Sometimes Implant Is Not the Answer!! – A case report of crown lengthening procedure in the maxillary anterior region.
Author: Dr. Sonali Luthra Gandhi
Co-Authors: Dr. Komal Khatri Majumdar
Dr. Indranil Majumdar
Crown lengthening has been traditionally utilized as an adjunct to restorative dentistry, typically in situations where subgingival caries or fractures require the exposure of sound tooth structure and reestablishment of the biologic width space. With the increasing popularity of aesthetic-oriented treatment, an understanding of the therapeutic synergies brought about by an interdisciplinary approach has developed. As a result, crown lengthening procedures have become an integral component of the aesthetic armamentarium and are utilized with increasing frequency to enhance the appearance of restorations placed within the aesthetic zone. This article discusses a case report in which the natural teeth were restored by doing a crown lengthening procedure in the maxillary anterior region there by attaining enough ferrule for retention as well as achieving esthetic gingival contours.
Crown-lengthening surgery has been categorized as esthetic or functional. The term “functional” relates to exposure of subgingival caries, exposure of a fracture or both. Often, the discussion of crown lengthening in the anterior sextants is presented in the context of “esthetic” surgery. Indeed, functional and esthetic therapy can converge in the esthetic zone when subgingival caries does not extend greatly or at all to the root.Without functional crown lengthening, the restorative margins may extend deep into the periodontal tissues and possibly invade the biologic width. This then would cause a resorptive response by the body, leading to uncontrollable loss of alveolar bone, probably to a greater degree than anticipated.
Following criteria must be taken into consideration for the procedure:-
- Biological width
- Gingival Zenith (anterior region)
- Biological Width:-
Biological 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. This term was based on the work of Gargiulo et al (1961), who described the dimensions and relationship of the dentogingival junction in humans. They reported the average length of the dentogingival junction to be 2.04 mm (Fig-1). They identified the subcomponents of the dentogingival junction as the connective-tissue attachment (mean value:1.07 mm) and the epithelial attachment (mean value: 0.97 mm).There is general agreement that placing restorative margins within the biologic width frequently leads to inflammation, clinical attachment loss, and bone loss.In contemporary practice, it generally is accepted that a 3-mm distance would significantly reduce the risk of periodontal attachment loss induced by subgingival restorative margins.
Fig-1: Biological width
The Journal of Prosthetic Dentistry’s 2005 Glossary of Prosthodontic Terms defines a ferrule as a “metal band or ring used to fit the root or crown of a tooth.11 Sorensen and Engelman12 redefined the ferrule effect as “a 360-degree metal collar of the crown surrounding the parallel walls of the dentine extending coronal to the shoulder of the preparation.”
The dentist should retain as much coronal tooth structure as possible when preparing pulpless teeth for complete crowns to maximize the ferrule effect. A minimal height of 1.5 mm to 2 mm (Fig-2) of intact tooth structure above the crown margin for 360 degrees around the circumference of the tooth preparation appears to be a rational guideline for this ferrule effect. Surgical crown lengthening or orthodontic extrusion should be considered with severely damaged teeth to expose additional tooth structure to establish a ferrule.
- Gingival Zenith level:-
In the esthetic region especially in the maxillary anterior region it is not only important for us to provide a restoration that is functionally stable but also it should be esthetic and should give the patient a beautiful smile. One significant feature of gingival morphology is the gingival line, which is defined as the line joining the tangents of the gingival zeniths of the central incisor and canine (Fig.-3.1). The gingival zenith of the lateral incisor is 1-2mm below the gingival line. The gingival zenith is the most apical aspect of free gingival margin. The gingival zenith is located distal to the long axis of the central incisor and canine whereas it is located along the long axis in the mandibular incisor and maxillary lateral incisor (Fig.-3.2).
Fig-3.1: Gingival Zenith Line
(GZ – Gingival Zenith)
(ZL – Zenith Line)
(CW – Crown Width)
(LA – Long Axis)
(LI-GZ – Lateral Incisor Gingival Zenith)
Fig-3.2: Gingival Zenith in Relation to the Long Axis of the tooth.
This case was done in the author’s private practise. All clinical procedures were fully explained to the patient, who signed an informed consent form authorizing treatment and publication of the case.
The patient, A 43 years old female, in good health conditions without any history of any chronic disease came to the private practice with a chief complaint of decementation of old prosthesis.
Clinical Examination revealed fractured restorations with relation to 11, 21 and 22. Further examination showed the presence of cast posts in all three teeth with no ferrule and residual caries around them with uneven gingival margins.
Fig-4.2: Decementation of old Prosthesis; Uneven Gingival Margins.
Radiographic examination (Intraoral Periapical) revealed well done root canal treatment in relation to 11, 21, and 22 with no periapical radiolucency with intact lamina dura and no periodontal ligament space widening.
The first line of treatment was to remove all the residual caries and restore the teeth using composite (3M Filtek Z350) using the old cast posts since there was no damage done to them.
The next line of treatment was the crown lengthening procedure. The crown lengthening procedure was to be done for added ferrule for the retention of new prosthesis and to match the gingival levels of the adjacent teeth. The gingival zenith levels were checked and bone sounding was done to check the biological width. Markings were done to design the flap. Internal Bevel and Sulcular incisions were given with a 15 No. Surgical Blade and the gingival tissue was removed. An apical repositioned flap with minimal exposure was done for the osseous recontouring. This was done with a round bur and continuous saline irrigation to achieve biological width and to maintain harmony between the periodontal and dental tissues. Once this was done closure was achieved with horizontal mattress sutures (silk, fine thread).
The crown lengthening procedure revealed new defects which were then restored using composite (3M Filtek Z350) and new finish lines were made. Immediately the teeth were provisionalised with acrylic crowns.
The patient was recalled after 7 days and the sutures were removed. After 7 weeks the provisionals were removed and impressions were made and sent to the laboratory for the fabrication of the final prosthesis.
Finally after 8 weeks the teeth were restored with individual E-max crowns.
Fig-5.1: Probing depth and bone sounding.
Fig-5.2: Checking for Gingival Zenith Levels
Fig-5.3: Flap Design.
Fig-5.4: Internal Bevel Incision
Fig-5.6: Tissue Removal.
Fig-5.7: Apical Repositioned Flap with Minimal Exposure; Osseous Recontouring with continuous Saline irrigation.
Fig-5.8: Result after Crown Lengthening Procedure.
Fig-5.9: Defects Restored and New Finish Lines Prepared.
Fig-5.10: Immediate Provisionalisation.
Fig-5.11: Healing after 7 days; Harmonious Smile.
Fig-5.12: Healthy Periodontium.
Fig-5.13: Final Prosthesis.
In contemporary dentistry, dentists are confronted on a daily basis with clinical decision making regarding dentition affected with significant caries or subgingival fractures. The dentist weighs the clinical findings and patients’ concerns in the balance to determine if the tooth should be extracted or restored. We are, of course, in an age of dental implants, an era in which heroic efforts to salvage extensively damaged teeth are fading. This, however, does not mean that dentists should abandon tools commonly used to preserve the natural dentition, tools such as complex restorative treatment, possible concomitant endodontic therapy and periodontal therapy. Moreover, if the patient wishes to retain part or all of his or her own dentition, providing the outcome of these treatment options are predictable, the dentist should consider honoring those wishes.
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