Incidence of Straight-Channel Screw-Retained Single Crown Following Immediate Implant Placement and Provisionalization in the Esthetic Zone: A CBCT Study.

PURPOSE: The purpose of this cone beam computed tomography (CBCT) study was to investigate the probability of using straight screw-channel screw-retained restorations following an immediate implant placement and provisionalization protocol in maxillary anterior teeth utilizing implant planning software. MATERIALS AND METHODS: A retrospective review of CBCT images was done. The midsagittal images of maxillary anterior teeth (right canine to left canine) were created in implant planning software, screen-captured, and transferred to a presentation program. The digital implant templates were created for 3.5-mm-diameter (used for central and lateral incisors) and 4.5-mm-diameter (used for central incisors and canines) tapered implants with lengths of 13, 15, and 18 mm. The frequency percentages of immediate implant placement and provisionalization and immediate implant placement and provisionalization with straight screw-channel screw-retained restorations were recorded and compared among all maxillary anterior teeth. RESULTS: CBCT images from 1,200 teeth were evaluated. The overall frequency percentages of immediate implant placement and provisionalization and immediate implant placement and provisionalization with straight screw-channel screw-retained restoration were 84% (range = 74% to 92%) and 14% (range = 10% to 24%), respectively. CONCLUSION: Although the probability of being able to employ immediate implant placement and provisionalization with a straight screw-channel screw-retained restoration in the esthetic zone is low, the use of smaller-diameter implants can substantially increase the probability.

Restorative Emergence Profile for Single-Tooth Implants in Healthy Periodontal Patients: Clinical Guidelines and Decision-Making Strategies.

The peri-implant soft tissue seal consists of a connective tissue cuff and a junctional epithelium that is different from the arrangement of periodontium around a natural tooth. However, the peri-implant soft tissue complex lacks Sharpey's fibers, thus offering less resistance to clinical probing and biofilm penetration compared to the natural dentition. Therefore, the proper restorative emergence profile design is essential to facilitate favorable esthetic outcomes and maintain peri-implant health. The aim of this article is to review the currently available evidence related to the design of subgingival (critical and subcritical) and supragingival contours of the implant restorative emergence profile (IREP) as well as provide a flowchart for decision-making in clinical practice. Theoretically, the subgingival contours of the crown/abutment complex should mimic the morphology of the root and the cervical third of the anatomic crown as much and as often as possible. However, this is highly dependent upon the three-dimensional spatial position of the implant relative to the hard and soft tissue complex, in addition to the location of the definitive restoration. Frequently, a convex critical contour is required on the facial aspect of a palatally or incisally positioned implant to support an adequate gingival-margin architecture. Conversely, if the implant is placed too far facially, then a flat or concave contour is recommended. In instances where soft tissue support is not needed, the subcritical area may be undercontoured to increase the thickness, height, and stability of the soft tissue cuff.

Accuracy of Bone Sounding in Assessing Facial Osseous-Gingival Tissue Relationship in Maxillary Anterior Teeth.

The aim of this study was to evaluate the accuracy of bone sounding (BS) in assessing the facial osseous-gingival tissue relationship (FOGTR) of failing maxillary anterior teeth. Dental records of patients who received immediate implant placement (IIP) at the maxillary anterior area were screened. Mid-FOGTR prior to extraction (BS), and immediately after flapless extraction (direct bone level [DBL] measurement) were analyzed. A total of 160 patients with 190 maxillary anterior teeth were included. The mean FOGTR obtained from BS and DBL were 3.19 ± 0.71 mm and 3.47 ± 1.29 mm, respectively (P = .004). The two measurements were identical 83.2% of the time, within 1-mm discrepancy 4.7% of the time, and > ± 1 mm discrepancy 12.1% of the time. When discrepancy was observed, BS underestimated DBL 14.2% of the time and overestimated 2.6% of the time. Though statistically significant, the correlation was weak (Pearson correlation coefficient r = .238, P = .0018). BS is an acceptably accurate and minimally invasive diagnostic tool for measuring FOGTR. However, while the mean difference between BS and DBL measurement is small (0.28 mm), the large range of difference can be alarming. Therefore, clinicians should always prepare alternative treatment options for IIP prior to extraction.

Effects of implant morphology on rotational stability during immediate implant placement in the esthetic zone.

PURPOSE: Primary implant stability is critical to achieving implant success, especially in a situation with immediate implant placement and provisionalization (IIPP) when bone quality and quantity are compromised. The purpose of this study was to examine the effects of implant morphology (tapered vs cylindric) and the final drill-implant diameter discrepancy (FD-IDD) of six implant systems on the incidence of rotational instability during IIPP in the esthetic zone. MATERIALS AND METHODS: One hundred seventy-one implants in 112 patients were evaluated. Implants that exhibited inadequate resistance to the torque generated by the surgeon's hand during implant placement were classified as rotationally unstable. RESULTS: The overall incidence of rotational instability for the tapered implants (1.1%) was significantly lower than that exhibited by the cylindric (nontapered) implants (20.5%). Among the cylindric implants, those with < 0.5 mm FD-IDD experienced a significantly higher incidence of rotational instability (36.6%) than groups with ≥ 0.5 mm FD-IDD. The incidence of rotational instability of cylindric implants with ≥ 0.5 mm FD-IDD was significantly greater than that of the tapered implants with a comparable FD-IDD. CONCLUSION: Within the confines of this study, the use of a tapered implant with an FD-IDD of ≥ 0.5 mm minimized the incidence of rotational implant instability for the IIPP procedure.