Digital Versus Conventional Guided Gingivectomy

Fully Digital Guided Gingivectomy in Management of Gummy Smile: Evaluation of Accuracy and Patient Satisfaction

The goal of this randomized controlled clinical study is to compare Fully digital to conventional guided Gingivectomy procedure in management of excessive gingival display caused by altered passive eruption type 1A. The main question it aims to answer is: Does the fully digital guided gingivectomy approach able to introduce a more precise, accuracy and reliability technique with more patient satisfaction compared to the conventional guided method?

Nowadays, the concept of smile and dental esthetics is no longer limited to the teeth. The essentials of a smile involve the relationship between the three primary components: the teeth, lip framework, and the gingival scaffold. The term "pink aesthetics" refers to the aesthetics of gingival tissues, which play a significant influence in smile aesthetics. Excessive gingival display while smiling, also usually known as a "gummy smile," is a common esthetic concern among dental patients and, being largely viewed as unesthetic, leads many patients to seek some form of treatment to address the issue. Gummy smile (Excessive gingival display) is recognized by the American Academy of Periodontology (AAP) as a deformity and mucogingival condition that affects the area around the teeth. This condition could be caused by many etiological factors: short lip, hypermobile/hyperactive lip, short clinical crowns, dentoalveolar extrusion, altered passive eruption (APE), gingival hyperplasia, and vertical maxillary excess. Altered passive eruption defined as "the gingival margin in the adult is located incisal to the cervical convexity of the crown and removed from the cementoenamel junction of the tooth". Altered passive eruption classified into two main classes according to the relationship of the gingiva to the anatomic crown and furthermore subdivided those classes according to the position of the osseous crest. The two types are subdivided into four categories: 1A, 1B and 2A, 2B. The diagnosis of APE is made on a collective clinical and radiographic examination, it begins with analyzing the repose during a natural smile followed by analyzing the gingival display, the alveolar crest level, as well as the lip line of the patient. Determination can be made whether a gingivectomy alone will suffice or a gingival flap will be needed with or without ostectomy will depend of the diagnosis of APE and classification of each case. The selection of one technique over another depends on several patient related factors such as esthetics, clinical crown to root ratio, root proximity, root morphology, furcation location, individual tooth position, collective tooth position and ability to restore the teeth. The gingivectomy approach alone is used when 3 mm gingival tissue or greater exists from bone to gingival crest, and an adequate attached gingiva will remain after surgery (APE type IA). A diagnostic wax-up then an intraoral fabricated mock-up representing the desired outcome can assist in the selection of proper planning of the need for periodontal surgical approach. Diagnostic mock-up fabricated using a temporary bis-acrylic resin with a putty guide directly from the wax-up can be used to provide the patient and clinician with an evaluation of the future outcome and can be used as a surgical guide for gingivectomy procedures. The major limitations with conventional guided gingivectomy procedure would be the time consumed during making and modifying conventional wax-ups as well as the unpredictable estimate of where the gingival margin should be. Utilization of digital workflows allowed the enhancement of communication and might improve the predictability of contemporary gingivectomy approach. The introduction of computer-aided design and computer-aided manufacturing (CAD-CAM) techniques has helped surgeons perform more precise and predictable surgery and contributed to improved esthetics. By combining the use of Digital Smile Design and CAD/CAM technology with (3D) printing, a surgical guide for Gingivectomy procedure could be produced. The aim of the present study will be to evaluate accuracy and reliability of digital guided method of gingivectomy procedure using CAD CAM technology versus conventional method using resin Mock-up as gingivectomy surgical guide. Research Question "Does the fully digital guided gingivectomy approach able to introduce a more precise, accuracy and reliability technique with more patient satisfaction compared to the conventional guided method?"

gummy smile, excessive gingival display, Altered Passive Eruption, gingivectomy, fully digital guided

The current investigation will be a single-blinded clinical trial. Blinding included the assessor, and the statistician. Its impossible for the operator who performed the surgical procedure to be blinded as the interventions will be completely different and the patient also.

Full history with clinical and radiographic examination (CBCT) to aid in patient's selection. Supra- and sub-gingival debridement. Oral hygiene instructions (OHI) Presurgical intraoral scanning using an intraoral scanner (IOS) Fabrication of the Gingivectomy guide: Convert (DICOM) file to STL file then merged to STL file corresponding oral soft tissues 3D data obtained by IOS using software of surgical planning. Digital waxing up with new desired positions of gingival margins and zenith points performed. Designing Gingivectomy guide then exported to a 3D printer and mill a transparent resin gingivectomy guide. Surgical Procedure: anesthetized the patient using local anesthesia, Surgical incision using 15c blade following CEJ anatomy will be made at each tooth using the Gingivectomy guide as reference to new gingival level and being careful to preserve the gingival papillae without involving the palatal surfaces. Postoperative care

Full history with clinical and radiographic examination (CBCT) to aid in patient's selection. Supra- and sub-gingival debridement with OHI Gingivectomy guide fabrication: Impressions and casts obtained. Waxing-up included new positions of gingival margins and zenith points. Silicone index with condensation silicone impression materials made with pressure on the cast to reproduce the details of the wax, then filled after setting with resin material and placed in the patient's mouth. Resin mock-up trimmed with blade to define the correct new gingival level. After the patient accept the mock-up design will used as Gingivectomy guide. Surgical Procedure: anesthetized the patient using local anesthesia, Surgical incision using 15c blade following CEJ anatomy will be made at each tooth using the Gingivectomy guide as reference to new gingival level and being careful to preserve the gingival papillae without involving the palatal surfaces. Postoperative care

Intraoral digital scanning for obtaining gingival contour will be made immediately postsurgical, 4 weeks and 2 months after surgery and exported in STL files format. Diagnostic waxing-up on poured cast (for group 2) will be digitalized with a model scanner and exported in STL file format. Accuracy will be evaluated by: Superimposing postoperative intraoral digital scanning STL files with virtually designed diagnostic waxing STL file (for group 1) and obtain matching differences in height of gingival margin in relation to Muco-gingival junction. Superimposing postoperative intraoral digital scanning STL files with digitized waxing-up STL file (for group 2) and obtain matching differences in height of gingival margin in relation to Muco-gingival junction.

A 5-item custom made questionnaire will give to the patients to be answered for assessing their satisfaction with the whole procedure and the results of the procedure performed. Post-operative pain (POP): It will be evaluated indirectly based on the mean consumption (in mg) of analgesics (ibuprofen)* after the surgical procedures (Wessel and Tatakis, 2008). Post-operative results Post-operative swelling: It will be reported by the patients through the first week (7 days) postsurgically based on the Verbal Rating Scale (VRS) values (absent, slight, moderate and severe) (García et al., 2008). Surgery time Procedure as a whole

Inclusion Criteria: Patients complaining of Excessive gingival display (3mm or more gingival display at full smiling) Patients classified as Altered Passive Eruption Type 1A Exclusion Criteria: Patients need restorative or orthodontic correction. Pregnant and lactating females. Heavy smoker ≥ 10 cigarettes/day. Poor oral hygiene. Patients with systemic diseases which could influence the outcome of the therapy e.g. (Diabetic patients). Heavy smoker ≥ 10 cigarettes/day. Vulnerable groups of patients e.g. (prisoners, handicapped patients and decisionally impaired individuals)

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