on the inflammatory condition of the periodontium. More evidence is needed to achieve a comprehensive understanding of the effects of statins
    • Hypersensitivity to Dental Materials  Inflammatory gingival responses have been reported related to the use of nonprecious alloys in dental restorations.  Typically, alloys containing nickel.  responses to precious alloys are extremely rare  tissues respond more to the differences in surface roughness of the material rather than to the composition of the material. (The rougher the surface , the greater are the plaque accumulation and gingival inflammation)  porcelain, highly polished gold, and highly polished resin all show similar plaque accumulation.
    • Esthetic tissue management
    • Managing Interproximal Embrasures  the free gingival margin averages 3 mm above the bone  the tip of the papilla averages 4.5 to 5.0 mm above the interproximal bone (but has the same biologic width)  Then the interproximal area will have a sulcus 1.0 to 1.5 mm deeper than that found on the facial surface.
    • Relationship between gingival embrasure volume and papillary form  A, gingival embrasure of the teeth is excessively large the result of a tapered tooth form. the shape of a normal papilla but rather has a blunted form and a shallower sulcus.  B,Because of the more closed embrasure form from the teeth in the papilla completely fills the embrasure and has a deeper sulcus, averaging 2.5 to 3.0 mm.  Note that the ideal contact position is 3 mm coronal to the attachment
    • two causes of open gingival embrasures:  (1) because of bone loss  (2) the interproximal contact is located too high coronally, there are two potential reasons: a) If the root angulation of the teeth diverges, the interproximal contact is moved coronally . b) If the roots are parallel problem is probably related to tooth shape, specifically an excessively tapered form.  Restorative dentistry can correct this problem by moving the contact point to the tip of the papilla
    • Methods of altering gingival embrasure form  A, Typical open gingival embrasure caused by excessively tapered tooth form.  B, Common method employed by restorative dentists to correct the embrasure, in which material is added supragingivally.(overhangs)  C, Correct method of closing the gingival embrasure, in which the margins of the restoration are carried 1.0 to 1.5 mm below the tip of the papilla.
    • This patient has parallel roots, has recently completed orthodontic therapy, and is unhappy with the open gingival embrasure between her central incisors. An evaluation of papillary height reveals that all are at an equal level. This can only mean that the open embrasure is the result of an overly tapered tooth form
    • A metal matrix band has been shaped to the desired tooth form and placed 1.0 to 1.5 mm below the tip of the papilla.
    • One-year recall photograph
    • Managing Gingival Embrasure Form for Patients with Gingival Recession  In esthetic area it is necessary to carry the interproximal contacts apically toward the papilla(restorations, tissuecolored ceramics )  In the posterior areas it is often impossible to carry the proximal contacts to contact the tissue without creating large overhangs on the restorations.the contact should be moved far enough apically.
    • Pontic Design  Sanitary  ovate  ridge-lap  modified ridgelap
    • sanitary pontic  Although the sanitary pontic design provides the easiest access for hygiene procedures, it is rarely used because of its unesthetic form and a variable acceptance of the open contour by patients
    • ovate pontics  it is the ideal pontic form. It is created by forming a receptor site in the edentulous ridge with a diamond bur or by electrosurgery.  the depth of the receptor site depends on the esthetic requirements of the pontic.  In highly esthetic areas such as the maxillary anterior region, it is necessary to create a receptor area that is 1.0 to 1.5 mm below the tissue on the facial aspect.  This site can then be tapered to the height of the palatal tissue to facilitate hygiene access from the palatal side
    • Ovate pontics  The receptor site has been created 1.0 to 1.5 mm apical to the free gingival margin on the facial aspect.  On the palatal side, the pontic is tapered so that the receptor site is not extended below tissue; this allows easier access for oral hygiene.  Note that when the receptor site is created, the bone must be a minimum of 2 mm from the most apical portion of the pontic.
    • Ovate pontics in less esthetic areas  it is possible to create a flattened receptor site in which the pontic sits flush with the ridge. This facilitates oral hygiene.
    • Ridge augmentation  It is important to realize that certain soft tissue ridge     parameters must exist. First, the ridge height needs to match the ideal height of the interproximal papillae . Second, the gingival margin height must also be at the ideal level, or the pontic will appear too long. Third, the ridge tissue must be facial to the ideal cervical facial form of the pontic so that the pontic can emerge from the tissue.(create illusion) If any of these three areas is inadequate,ridge augmentation is needed.
    • Ridge augmentation  RA procedures should be completed before, or in conjunction with, fabricating an ovate pontic.  When constructing the final restorations, the contours of the developed ovate pontic receptor site can be conveyed to the laboratory by capturing a soft tissue impression 4 to 6 weeks after the site has been created
    • Ovate pontics after extraction  When a tooth is removed,The gingiva recedes 1.5 to 2.0 mm  it can be prevented, By inserting the correct pontic form 2.5 mm into the extraction site the day the tooth is removed.  At 4 weeks, the 2.5-mm extension can be reduced to a 1.0- to 1.5-mm extension to facilitate hygiene.
    • Patient who will have the right central incisor extracted because of periodontal disease.
    • Because the patient desired to alter the esthetics of her remaining anterior teeth, all the anterior teeth were prepared before removal of the right central incisor
    • The key to maintenance of the interproximal papilla is that the ovate pontic extend 2.5 mm into the extraction site on the day of extraction.
    • Note that when the provisional restoration is seated on the day of the extraction, 2.5 mm of the pontic extends upward into the extraction socket.
    • Nine months after placement of the provisional restoration. (At 4 weeks after placement, the pontic was shortened to extend 1.5 mm into the extraction site to facilitate oral hygiene.)
    • Ovate pontic site after removal of the provisional restoration and before final impressions.
    • Two-year recall photograph of the final fixed prosthesis
    • full ridge-lap pontic  it is an outdated design that straddles the convexity of the ridge buccolingually and creates an undersurface that is entirely concave and cannot be cleaned.  It is not recommended for use in any situation
    • modified ridge-lap pontic  it can be an acceptable design if inadequate ridge exists to create an ovate pontic.  the pontic follows the convexity of the ridge on the facial aspect but stops on the lingual crest of the ridge  the more open lingual form allows adequate access for oral hygiene
    •  1.Gargiulo AW, Wentz FM, Orban B. Mitotic activity of human oral epithelium exposed to 30 per cent hydrogen peroxide. Oral Surg Oral Med Oral Pathol 1961;14:474-92.  2. Kois JC. The restorative-periodontal interface: Biological parameters. Periodontol 2000 1996;11:29-38  3.Clin Oral Investig. 2010 Oct;14(5):543-9. doi: 10.1007/s00784009-0334-9. Epub 2009 Aug 18. Alveolar bone changes under overhanging restorations. Yasar F, Yesilova E, Akgünlü F.  4.Padbury Jr A, Eber R, Wang H-L. Interactions between the gingiva and the margin of restorations. J Clin Periodontol 2003; 30: 379–385. r Blackwell Munksgaard, 2003.  5. Saxlin T, Suominen-Taipale L, Knuuttila M, Alha P, Ylöstalo P  Institute of Dentistry, University of Oulu, Oulu, Finland. tuomas.saxlin@oulu.fi  Journal of Clinical Periodontology [2009, 36(12):997-1003]