Software-supported periodontal diagnostics with three-dimensional cone-beam computed tomography compared to conventional two-dimensional panoramic imaging and clinical diagnostics (a prospective study).

AIM: Aim of this study comprised the software-supported evaluation of measurement accuracy between cone-beam computed tomography (CBCT) and panoramic radiographs in the assessment of the periodontal bone level in patients with periodontitis and comparison with clinical periodontal parameters. MATERIAL AND METHODS: Twenty patients with severe periodontitis (stage III-IV) were evaluated clinically and radiographically (panoramic and CBCT). Diagnostic interpretation comprised three blinded investigators with different levels of experience. Specific software-basing measurement procedure evaluated radiological distances for the mesial, central, and distal bone levels on the oral and vestibular sides of the teeth investigated and furcation upper and lower boundary. Jaw localization, anatomical region-of-interest, the number of roots and experience of the observers were evaluated. All measurements were carried out twice by the same observers within a 6-week interval. RESULTS: Slightly higher measurement deviations (SD) in the range of 0.47 (0.40) mm were found for CBCT evaluation compared to panoramic imaging. Pearson correlation analysis showed statistically strong positive correlation for the mesial and distal aspects, moderate positive correlation was found for the investigated furcations between both radiographic modalities. Compared to the clinical reference, the mean total error of measurement (SD) was larger for panoramic imaging (0.66 (0.48) mm) than CBCT (0.27 (0.08) mm) for all three observers. CONCLUSIONS: Software-supported CBCT analysis delivers better diagnostic information about the bony periodontal conditions of the patient compared to two-dimensional radiographs. However, it remains unclear if these additional information lead to better periodontal outcomes.

Radiographic Bone Loss and Its Relation to Patient-Specific Risk Factors, LDL Cholesterol, and Vitamin D: A Cross-Sectional Study.

The influence of patient-specific factors such as medical conditions, low-density lipoprotein cholesterol (LDL-C) or levels of 25-hydroxyvitamin D (25OHD) on periodontal diseases is frequently discussed in the literature. Therefore, the aim of this retrospective cross-sectional study was to evaluate potential associations between radiographic bone loss (RBL) and patient-specific risk factors, particularly LDL-C and 25OHD levels. Patients from a dental practice, who received full-mouth cone beam CTs (CBCTs) and blood-sampling in the course of implant treatment planning, were included in this study. RBL was determined at six sites per tooth from CBCT data. LDL-C and 25OHD levels were measured from venous blood samples. Other patient-specific risk factors were assessed based on anamnesis and dental charts. Statistical analysis was performed applying non-parametric procedures (Mann-Whitney U tests, error rates method). Data from 163 patients could be included in the analysis. RBL was significantly higher in male patients, older age groups, smokers, patients with high DMFT (decayed/missing/filled teeth) score, lower number of teeth, and high LDL-C levels (≥160 mg/dL). Furthermore, patients with high 25OHD levels (≥40 ng/mL) exhibited significantly less RBL. In summary, RBL was found to be associated with known patient-specific markers, particularly with age and high LDL-C levels.

Resorption of retromolar bone grafts after alveolar ridge augmentation-volumetric changes after 12 months assessed by CBCT analysis.

In this pilot study, a volumetric analysis of retromolar onlay bone grafts over a period of 12 months was conducted, using repeated CBCT imaging combined with automated image registration.Eleven patients being treated with 16 bone grafts taken from the retromolar area were examined by CBCT scanning prior to bone augmentation (T0), immediately after bone augmentation (T1) and after a healing time of 12 months after augmentation (T2). Graft volumes were measured at each time point after automated image registration of consecutive CBCT scans.The mean volume of the augmented site was 372.2 ± 179.4 mm3. Resorption relative to the original augmented volume was 43.7% ± 19.0% after 12 months.Three-dimensional graft resorption could be precisely depicted by the use of automated image registration for CBCT data over a period of 12 months and demonstrated extensive volumetric changes of bone grafts taken from the ascending ramus of the mandible.Graft resorption and continuous bony remodeling of the grafted site before and after implant insertion have to be carefully considered by the clinician.

Accuracy and Usefulness of CBCT in Periodontology: A Systematic Review of the Literature.

A systematic literature review was performed regarding the accuracy and usefulness of cone beam computed tomography (CBCT) in the field of periodontology. A total of 580 articles were identified, of which 13 met the inclusion criteria. Results showed a high accuracy of CBCT in visualizing periodontal structures and the demonstrated the usefulness of CBCT in regenerative periodontal surgery of maxillary molars. It remains questionable whether this gain of additional information actually leads to a better clinical outcome in periodontal treatment. Currently, the use of CBCT in periodontology should be restricted to complex periodontal cases, particularly those involving maxillary molars.

Comparison of two cone-beam computed tomography systems in the visualization of endodontic structures.

An important part of endodontic diagnosis and treatment is the adequate visualization of root canal anatomy. The objective of the present study was to compare two different three-dimensional cone-beam computed tomography (CBCT) systems, Scanora 3D and 3D Accuitomo 170, with respect to their visualization of endodontic canal systems and potential pathological alterations. Seventy extracted human teeth were investigated with regard to the radiographic detection of number of root canals, lateral canals, root canal fillings and posts, vertical root fractures, and the occurrence of image artifacts. For each evaluation parameter under investigation the radiographic diagnoses obtained by the two different CBCT systems under investigation were similarly accurate, without statistically significant differences. The evaluation of teeth containing highdensity foreign materials was impaired for both CBCT systems because of image artifacts. However, a difference between the CBCT systems was not observed. In conclusion, both CBCT systems were found to be similarly suitable for the visualization of endodontic structures in vitro.

Alumina reinforced zirconia implants: 1-year results from a prospective cohort investigation.

OBJECTIVE: The objective of this investigation was to determine the clinical and radiographic outcome of a one-piece alumina-toughened zirconia (ATZ) oral implant for single tooth replacement after 1 year. MATERIALS AND METHODS: A total of 27 patients received one ATZ implant each in a one-stage implant surgery with immediate temporization. Standardized radiographs were taken at implant insertion and after 1 year to monitor peri-implant bone loss. Several soft tissue parameters were evaluated at prosthesis insertion and at the 1-year follow-up. RESULTS: Three patients did not receive a prosthetic reconstruction due to implant loss during the healing period. As a result, 24 patients were seen at the 1-year follow-up, giving a cumulative survival rate of 88.9%. The average marginal bone loss after 1 year was 0.77 mm. Only two implants (8.3%) lost at least 2 mm bone, whereas none of the implants lost more than 3 mm. Probing depth and clinical attachment level increased over 1 year at the implant sites, whereas gingival recession remained stable. Mombelli's bleeding and plaque indices showed no statistically significant change within the first year. CONCLUSION: Owing to a total of 27 inserted implants, three failures within the first 4 months after implant placement carry weight. Therefore, the cumulative survival rate of the presented ceramic implant was slightly below reported survival rates of titanium implants when immediately restored. The recorded radiographic bone loss and peri-implant soft tissue parameters showed promising short-term results. The presented ATZ implant seems to be a candidate for clinical usage.

Ridge preservation after ridge expansion with simultaneous guided bone regeneration: a preclinical study.

OBJECTIVE: To evaluate ridge preservation after ridge splitting with simultaneous implant placement and guided bone regeneration (GBR) in a miniature pig model. MATERIAL AND METHODS: In miniature pigs, the mandibular premolars and first molars were extracted together with removal of the interdental and buccal bone. Three months later, ridge splitting and expansion of the buccal plate were performed with simultaneous placement of two titanium implants per quadrant. On the test side, access by a mucoperiosteal flap followed by GBR with a biphasic calcium phosphate and a collagen membrane was performed. On the contralateral control side, a mucosal flap (MF), leaving the periosteum attached to the buccal bone, was elevated. After healing periods of 6 and 12 weeks, eight and four animals, respectively, were sacrificed for histological and histometric evaluation. RESULTS: In the MF group, all 16 implants were osseointegrated, while in the GBR group, one bone fracture occurred, and six of 16 implants were lost. After 6 weeks, significantly higher bone crest levels were found for the GBR group than for the MF group both buccally and lingually (P < 0.001), and buccal bone thickness was greater in the GBR group than in the MF group (P < 0.001 at the implant shoulder [IS]). After 12 weeks, bone was significantly higher in the GBR group compared to the MF group. Furthermore, buccal bone thickness in the GBR group was 0.93, 4.5, and 5.94 mm at, and 2 and 4 mm apical to the IS, respectively. The corresponding values in the MF group were greatly reduced (0, 0.21, and 2.56 mm). Bone loss on the buccal side compared to the lingual side was significantly greater only in the MF group. CONCLUSIONS: In this ridge expansion model in miniature pigs, the buccal bone volume was significantly better preserved with GBR when compared to a mucosal access flap, provided that soft tissue healing occurred complication free.

Possibilities and limits of imaging endodontic structures with CBCT.

An adequate portrayal of the root canal anatomy by diagnostic imaging is a prerequisite for a successful diagnosis and therapy in endodontics. The introduction of dental cone beam computed tomography (CBCT) has considerably expanded the scope of imaging diagnostics. The aim of the following study was to evaluate the imaging of endodontic structures with CBCT. One hundred and twenty teeth were examined with a CBCT device (ProMax 3D). Subsequently, the findings of the three-dimensional images were evaluated and compared to those of dental radiographs and tangential section preparations of the examined teeth. Results with high prevalence, such as existing roots and root canals, as well as results with low prevalence, e.g., extremely fine anatomical structures of the endodontic tissue, could be visualized precisely by dental CBCT; side canals, ramifications, communications, pulp stones, and obliterations could also be detected. Additionally, the length of curved root canals could be determined accurately. Likewise, root fractures were visualized reliably with CBCT. However, carious lesions could not be diagnosed adequately, and the evaluation of fillings and prosthetic restorations was complicated due to scattered X-ray artifacts. CBCT datasets qualify to visualize and diagnose small anatomical structures of the endodontic tissue.

Bone loss after ridge expansion with or without reflection of the periosteum.

OBJECTIVE: To evaluate the role of the periosteum in preserving the buccal bone after ridge splitting and expansion with simultaneous implant placement. MATERIAL AND METHODS: In 12 miniature pigs, the mandibular premolars and first molars were removed together with the interdental bone septa and the buccal bone. Three months later, ridge splitting and expansion of the buccal plate was performed with simultaneous placement of two titanium implants per quadrant. Access by a mucosal flap (MF) was prepared on test sides, while a mucoperiosteal flap (MPF) with complete denudation of the buccal bone was increased on control sides. After healing periods of six and 12 weeks, the animals were sacrificed for histologic and histometric evaluation. RESULTS: In the MF group, all 16 implants were osseointegrated, while in the MPF group, four of 16 implants were lost. Noticeable differences of bone levels on the implant surface and of the bone crest (BC) were found between the MF and the MPF group. Buccally after 6 weeks, the median distance between the implant shoulder (IS) and the coronal-most bone on the implant (cBIC) was for the MF group -1.42 ± 0.42 mm and for the MPF group -4.80 ± 2.72 mm (P = 0.15). The median distance between the IS and the buccal BC was -1.24 ± 0.51 mm and -2.78 ± 1.98 mm (P = 0.12) for the MF and MPF group, respectively. After 12 weeks, median IS-cBIC was -2.12 ± 0.84 mm for MF and -7.19 mm for MPF, while IS-BC was -2.08 ± 0.79 mm for MF and -5.96 mm for MPF. After 6 weeks, the median buccal bone thickness for MF and MPF was 0.01 and 0 mm (P < 0.001) at IS, 1.48 ± 0.97 mm and 0 ± 0.77 mm (P = 0.07) at 2 mm apical to IS, and 2.12 ± 1.19 mm and 1.72 ± 01.50 mm (P = 0.86) at 4 mm apical to IS, respectively. After 12 weeks, buccal bone thickness in the MF group was 0 mm at IS, 0.21 mm at 2 mm apical to IS, and 2.56 mm at 4 mm apical to IS, whereas complete loss of buccal bone was measured from IS to 4 mm apical to IS for the MPF group. CONCLUSIONS: In this ridge expansion model in miniature pigs, buccal bone volume was significantly better preserved when the periosteum remained attached to the bone.

The bone splitting stabilisation technique--a modified approach to prevent bone resorption of the buccal wall.

The aim of this case series was to clinically demonstrate successful prevention of bone resorption of the buccal wall after alveolar bone splitting by additional stabilization of the lateral bone plate using a biphasic ceramic bone substitute. In three patients alveolar bone splitting was performed with a piezoelectric device. Clinical as well as radiological results after two and five years revealed stable hard and soft tissue conditions with no soft tissue recessions and peri-implant bone loss in three patients. The advantage of this one-stage procedure was the ability to insert dental implants into a very compromised bony site in a simultaneous procedure. Yet the bone splitting stabilisation technique appeared to be a more user-sensitive method.

Evaluation of a new experimental model to study bone healing after ridge expansion with simultaneous implant placement--a pilot study in minipigs.

OBJECTIVE: To evaluate the suitability of a minipig model for the study of bone healing and osseointegration of dental implants following bone splitting and expansion of narrow ridges. MATERIAL AND METHODS: In four minipigs, the mandibular premolars and first molars were extracted together with removal of the buccal bone plate. Three months later, ridge splitting and expansion was performed with simultaneous placement of three titanium implants per quadrant. On one side of the mandible, the expanded bone gap between the implants was filled with an alloplastic biphasic calcium phosphate (BCP) material, while the gap on the other side was left unfilled. A barrier membrane was placed in half of the quadrants. After a healing period of 6 weeks, the animals were sacrificed for histological evaluation. RESULTS: In all groups, no bone fractures occurred, no implants were lost, all 24 implants were osseointegrated, and the gap created by bone splitting was filled with new bone, irrespective of whether BCP or a barrier membrane was used. Slight exposure of five implants was observed, but did not lead to implant loss. The level of the most coronal bone-to-implant contact varied without being dependent on the use of BCP or a barrier membrane. In all groups, the BCP particles were not present deep in the bone-filled gap. However, BCP particles were seen at the crestal bone margin, where they were partly integrated in the new bone. CONCLUSIONS: This new minipig model holds great promise for studying experimental ridge splitting/expansion. However, efforts must be undertaken to reduce implant exposure and buccal bone resorption.

Digital method for quantification of circumferential periodontal bone level using cone beam CT.

OBJECTIVES: The objective of this study is to develop a new approach for radiographically measuring circumferential periodontal bone level using cone beam CT (CBCT) data. Accuracy and precision were assessed using direct probe measurements on a human skull as a reference. MATERIALS AND METHODS: Digital quantification of circumferential periodontal bone levels was conducted considering bone level measurements, infrabony crater, and furcation detection. For this purpose, a human bony cadaver skull with a restoration free dentition was used, showing periodontal bony defects of teeth 15-17,25-27,35-37,45-47 (FDI classification). Image datasets were acquired using a Promax 3D CBCT device (Planmeca Oy, Helsinki, Finland) at 80 kV and 8 mA, 160 µm voxel size. Circumferential radiographic measurements between cemento-enamel junction and the alveolar crest for the mesial, central, and distal bone levels on the oral and vestibular sides of the examined teeth were carried out based on a prototype of specifically developed software. The measurements were performed by an expert panel of three independent, calibrated, and blinded observers. Manual probe measurements of the periodontal bone loss served as reference standard. RESULTS: The adopted software allowed the quantification of periodontal bone loss at all examined teeth. Overall deviation between radiographic and manual measurements of the observers ranged between 0.36 and 0.69 mm; hereby, 83 % of all results were <0.5 mm. Comparing overall accuracy between the ten turns of radiological measurements, accuracy for all observers ranged from 0.29 to 0.46 mm. The present study design showed a 100 % detection of furcation involvement for radiographic evaluation. CONCLUSIONS: The adoption of a special measurement procedure in terms of a 3D coordinate system, which is placed through and perpendicular to the long axis of the tooth, allows consistent measurement positions of the mesial, central, and distal bone levels both for the oral and vestibular sides of the alveolar crest. In this way, reliable and reproducible quantification of circumferential periodontal bone loss using CBCT data with standardized resolution of 160 µm can be performed in all three dimensions. CLINICAL RELEVANCE: This new approach of radiographically assessing circumferential periodontal bone level using CBCT data shows a first promising attempt of accurate detection of periodontal bony defects. Yet, possible negative impact of further clinical parameters in terms of artifact occurrence will have to be furthermore carefully investigated.