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Amount of tooth substance gained by crown lengthening:a systematic reviewPresented by: Dr. Syeda Mahvash HussainResident Operative Dentistry Aga Khan University Hospital Karachi Contributors: Drs. Maham Muneeb Lone, Sana Ehsen Supervised by: Dr. Farhan Raza Khan & Dr. Munawar Rahman

Biologic Width TOOTH

GINGIVA

Takei, HH; Azzi, RR; Han, TJ: Preparation of the Periodontium for Restorative Dentistry. In Newman, MG; Takei, HH; Carranza, FA; editors:Carranzas Clinical Periodontology, 9th Edition. Philadelphia: W.B. Saunders Company, 2002. page 945.

2The 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.It is the distance established by "thejunctional epitheliumandconnective tissue attachment

The biologic width is patient specific and may vary anywhere from 0.75-4.3mmbut the mean value is 2mm2

Chronic inflammation and bleeding Loss of alveolar bone because of restoration overhang 3If a dental restoration violates the biologic width:chronicpain andinflammationof the gingivaAnd unpredictable loss ofalveolar bone

This distance is important to consider when fabricatingdental restorations, because they must respect the natural architecture of the gingival attachment if harmful consequences are to be avoided. 3

Crown Lengthening4Crown lengthening is the surgical procedure performed to expose tooth structure by removing gingival tissue, bone or both to gain adequate height for the purpose of providing a prosthesisAs we can see in this diagram this is the old gum line b4 CLS and this is the new gum line after CLSAnd it can be appreciated that there is a significant ATSG after CLS

Why would you need it? 4Indications5There are certain clinical situations where proper treatment would not be possible without crown lengthening surgery5Methods Gingivectomy/ gingivoplastySurgical bladeElectro cauteryLasers

6There are several methods by which CLS can be doneGingivectomy involves removing the gingival tissue to gain crown height with out raising a flap6Apical repositioning of flapWith osseous reductionWithout osseous reductionOrthodontic extrusion Combination

7Apical repositioning involves raising a flap to proceed with CLSIt could either be with bone reduction or without bone reduction7ReviewThe most common technique for crown-lengthening surgery is APF with osseous surgery

Padbury Jr A, Eber R, Wang H-L. Interactions between the gingiva and the margin of restorations. J Clin Periodontol 2003; 30: 379385

8According to a review by padbury et al

8Review QuestionAmount of tooth substance gained by crown lengthening

9With these facts at hand and in mind we still wanted to know which technique provides the best results in terms of amount of tooth substance gained

This is the reason we decided to conduct a systematic review which lead us to formulate our review question.

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PICOPatient /population :Human, mature permanent teethIntervention:Different methods of crown lengthening Comparison of the intervention: Comparing the different methodsOutcome(s) :Amount of tooth structure gained 10Our PICO model was Patient /population : Human, mature permanent teeth which required CLS prior to a dental restorationIntervention: Different methods of crown lengtheningComparison of the intervention: Comparing the different methods of CLSOutcome : Amount of tooth structure gained

10Registration of Review

Registration No: CRD4201401326611PROSPERO is an international database of prospectively registered systematic reviews in health sciences

Registration with Prospero is imp b/c it increases transparency, helps safeguard against bias and avoids unplanned duplicationThe registration of a SR with Prospero is some what similar to registration of a meta analysis with the Cochrane collaboration which maintains a log of meta analysis11Search StrategyGoogle scholarPubMed(NLM)CINAHL Plus (Ebsco)

Gingivectomy or Gingival cautery or Gingivoplasty or Gum resection ANDTooth gain or Tooth exposure or Crown lengthening or Ferrule12Literature search key termswas conducted in 3 major Health Sciences Databases from 1978 till dateAnd the key terms we used to conduct this search were

12Study SelectionInclusion Criteria:

Exclusion Criteria:

13Studies-Human permanent mature teeth where CLS was doneOutcome-Amount of tooth gainedPrimary teethImmature permanent teeth Animal basedIn vitro studiesLanguages other than EnglishStudies Which had assessed the amount of tooth structure gained through CLS in human permanent mature teeth

Clinical trials which assessed the amount of tooth gained as an outcome

13First Electronic Search 412 Selection of relevant titles 273After excluding No Abstract available83Abstracts available 190Techniques only different outcome 33Case reports 92 RCT/Clinical trials n=8(321 teeth)Reviews/guidelines42 Trials not relevant to objective10Finally selected for this review14DuplicatesNot relevant to topicNot in EnglishAnimal based studiesCommentary 1C.S survey 1In-vitro 1Retrospective 2 In collaboration with the librarian we had 412 articles as the initial electronic search14

Registration No: CRD4201401326615DATA EXTRACTIONThis was the customized form which we used to extract data from the included studies for assessment of study quality and evidence synthesis

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16DATA EXTRACTIONThe compiled data was analyzed using SPSS version 19.0

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17In the initial part of the review the unit of analysis was the individual studyHowever, after selecting the final pool of studies the unit of analysis shifted to the individual teeth undergoing the CLS

1718So when we tabulated our results we found that the total number of teeth assessed in all 8 studies was 321with a minimum of 20 teeth assessed by N. Ayubian and a maximum of 84 teeth assessed by Ponteriero18Contribution of Data By Weight19N.AYUBIAN n=20HERRERO n= 21HAN n= 27DINIZ n= 30DEAS n= 43BRAGGER n= 43ARORA n= 53PONTERIERO n= 84The contribution of individual study to the overall pool of 321 teeth is as follows1920The surgical site was mentioned in 2/8 studies which made a total of 73 from the 321 teeth assessed2021And the radiographic evaluation was assessed in only 1/8 studies which had 30 teeth2122In 7 out of the 8 studies which is a total of 291 teeth did not mention which jaw maxillary or mandibular they belonged to 222380 of the 321 teeth assessed in the 8 studies were affected because of subgingival cariesAnd another 53 had a fracture going sub-gingivally and the remaining 5/8 studies did not mention the clinical presentation 23Indication For Crown Lengthening24the most common indication for crown lengthening was. for proper restorative Tx 24Follow up of CLSNumber of teeth Minimum(mm) Maximum(mm) Mean (mm)Std. DeviationAmount of tooth structure gained Initially with APF and bone reduction 3001.324.002.461.03Amount of tooth structure gained in 3 months with APF and bone reduction 1461.601.871.750.13Amount of tooth structure gained in 6 months with APF and bone reduction 1961.001.801.490.32Tooth Structure Gained By Crown Lengthening25When we ran the descriptive statistics for the amount of tooth structure gained 7/8 studies (300teeth) reported the initial gain in tooth structure after CLS with a mean of 2.46mmWhile 4/8 studies (146teeth) reported the amount gained after 3months of CLS and the mean was 1.75mm

However only 5/8 studies (196teeth) followed their cases till 6 months after CLS and they reported the mean amount gained to be 1.49mm25

DISCUSSION26AUTHOR TITLE SEARCH STRATEGYSUMMARYHempton T.J et al 2010Contemporary crown lengthening therapy

A REVIEW

Pub med

Google scholarMethods of CLS

Sharma A et al2012Short clinical crowns (SCC) treatment considerations and techniques A REVIEWPub med Methods for CLSThe role of restoration margin locationEffects of violation of the supracrestal gingivae AKUH 2014Amount of tooth substance gained with crown lengthening

A SYSTEMATIC REVIEWPub med Google scholarCINAHL plus (Ebsco) Identified the characteristics of the relevant studies:

Most commonly used method for CLSType of studyAmount of tooth substance gained Year of Publication

27When comparing our study with other researchersWe found that both hempton et al and sharma et al published a review using search engines like PubMed and google scholarWhile we used PubMed and CINAHL plus in our search strategy and our study is a SRIn summary we looked at Most commonly used method for CLSType of studyAmount of tooth substance gained Year of Publication

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conclusions28The number of clinical trials on CLS were limited n = 8 ( 321 teeth)

The quality of the studies which report data on CL was mostly inadequate

APF with bone reduction was the most commonly used technique (7/8 studies) for CLS

The mean amount of tooth structure gained initially was 2.46mm which decreased to 1.49mm after 6months

29The number of clinical trials on CLS were limited n = 8 ( 321 teeth)

The quality of the studies which report data on CL was mostly inadequate b/c basic demographics like the surgical site, the type of jaw (mand or max) radiographic evaluation and clinical presentation were missing from most of the studies evaluated29

Strengths and Limitations30STRENGTHS The first ever Systematic review on this topic

LIMITATIONS Only three search engines were used

Studies lacked homogeneity in reporting the outcome

Only experimental studies were included

31Its an ongoing research and we intend to explore data from other search engines such as the Cochrane library and Google scholar to make sure that we dont miss any information before publishing

Review question too focusedOur review question was too specific therefore we could not include studies which measured variables like biologic width and gingival recession 31Explore more data through other search engines to expand existing research

More clinical trials are needed to answer the research question

32recommendationsExplore more data through other search engines to expand existing research

More clinical trials are needed to answer the research question

32Thank you!

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