In this study, participants with one lower first molar that require removal and replacement using dental implants will be enrolled. The implant will be inserted 12-16 weeks after tooth extraction and restored either immediately with an artificial tooth (fixed implant crown) in 50% of the cases or 4 weeks later in the remainder 50%. Immediate and early loading will be compared and the investigators expect no difference in terms of implant success and health of the tissue around the implant.

Background

Dental implants placed between 12 and 16 weeks after tooth loss are a well-documented treatment option. Placing the artificial tooth (implant crown) on the implant the same day (immediate loading) or approximately 4 weeks after implant placement (early loading) are also treatment options with good scientific documentation. Computer-assisted implant surgery (sCAIS) and modern implant materials/surfaces increase treatment predictability and success in this context.

Clinical relevance

The timing of implant placement post-extraction and subsequent implant loading cannot be separated in modern implant therapy any longer. At the "Sixth ITI Consensus Conference" in Amsterdam, it was concluded that the clinical evidence and documentation of early implant placement combined with immediate or early implant loading in partially edentulous patients is currently insufficiently documented. However, this treatment protocol seems to be widely applied in daily practice. The planned study is designed to provide evidence for the application of early implant placement with partial bone-healing and either an immediate or an early loading protocol.

Hypothesis/Specific aims

H0: "Early placed single tooth implants by means of static computer-assisted implant surgery (sCAIS) in mandibular first molar sites with immediately loaded provisionals, show a survival rate comparable to early placed implants with an early loading protocol." Secondary parameters to be evaluated will be the prosthetic survival/ success, patient-centered outcomes (PROs), clinical peri-implant conditions, bone-level changes, alteration of peri-implant soft-tissue dimensions and the accuracy of digital implant planning.

Inclusion Criteria:

• Age ≥ 20 years
• Willingness to sign informed consent and to participate in the study
• Plaque index according to Silness and Loe of < 35% [26]
• Presence of a mandibular first molar that has to be extracted
• Sufficient vertical interocclusal space for the placement of an implant crown (7 mm)
• Presence of an opposing natural or artificial tooth
• Ridge height sufficient for the placement of a ≥ 10 mm-long implant
• Sufficient ridge width for the placement of a 4.1mm diameter implant

Exclusion Criteria:

• Any physical or mental disorder that would interfere with the ability to perform adequate oral hygiene or the capability of providing written informed consent and compliance to the protocol
• Any disorder that would interfere with wound healing or represent a contraindication for implant surgery such as, but not limited to, uncontrolled diabetes or conditions resulting in or requiring immunosuppression, radiation, chemotherapy, frequent use of antibiotics or antiresorptive medication such as bisphosphonates
• Pregnancy or lactation
• Intention to become pregnant between inclusion and implant loading
• Heavy smoking habit with ≥ 10 cig/d
• Severe bruxism or clenching habits, present oro-facial pain
• Insufficient ridge width/height for the study implant
• Defect of any alveolar wall (secondary exclusion criterion at tooth extraction)
• ISQ < 70 (secondary exclusion criterion for Group A at implant placement, for Group B at loading visit)