Original study - ZZI 02/2011

Evaluation of the influence of preoperative factors
on soft tissue consolidation around single tooth implants
in the esthetic zone – A pilot study

C. K. Müller1, S. Fröbisch1, J. Chen2, S. Schultze-Mosgau1

Aim: The study aimed at identifying patient-, defect- and treatment-related factors that influence the esthetic outcome following oral rehabilitation using single tooth implant crowns.

Materials and Methods: 34 patients, who received a total of 49 dental implants at the Department of Oral and Maxillofacial Surgery/Plastic Surgery, Jena University Hospital, were analyzed in a pilot study. Patient-, defect- and treatment-related factors were documented. Employing the "Pink Esthetic Score" (PES), the "red esthetics" were judged on standardized intraoral photos. The influence of patient-, defect- and treatment-related factors on the PES score was analyzed in a multivariate statistical approach.

Results: Defect size, SAC class and the condition of periimplant bone were found to be significant variables in the description of the PES.

Conclusion: Within the limitation of a pilot study employing a small sample size, it was confirmed that insufficient hard and soft tissue represents the greatest challenge for the implantologist. Current developments in minimally invasive implantology might have the potential to enhance the esthetic outcome in the future.

Keywords: “red esthetics“; pink esthetic score; multivariate analysis

Introduction

The morphology of periimplant and periodontal tissue differs from that of marginal epithelium and supracrestal connective tissue. The periodontal marginal epithelium is thicker, has a greater amount of hemidesmosomes and is inserted further coronally than the periimplant marginal epithelium. Compared with the periodontal connective tissue, periimplant connective tissue is characterized by relative hypocellularity and poorer perfusion. Moreover, periimplant collagen fibers have a circular course, whereas around healthy teeth they insert into root cementum. The morphological differences between periimplant and periodontal tissue result in an increased tendency to inflammation of dental implants compared with healthy teeth [3, 26]. Contouring an optimally stable soft tissue sleeve at the implant emergence site is consequently of crucial importance for both the functional and the esthetic long-term success of an implant-borne restoration [25].

It is argued that different systemic and local factors influence soft tissue consolidation in the region of the implant emergence site and thus have a direct effect on esthetics [18, 22]. Underlying diseases such as diabetes mellitus and disorders of collagen metabolism and also certain long-term medications such as glucocorticoids are systemic factors that have a negative influence on the quality of the regenerated soft tissue. Local risk factors that interfere with normal soft tissue consolidation include smoking in particular, a history of radiotherapy [19], previous jaw reconstruction with microvascular anastomosis of the flap [17] and poor oral hygiene. Furthermore, the soft tissue management technique during augmentation, implant insertion and exposure appears to be extremely important for contouring the implant emergence site, and the surgeon can influence this directly [1, 30].

The aim of this study was to identify patient-, defect- and treatment-related factors that influence the esthetic outcome following oral rehabilitation using single tooth implant crowns.

 

Material and Method

Patients

The study was approved by the ethics committee of Jena University Hospital. All patients who received dental implants for oral rehabilitation at the Department of Oral and Maxillofacial Surgery/Plastic Surgery of Jena University Hospital between April 2005 and October 2007 were documented in a pilot study.

The following were the defined inclusion criteria: 1.) upper and lower implants in positions 1 to 5, 2.) prosthetic restoration by means of a single crown and 3.) at least one healthy reference tooth (anterior region: corresponding tooth on the opposite side; premolar region: neighboring tooth) in the same jaw. Patients who had previously had jaw reconstruction by means of a microvascular flap were excluded from the study.

 

Data collection

Age, gender and defect etiology (caries/periodontal lesions vs. aplasia vs. trauma) were recorded as patient-related factors.

The following were documented to describe the pre-treatment situation: implant position (upper vs. lower; single-tooth gap vs. saddle area with several neighboring implants), the condition of the periimplant hard tissue (implantation possible in local bone vs. bone augmentation with intraoral bone grafts vs. bone augmentation with iliac crest bone grafts) and the condition of the soft tissue (transmucosal healing possible vs. crestal incision [stretching] vs. oro-vestibular transposition flap vs. palatal roll vs. partial vestibuloplasty/apically positioned flap with free mucosal graft from the hard palate). The individual items were also examined for SAC classification (simple vs. advanced vs. complicated).

The treatment-related variables evaluated were the implantation concept (immediate vs. early, delayed immediate vs. late implantation, delayed immediate vs. late implantation) and treatment concept (immediate loading vs. increasing loading vs. late loading).

 

Photo analysis

Following prosthetic restoration, standardized intraoral photos were taken. All photos were taken with a digital camera (Nikon D 80, Mikro Nikkor lens with a focal length of 105 mm, ring flash or Speedlight SB 800). To ensure comparability, the reference tooth had to be clearly visible. Each photo was stored in 10x15 format with 300 dpi and a size of 5.99 megabyte.

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