Crown lengthening


Published on

1 Comment
No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Crown lengthening

  1. 1. Dr.Khalid Aboalshamat B.D.S
  2. 2. Case <ul><li>40 years old female presented to the dental clinic complaining from inability to eat properly on her right side due to fractured crown. The patient gave a history of previous endodontic treatment. Upon intra oral examination the sound tooth structure was deep below the gum tissue and not accessible, very narrow zone of attached gingiva was also noticed. The procedure involves adjusting the levels if the gum tissue and bone around the tooth in question, to create a new gum to tooth relationship. This allow us to reach the edge of the restoration, ensuring a proper fit to the tooth. It should also provide enough tooth structure so the new restoration will not come loose in the future. This allows her to clean the edge of the restoration when she brushes and flosses to prevent decay and gum disease. </li></ul>
  3. 3. <ul><li>What are the biomechanical consideration that governs crown lengthening procedure? </li></ul><ul><ul><li>Biological width </li></ul></ul><ul><ul><li>Ferrule effect </li></ul></ul><ul><ul><li>Crown to root ratio </li></ul></ul><ul><ul><li>Tx planing </li></ul></ul>
  4. 4. Biological width <ul><li>Biologic width is the distance established by &quot;the junctional epithelium and connective tissue attachment to the root surface&quot; of a tooth. </li></ul><ul><li>Or it is the distance from the crest of the bone to the base of the pocket. </li></ul>
  5. 5. <ul><li>So we have to leave 3 mm the restoration and the alveolar crest. </li></ul><ul><li>When restorations do not take these considerations into account and violate biologic width, three things tend to occur: </li></ul><ul><ul><li>chronic pain </li></ul></ul><ul><ul><li>chronic inflammation of the gingiva </li></ul></ul><ul><ul><li>unpredictable loss of alveolar bone </li></ul></ul>
  6. 6. Ferrule effect <ul><li>A ferrule, in respect to teeth, is a band that encircles the external dimension of residual tooth structure. </li></ul><ul><li>another 2 mm should be removed to reveal enough tooth structure to allow for a 2 mm ferrule. </li></ul><ul><li>it has been shown it significantly reduce the incidence of fracture in the endodontically treated tooth. </li></ul><ul><li>Some recent studies suggest that, it should not be provided at the expense of the remaining tooth/root structure. </li></ul><ul><li>On the other hands some look for the longevity of the restoration and recommend that if we cannot do ferrule effect it is better to extract the tooth. </li></ul>
  7. 7. Crown-to-root ratio <ul><li>removing bone for a crown lengthening procedure will: </li></ul><ul><ul><li>damage the bony support of adjacent teeth </li></ul></ul><ul><ul><li>unfavorably increase the crown-to-root ratio. </li></ul></ul><ul><ul><li>it is almost impossible to regain it to previous levels and it will make problem when pt. wants to do an implant in the future. </li></ul></ul>
  8. 8. Treatment planning <ul><li>It is important to consider the many options available during the treatment planning stages of dental care. </li></ul><ul><li>When making crown lengthening it sometime need : endodontic Tx , post and core and crown. </li></ul><ul><li>Thus it may be better from economic and longevity side view to do implant in place. </li></ul><ul><li>You have to discuss all of these options with your pt. </li></ul>
  9. 9. <ul><li>How long dose it take before proceeding to the final restoration ( healing). </li></ul>
  10. 10. <ul><li>Not before 4 weeks, and not before 6 weeks in the esthetic area. </li></ul><ul><li>The pt. should: </li></ul><ul><ul><li>Be in good systemic condition </li></ul></ul><ul><ul><li>No infection </li></ul></ul><ul><ul><li>Margins are supragingval </li></ul></ul><ul><li>Why? </li></ul><ul><ul><li>The epithelial basal membrane – membrana basalis (lat.) bonding epithelium with connective tissue under it, totally recovers just after 4 weeks </li></ul></ul><ul><ul><li>there is possibility to retraction </li></ul></ul><ul><ul><li>The gingiva is weak and easy to be injured. </li></ul></ul>
  11. 11. <ul><li>What are the complications of crown lengthening? </li></ul>
  12. 12. <ul><li>Unaesthetic appearance : especially in the Ant.: </li></ul><ul><ul><li>Improper contour </li></ul></ul><ul><ul><li>Loss of papilla </li></ul></ul><ul><ul><li>Open interdental space </li></ul></ul><ul><ul><li>Longer crown than adjacent. </li></ul></ul><ul><li>Improper crown root ratio </li></ul><ul><li>Loss of PDL and bone of adjacent </li></ul><ul><li>No enough bone for implant in the future. </li></ul><ul><li>prolonged bleeding during crown lengthening </li></ul><ul><li>risk of developing an infection </li></ul><ul><li>sensitivity to hot and cold because the roots of the teeth are now exposed </li></ul>
  13. 13. <ul><li>What is the influence of surgical technique on gingival margin stability? </li></ul>
  14. 14. <ul><li>After six weeks : attachment level and probing depth did not change, the level of marginal gingiva established almost precisely corresponds to the level of marginal gingiva after healing. </li></ul><ul><li>Between 6 weeks and 6 monthsin 85 % of cases there were no or minimal -/+1 mm changes of marginal gingiva level. </li></ul><ul><li>In 12 % of cases gingival retractionoccurs more than 1 mm </li></ul>Br ن gger U, Launchenauer D, Lang NP. Surgical crown lengtheningof the clinical crown. J Clin Periodontol 1992; 19: 58-63.
  15. 15. <ul><li>Deas concluded that there was a significant tissue rebound after crown lengthening procedures that had not fully stabilized at 6 months. </li></ul><ul><li>Pontoriero reported that during a 1-year healing period after apically positioned flap surgery and osseous resection margin grow in coronal direction. </li></ul><ul><li>This growing increase with thick gingiva and vary according to healing variation in healing response. </li></ul><ul><li>Another study show decrease in the gingival margin by 0.5- 0.6 (2007) </li></ul>Pontoriero R, Carnevale G . Surgical crown lengthening : a 12-month clinical wound healing study . J Periodontol .
  16. 16. <ul><li>According to Deans: there is an inverse correlation between the distance of the flap to the osseous crest at the time of suturing, and the amount of tissue rebound: indicating that greater gingival rebound occurred when the flap margin was positioned closer to the bony crest. So we should avoid tightening the suture over the bone. </li></ul>
  17. 17. <ul><li>To increase the predictability of gingival margin stability: </li></ul><ul><ul><li>use of full-thickness flaps to preserve the entire dimension of the dentogingival complex. </li></ul></ul><ul><ul><li>followed by adequate osseous resection measured from a restorative landmark to ensure sufficient bone removal. </li></ul></ul><ul><ul><li>avoidance of periosteal sutures to apically position the flap. </li></ul></ul><ul><li>By using these guidelines it is possible to take final impression after 3 months even in esthetic zone. </li></ul>