Success of Implant Restorations After Immediate or Delayed Implant Placement With/Without Ridge Preservation

This is a prospective, parallel-group, randomized study aiming to compare clinical, radiographic, PROMS and health-economic outcomes of type I, type II and type III/IV (in socket preserved areas) implant placement.

This study included three groups:

i. Immediate implant placement + aputogenous connective tissue graft (CTG) (type I).

ii. Early implant placement (type II, after 6-8 weeks). iii. Delayed/late placement in socket-preserved sites (type III/IV, after 3-6 months).

Up 75-90 adult, systemically healthy patients will be recruited mainly in the new patient and follow-up implant clinics which run every week at the Murcia University Dental Hospital Morales Meseguer. In addition, patients with unrestorable maxillary premolars, canines and incisors will be recruited from other relevant clinics within the same hospital, such as Periodontics, Endodontics/Dental Trauma Restorative Dentistry, Oral Surgery and Hypodontia outpatient clinics. Flyers advertising the study will also be placed in the Hospital and in the reception area to be visible.

After screening patients, the potentially eligible participants will be given the patient information sheet and they will be invited to attend the enrolment visit at Murcia University Dental Hospital Morales Meseguer . Before any study-related intervention is performed, informed consent will be obtained. During the enrolment visit, a detailed medical history will be taken and the periodontal parameters adjacent to the tooth to replace will be recorded. The GDP will be sent a letter to inform him/her about the enrolment of their patient in the study and about the need for any dental treatment (if needed).

Below is a summary of all study visits for each study group:

• For type-I placement:

Visit 1: Screening and oral hygiene improvement, non-invasive imaging baseline (intraoral scanning, pre-extraction CBCT) and impressions for temporary replacement.

Visit 2: Extraction, CBCT post extraction and provision of immediate implant. Visit 3: Suture removal. Visit 4: Provision of second stage surgery after 12-14 weeks. Visit 5: Impressions for temporary restoration after 2 weeks. Visit 6: Provision of temporary restoration after 2-4 weeks. Visit 7: Impressions for final restoration after 3-6 months. Visit 8: Provision of final implant restoration. Visit 9: Final visit for data collection at 12 months post-loading and CBCT.

• For type-II placement:

Visit 1: Screening and oral hygiene improvement, non-invasive imaging baseline (intraoral scanning, pre-extraction CBCT) and impressions for temporary replacement.

Visit 2: Extraction, CBCT post extraction. Visit 3: Suture removal after 1-2 weeks. Visit 4: Provision of type II placement after 6-8 weeks. Visit 5: Suture removal after 1-2 weeks. Visit 6: Provision of second stage surgery after 12-14 weeks. Visit 7: Impressions for temporary restoration after 2 weeks. Visit 8: Provision of temporary restoration after 2-4 weeks. Visit 9: Impressions for final restoration after 3-6 months. Visit 10: Provision of permanent implant restoration. Visit 11: Final visit for data collection at 12 months post-loading and CBCT.

• For socket-preserved sites with type-III/IV placement:

Visit 1: Screening and oral hygiene improvement, non-invasive imaging baseline (intraoral scanning, pre-extraction CBCT) and impressions for temporary replacement.

Visit 2: Extraction, CBCT post extraction and provision of ARP. Visit 3: Suture removal after 1-2 weeks. Visit 4: Visit 5: Provision of type III/IV placement after 12-24weeks. Visit 5: Suture removal after 1-2 weeks. Visit 6: Provision of second stage surgery after 12-14 weeks. Visit 7: Impressions for temporary restoration after 2 weeks. Visit 8: Provision of temporary restoration after 2-4 weeks. Visit 9: Impressions for final restoration after 3-6 months. Visit 10: Provision of final implant restoration. Visit 11: Final visit for data collection at 12 months post-loading and CBCT.

Inclusion criteria

i) Patient must have willingness to read and sign a copy of the Informed Consent Form Males and females, ≥23 years old.

ii) Patient in need of a single permanent tooth extraction with clinical and/or radiographic evidence of unrestorable maxillary premolars, canines, or incisors with at least one adjacent tooth present, and with periodontal attachment preserved at least for two thirds of the root not associated with acute periapical pathology.

iii) Post-extraction alveolar bone defect with ≤50 % buccal bone loss. This will be confirmed at Visit 2 after extraction. In case of >50% buccal bone loss, the participant will be withdrawn from the study.

iv) Patient in good general health as documented by self-assessment. v) Full mouth bleeding and plaque scores (FMBS <10% and FMPS <30%) recorded within the previous 8 weeks.

Exclusion criteria

i) Uncontrolled or untreated periodontal disease. ii) History of local (head and neck) radiation therapy. iii) Presence of oral lesions in the area of the extraction (such as ulceration, malignancy).

iv) Severe bruxing or clenching habits. v) Acute endodontic lesion in the test tooth or in the neighbouring areas to the extraction procedure (sites with presence of an asymptomatic chronic lesion are eligible).

vi) Medical history that includes uncontrolled diabetes or hepatic or renal disease, or other serious medical conditions that can impact on bone metabolism (e.g. rheumatoid arthritis, osteoporosis) or transmittable diseases (e.g. AIDS).

vii) History of alcohol or drug abuse. viii) Smokers. ix) Self-reported pregnancy or lactation (this criterion is due to oral tissue changes related to pregnancy and nursing which can affect interpretation of study results).

x) Other severe acute or chronic medical or psychiatric condition or laboratory abnormality that may increase the risk associated with trial participation or investigational product administration or may interfere with the interpretation of trial results and, in the judgement of the investigator, would make the subject inappropriate for entry into this trial.

xi) Malocclusion, or collapse of the occlusal vertical dimension leading to dentoalveolar compensation which could interfere with ridge preservation dimensions and measurements.

xii) Lack of adjacent sound restored or unrestored teeth.