Distance to bone
The distance between the apical aspect of the interproximal contact and the interdental bone crest and its relationship with papilla height between a single implant and its adjacent natural tooth has also been examined. When the distance from the contact point to the crest of bone was ≤ 5 mm, the papilla was present 100% of the time. However, when the distance was ≥ 6 mm, the papilla was present in only 50% or fewer of the cases.185 These results are very similar to the previous study evaluating papillae height around natural dentition,101 indicating that the bone crest of the adjacent teeth determines the papilla level around single implant-supported crowns.139,184 These studies highlight the importance of maintaining and preserving the interproximal crestal bone of adjacent teeth next to the single implant to maintain optimal papilla levels.
According to a recent systematic review, the distance from the contact point to the underlying interproximal bone was the most significant factor associated with papilla fill.139 The sites with complete papilla fill had a mean distance of 4.7 ± 0.9 mm from contact point to the underlying interproximal bone. Therefore, re-creation of the “full” papilla around single implants is predictable when the distance from the contact point to the bone crest is ≤ 5 mm.184,185
Distance to teeth
With regard to implant-tooth distance, the presence of papillae filling the entire proximal space was strongly related to an implant-tooth distance of 2.5 to 4.0 mm.181 Based on Tarnow et al’s finding of 1.4 mm of lateral bone remodeling, a minimal distance of 1.5 to 2.0 mm is desirable from the implant to the adjacent root surface for an acceptable presence of the papilla, because the bone crest of the adjacent teeth determines the papilla level around single implant-supported crowns.147
Jemt proposed a papilla index evaluating the degree of papilla fill in the interproximal embrasure space formed between single implant-supported restorations and adjacent natural teeth.186 It consists of five different categories: score 0, no papilla present; score 1, less than half the height of the papilla is present; score 2, at least half the height of the papilla is present; score 3, the entire embrasure space is occupied by papilla and in good harmony with adjacent papillae; score 4, hyperplastic papilla.
Spontaneous regeneration of the papilla can occur after restoration of the implant, with significant esthetic improvement possible over time.182,186–188 An early study reporting on the natural regeneration of the papilla over a mean 1.5 years of follow-up from the time of crown delivery showed an improvement of the Jemt score. The score improved from about 1.5 to about 2.5, indicating substantially more gingival embrasure fill. Moreover, significant improvement over time was noted in regard to complete papilla fill. A score of 3 was only assigned to 10% of the papillae at the time of crown placement, but after several years’ follow-up, a score of 3 was seen for 58% of the papillae.186 Papilla fill adjacent to implants receiving conventional healing abutments or provisional restorations has been evaluated as well. Prior to delivery of the definitive crown, the provisional crown may restore the soft tissue volume faster than the healing abutment. However, a similar volume of soft tissue was noted after 2 years in function. Given time, there was no significant difference between the two single-implant groups.188
Papillae between adjacent implants
Developing a normal interdental papilla between two adjacent implants for an implant-supported restoration is significantly more challenging than developing one around a single implant-supported restoration adjacent to natural teeth. Similarly to the papilla around a single implant-supported restoration, it can be influenced by several factors such as the distance between the crest of bone and the contact point, the interim-plant distance, and the definitive crown shape (Fig 1-16).
Fig 1-16 Occlusal view of adjacent implants replacing mandibular premolars and the corresponding soft tissue contours, demonstrating the challenge of creating an ideal interproximal papilla between the implants.
Distance from the crest of the bone to the contact point
The mean average distance from the tip of the papilla to the crest of bone between two adjacent implants was 3.4 mm. The most common recordings were 3 mm (35.3%) or 4 mm (37.5%).189 A distance of 3 to 4 mm (and never more than 6 mm) from the contact point to the bone crest is recommended to facilitate esthetic success, defined as a score of 2 or 3 according to the Jemt index186 (at least half to full height of the proximal area occupied by soft tissue).182
When two adjacent teeth must be replaced in the esthetic zone, careful evaluation should precede implant placement. Many treatment strategies have been proposed to address this esthetic challenge, and treatment modification may be needed. This challenge is amplified when the site to be restored is adjacent to the facial midline. This may result in an accentuated sagittal asymmetry of the patient’s anterior dentogingival complex, especially for a patient with a high smile line. One suggestion is to perform vertical bone augmentation prior to implant placement. The implants are then placed at least 3 mm apart to maintain the vertical bone height. Another choice is to place only one implant, incorporating an ovate cantilever pontic on the adjacent site. Simultaneous soft tissue augmentation may allow better simulation of the interproximal papilla.189 Another variation is to harvest soft tissue from the tuberosity, which is then positioned in the area of soft tissue deficiency at the time of abutment connection for re-creation of the papilla.190
Interimplant distance
Careful planning of the interimplant and implant-tooth distance is an important strategy to achieve ideal papilla height. Vertical bone remodeling around the implants with expected loss of 1.5 to 2.0 mm in the first year after implant placement is very well established.191 Bone loss around implants also occurs in a radiographically horizontal direction (1.34 mm for the mesial and 1.4 mm for the distal surface of the implant). This is actually circumferential change. When adjacent defects meet, crestal vertical bone loss occurs. Crestal bone loss of 1.04 mm was noted if the interimplant distance was ≤ 3 mm, while bone loss of 0.45 mm occurred when the distance was greater than 3 mm. The greater the crestal bone loss, the greater the distance from the contact point to the crest of the bone. This finding has led several authors to recommend a minimal distance of 3 mm when placing adjacent implants to maintain papilla fill.147
Similar results were observed in an animal study in which two adjacent implants were placed 2 or 3 mm apart. The contiguous implants were restored, and the mean distance from the contact point to the bone crest was 6 mm and from the papilla tip to the bone crest 3.3 mm.192 The authors concluded that these distances were similar in both groups. Therefore, the ideal distance from the contact point to the bone crest should be less than 5 mm. At least 3 to 4 mm may compensate for crestal bone remodeling and establishment of desirable papilla fill between two adjacent implants.
This minimum distance may be influenced by different implant designs. One clinical study evaluated vertical and horizontal bone remodeling around two adjacent platform-switched implants placed less than 3 mm (2.23 ± 0.55 mm) apart. These had been restored