Immediate or Delayed Provisionalization in Posterior Healed Sites

In this study, the investigators will examine the performance of a new dental implant that has been approved by the Food and Drug Administration for use to replace of missing teeth. The investigators will study two groups of patients: one group will receive a temporary crown to replace the missing tooth at the same day as implant surgery; the second group will receive a similar crown 3 months later. Both groups will receive a permanent crown on the implant 4 months after surgery, and will be followed up for a period of 12 months. The investigators want to examine whether the healing of the bone and gums surrounding the implant that receives a crown immediately is similar to the healing of the implant when the crown is delivered later. If this is indeed the case, then the investigators will be able to recommend faster treatment for all patients.

Dental implants are a widely used treatment option for the replacement of lost teeth due to trauma or oral diseases. The original protocol for placement of dental implants in edentulous spaces in the maxilla or the mandible was introduced more than thirty years ago and called for a two-stage approach, i.e., surgical placement of submerged dental implants and subsequent uncovering with abutment connection, prosthesis fabrication and functional loading approximately 6 months after. Today, the time between surgery and loading in a two-stage protocol has been commonly abbreviated to 3-4 months, while immediate implant provisionalization has emerged as a reliable and predictable option in cases of adequate osseous support, having similar survival and success rates to the two-step procedure. Comparison of histological healing has demonstrated no significant differences in bone to implant contact between implants surgically placed according to a two-stage protocol and those immediately provisionalized. However, substantial variability was noted among the clinical protocols used in the studies carried out so far, and additional well-designed randomized controlled trials (RCTs) are needed to fully appreciate the clinical outcomes of immediate and early loading protocols.

The design of dental implants is a subject of continuous improvement, and implant manufacturers regularly introduce new products the use of which may result in accelerated soft and hard tissue healing, increased initial implant stability, and enhanced aesthetic outcomes. The purpose of this randomized, controlled trial is to compare treatment outcomes when using a newly-introduced dental implant (NobelParallel™ CC) in a one-stage or a two-stage protocol. This new implant has the same titanium oxide surface coating (TiUnite®) and the same design principles of the parallel-walled NobelSpeedy Groovy™ implants, and an internal conical connection. The implant is marketed under the premarket notifications K050406 and K073142 (510(k), Food and Drug Administration).

Eligibility Criteria:
Inclusion Criteria:

* 50 subjects will be recruited among those referred to the Columbia University College of Dental Medicine for tooth replacement using a dental implant in a posterior maxillary or mandibular region (premolar/molar area)
* Age 18 or older
* Healed extraction sockets (extraction carried out at least 3 months prior to recruitment)
* Implant site free of infection
* Systemically healthy patients or with controlled common systemic conditions
* Adjacent teeth present both mesially and distally to the implant site

Exclusion Criteria:

* Pregnancy or intent to be pregnant over the next 12 months
* Current smoking exceeding 10 cigarettes/day
* Parafunctional habits/ excessive occlusal forces
* Current orthodontic therapy
* Uncontrolled hypertension (blood pressure over 160/100) or poorly-controlled diabetes (HbA1c\>8%)