The goal of this randomized controlled clinical study is to compare Fully digital to wax-up/mock-up guided esthetic crown lengthening procedure in management of excessive gingival display caused by altered passive eruption type 1B

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 mock-up guided method?

In today's world, the idea of smile and dental aesthetics extends beyond just the teeth. The fundamentals of a smile center on the interaction between the three key elements: the teeth, lips , and the gingiva.

Gummy smile (Excessive gingival display) is acknowledged by the American Academy of Periodontology (AAP) as a deformity and mucogingival problem that impacts the area surrounding the teeth

This condition may result from various 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 is described as "the gingival margin in adults is positioned incisal to the crown's cervical convexity and distanced from the tooth's cementoenamel junction."

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.

Esthetic crown lengthening (ECL) approach (both gingivectomy and bone removal) is used when less than 2 mm exists between the crest of the bone and the new gingival margin, and an adequate attached gingiva will remain after surgery (APE type IB).

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 crown lengthening procedures.

The major limitations with wax-up/ mock-up guided esthetic crown lengthening 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 ECL 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 ECL procedure could be produced.

The aim of the present study will be to evaluate accuracy and reliability of digital guided method of ECL procedure using CAD CAM technology versus conventional method using resin Mock-up as ECL surgical guide.

Inclusion Criteria:

• Patients who have Altered passive eruption (APE) type 1 B, according to classification of APE by Coslet et al.

Both genders aged from 20-50 years. Patients have thick gingival phenotype (thickness of gingiva is ≥ 1 mm) Patients should be systematically free from any disease.

Exclusion Criteria:

• Pregnant and lactating females.
• Heavy smoker ≥ 10 cigarettes/day.
• Poor oral hygiene.
• Patients with occlusal or malalignment problems.