HydroGraft for Mandibular Horizontal Ridge Atrophy Augmentation.

This randomized controlled trial aims to evaluate the efficacy of a hydrogel-enhanced allograft compared with a standard particulate allograft, both used in conjunction with a resorbable collagen membrane, for horizontal alveolar ridge augmentation in patients with mandibular Cawood and Howell Class IV ridge defects. The primary objective is to determine whether the hydrogel-enhanced allograft results in greater horizontal bone gain at 6 months following augmentation.

Inclusion Criteria: 1. Adults aged ≥18 years at the time of enrollment. 2. Cawood and Howell Class IV mandibular horizontal ridge atrophy (knife-edge ridge with sufficient height but inadequate width) at the anterior region. 3. Residual alveolar ridge width ≤ 4 mm measured on baseline CBCT at 3 mm below the alveolar crest at the planned augmentation site. 4. Adequate ridge height for planned implant length (≥ 10 mm from crest to vital structures or lower mandibular border). 5. ASA Physical Status Classification I or II. 6. Non-smoker, or former smoker who has quit ≥ 6 months prior to enrollment (verified by patient self-report). 7. Willingness to comply with the study protocol and attend all scheduled follow-up visits for the 6-month study duration. 8. Able to read, understand, and provide written informed consent in the language of the study site. Exclusion Criteria: 1. Uncontrolled systemic disease, including but not limited to: uncontrolled diabetes mellitus (HbA1c \>7.5% within 3 months of enrollment), uncontrolled hypertension, autoimmune disorders requiring immunosuppressive therapy. 2. Current smokers, or users of tobacco, e-cigarettes, smokeless tobacco, or other nicotine delivery products. 3. History of radiation therapy to the head and neck region. 4. Current or past (within 3 years) use of bisphosphonate therapy (oral or intravenous) or other antiresorptive/antiangiogenic agents (denosumab, bevacizumab). 5. Pregnancy or lactation at the time of enrollment, or planned pregnancy during the study period. 6. Active periodontal disease (untreated) at any site in the mouth; patients may be enrolled after completion of periodontal treatment and demonstration of disease stability. 7. Known allergy or hypersensitivity to collagen, or any component of the graft materials used in the study. 8. Previous bone augmentation procedure (GBR, block graft) at the planned study site. 9. Clinical or radiographic indication for simultaneous vertical ridge augmentation at the study site. 10. Inadequate oral hygiene: full-mouth plaque score \>25% after completion of the pre-surgical hygiene phase. 11. History of alcohol abuse or substance use disorder (per DSM-5 criteria) within the past 12 months.