The study protocol was approved by the Ethical Committee of the University of Zurich, Switzerland, and categorized as a study not being regulated by the law on human research in Switzerland (BASEC-Nr. Req-2019-01277, 20.12.2019, retrospectively registered). Signed informed consent was obtained from the patients included in this study.
Patients in need of a prosthetic rehabilitation were consecutively screened at the Clinic of Reconstructive Dentistry of the University of Zurich, Switzerland, and recruited for the present study. The patients were examined by experienced dentists, who took the intraoral scans and recorded the intraoral findings.
An intraoral scan (Trios, 3Shape, Copenhagen) with approximate true colors was obtained in all patients. The scan included a full-arch scan of both jaws including all teeth and a bite registration of both sides in occlusion. The computed scans were issued with a separate study number to pseudonymize the intraoral scans before being sent to the store-and-forward based server (portal.3shapecommunicate.com).
Detailed dental records were obtained including number and location of teeth, location of caries lesions, of non-carious cervical lesions (NCCL), and of erosive lesions. The location, size, and material of fillings and restorations were also recorded. In addition, tooth mobility [19] and tooth vitality by means of CO2 testing were assessed. A full-mouth periodontal examination (FMPE) was recorded including probing depth, attachment levels, plaque index [20], bleeding on probing [21], furcation involvement, and gingival recessions. Periapical radiographs were taken when clinically indicated.
The clinical data for each patient were captured in a standardized assessment form and served as control (Table 1). In brief, the amounts of plaque and calculus were rated using a scale with 5 scores, whereas dichotomized scores were applied for the parameters gingival recessions, furcation involvement, tooth erosion, tooth wear, stains and NCCL. The existence of decayed, filled, and crowned teeth as wells as the presence of implants was checked. In addition, the quality of the restorations was evaluated. Gingival and periodontal health were evaluated using a scale with 3 scores (healthy, localized, generalized).
Table 1: Remote scoring form including overview of patient-specific clinical conditions
(P= patient; n=10 patients)
|
Score
|
Criteria
|
|
|
|
|
|
|
|
|
|
|
Clinical indices
|
|
|
P1
|
P2
|
P3
|
P4
|
P5
|
P6
|
P7
|
P8
|
P9
|
P10
|
Plaque
|
0
|
No plaque
|
|
|
|
|
|
|
|
|
|
|
1
|
Little amounts of plaque (less than 20% of the tooth surfaces covered with plaque)
|
x
|
|
x
|
x
|
|
|
|
x
|
|
|
2
|
Moderate amounts of plaque (less than 50% of the tooth surfaces covered with plaque)
|
|
|
|
|
|
x
|
|
|
|
x
|
3
|
High amounts of plaque (less than 80% of the tooth surfaces covered with plaque)
|
|
|
|
|
x
|
|
x
|
|
x
|
|
4
|
Generalized plaque
|
|
x
|
|
|
|
|
|
|
|
|
Calculus
|
0
|
No calculus
|
|
|
|
x
|
|
|
|
|
|
x
|
1
|
Little amounts of calculus (limited to the lingual surfaces of the lower front teeth)
|
x
|
|
x
|
|
x
|
x
|
x
|
x
|
|
|
2
|
Moderate amounts of calculus (limited to the lingual surfaces of the lower front teeth and the buccal surfaces of the maxillary molars)
|
|
|
|
|
|
|
|
|
|
|
3
|
High amounts of calculus (involvement of more tooth surfaces than the ones of the lower front teeth and the maxillary molars)
|
|
x
|
|
|
|
|
|
|
x
|
|
4
|
Generalized calculus
|
|
|
|
|
|
|
|
|
|
|
Gingival recessions
|
0
|
No recessions
|
|
|
|
x
|
x
|
x
|
|
|
|
|
1
|
Presence of recessions
|
x
|
x
|
x
|
|
|
|
x
|
x
|
x
|
x
|
Furcation involvement
|
0
|
No teeth with furcation involvement
|
|
|
x
|
x
|
x
|
x
|
|
|
|
|
1
|
Presence of teeth with furcation involvement
|
x
|
x
|
|
|
|
|
x
|
x
|
x
|
x
|
Erosions
|
0
|
No erosions
|
x
|
x
|
|
|
|
|
x
|
x
|
x
|
x
|
1
|
Presence of erosions
|
|
|
x
|
x
|
x
|
x
|
|
|
|
|
Tooth wear
|
0
|
No signs of tooth wear
|
|
|
|
|
|
|
|
|
|
|
1
|
Presence of tooth wear
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
Stains
|
0
|
No stains
|
|
|
|
|
x
|
|
|
|
|
|
1
|
Presence of stains
|
x
|
x
|
x
|
x
|
|
x
|
x
|
x
|
x
|
x
|
Non-carious cervical lesions (NCCL)
|
0
|
No NCCL
|
|
|
|
|
x
|
|
|
|
|
x
|
1
|
Presence of NCCL
|
x
|
x
|
x
|
x
|
|
x
|
x
|
x
|
x
|
|
Dentition
|
|
|
|
|
|
|
|
|
|
|
|
|
Decayed teeth
|
0
|
No decayed teeth
|
x
|
|
x
|
x
|
x
|
|
|
|
x
|
|
1
|
Presence of decayed teeth
|
|
x
|
|
|
|
x
|
x
|
x
|
|
x
|
Filled teeth
|
0
|
No filled teeth
|
|
|
|
|
|
|
|
|
|
|
1
|
Presence of filled teeth
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
1a
|
Sufficient (no intervention needed)
|
|
|
|
|
|
|
|
|
|
|
1b
|
At least one filling insufficient (need for intervention)
|
|
|
|
|
|
|
|
|
|
|
Crowned teeth
|
0
|
No crowned teeth
|
|
x
|
x
|
x
|
x
|
x
|
|
|
|
|
1
|
Presence of crowned teeth
|
x
|
|
|
|
|
|
x
|
x
|
x
|
x
|
1 a
|
Sufficient (no intervention needed)
|
|
|
|
|
|
|
|
|
|
|
1 b
|
At least one crowned tooth insufficient (need for intervention)
|
|
|
|
|
|
|
|
|
|
|
Implants
|
0
|
No implants
|
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
x
|
1
|
Presence of implants
|
x
|
|
|
|
|
|
|
|
|
|
Diagnosis
|
|
|
|
|
|
|
|
|
|
|
|
|
Gingivitis
|
0
|
No gingivitis
|
|
|
|
|
|
|
|
|
|
|
1
|
Localized gingivitis (less than 30% of the teeth involved)
|
x
|
|
x
|
x
|
x
|
x
|
|
|
x
|
x
|
2
|
Generalized gingivitis (more than 30% of teeth involved)
|
|
x
|
|
|
|
|
x
|
x
|
|
|
Periodontitis
|
0
|
No periodontitis
|
|
|
x
|
x
|
x
|
x
|
|
|
|
|
1
|
Localized periodontitis (less than 30% of the teeth involved)
|
x
|
|
|
|
|
|
x
|
|
x
|
x
|
2
|
Generalized periodontitis (more than 30% of teeth involved)
|
|
x
|
|
|
|
|
|
x
|
|
|
For this validation study, ten patients were selected. The sample of patients was created to represent a wide variety of different clinical situations (Figure 1). Edentulous patients and patients presenting with Kennedy class 1 were excluded. The overview of the clinical characteristics of the ten patients is presented in Table 1.
The remote examiners, who had a minimum of three years of experience as general practitioners, assessed the intraoral scans on a tablet computer (iPad Air, model A1474, Apple Corp. Cupertino, CA) using the software app provided by the manufacturer (3Shape Communicate, Version 4.0.1). The examiners used the standardized assessment form during the tele examination. Thereafter, they were provided with the periapical radiographs and asked to provide a second round of tele assessment. The time for the tele examination was recorded for assessment of the intraoral scans as well as for the additional assessment with the radiographs. The remote scoring (test) was compared to the scoring derived from the clinical data (control).
Each of the 10 patients was scored remotely by 10 examiners resulting in a total of 100 observations per parameter. Data was coded in Microsoft Excel. Analyses and illustrations were generated with the statistical software R [22], including the package ggplot2 [23]. For the parameters plaque and calculus dentists were grouped according to their years of clinical experience (less than 5 years of clinical experience versus more than 5 years of clinical experience).