The Poncho Lamina Technique: A Protocol for Hard and Soft Tissue Augmentation in Atrophic Ridges Receiving Adjacent Implants

The current scientific knowledge and guidelines in bone and soft tissue augmentation suggest the use of staged surgical workflows as the gold standard of regenerative procedures during implant therapy. In this context, the process is always the same, regardless of the techniques applied: an alternate series of surgical acts that follow one another after the completion of a specific period of osseointegration or graft maturation. As a result, the overall surgical treatment is often long and invasive and induces scar tissue formation. This article proposes a novel, fast, and less-invasive biphasic protocol with the use of a well-documented cortical barrier mounted on healing screws that are further replaced by customized abutments at an early second stage. Two cases are reported, one for an upper maxillary edentulous area and the other for a mandibular, with a total of four implants placed. The results at 4 months postop showed an optimal soft tissue configuration for both cases, with adequate cervical profile generation and a sufficient supracrestal complex height above the implant platforms. Significant bone gains were also recorded through CBCT data collection, either with alveolar width measurements on axial slices, the superposition of pre-op and post-op datasets, or 3D visualization after bone volume segmentation.

Immediate implant in the posterior region combined with alveolar ridge preservation and sealing socket abutment: A retrospective 3D radiographic analysis

BACKGROUND

Customized sealing socket abutment (SSA) has been claimed to optimize the peri-implant hard and soft tissues in type 1 implant placement. However, the evidence to claim the benefits of this technique over the use a conventional healing abutment remains weak.

PURPOSE

The aim of this retrospective study was to provide a 3D-radiographic evaluation of hard tissues changes following immediate implant placement in molar sites combined to ARP technique and installation of SSA.

MATERIALS AND METHODS

Baseline and follow-up (FU) CBCTs (from 1 to 5 years) of 26 patients were collected and included in the study. Baseline and FU CBCTs were superimposed and horizontal and vertical bone changes were assessed.

RESULTS

A total of 26 patients and 27 implants were included. Horizontal bone remodeling was not significant in any of the measured areas except in the most cervical level, where a mean bone remodeling of 0.73 mm was found. Proximal and buccal vertical bone changes were not significant.

CONCLUSIONS

Within the limits of a retrospective study, dimensional alveolar ridge changes 1 to 5 years after immediate implant placement in molar sites with simultaneous ARP technique and installation of SSA seem to be very limited.

Buccal bone regeneration combined with piezocision in adult orthodontic patients: Clinical, 3D radiographic, and patient-reported outcomes

OBJECTIVE

Assess the clinical effects, 3D radiographic results and patient-reported outcome measures (PROMs) of buccal bone regeneration combined with piezocision.

METHODS

Ten patients presenting roots prominence with a thin buccal bone thickness or buccal bone dehiscence in the lower front region were enrolled. Patients received orthodontic treatment assisted by piezocison which was combined with a buccal alveolar bone regeneration using a tunneling approach. A comparison between pre- and post-treatment alveolar bone measurements based on CBCT was performed. Periodontal parameters such as recession scores and root resorption were recorded before and after treatment. The PROMs were also investigated.

RESULTS

An overall significant buccal bone gain of 2.7 ± 2.7% was found after the treatment. The apical region reached the highest gain of 8.9 ± 5.5% whereas the most coronal region showed no significant increase of the bone envelope (1.2 ± 2.7%). No adverse event such as the appearance of recession or root resorption were observed. However, in 2 patients, the biomaterial was not properly integrated and seemed to be encapsulated. The pain level and the paracetamol consumption were equivalent to those after the placement of the orthodontic appliance except on the day of the surgery.

CONCLUSIONS

Within the limitation of this study, piezocision combined with buccal bone regeneration using a tunneling technique seems to be effective to augment bone and did not lead to gingival recession. However, in 2 cases the biomaterial seemed encapsulated, and therefore the predictability of the integration of the material can be questioned. ClinicalTrials.gov registration : NCT03655938.

Alveolar ridge dimensional changes after two socket sealing techniques. A pilot randomized clinical trial

OBJECTIVES

This pilot study aimed to assess dimensional changes following two different alveolar socket sealing techniques.

MATERIAL AND METHODS

Twenty-one patients requiring tooth extraction and implant placement were randomly allocated to two different alveolar ridge preservation techniques. In the control group, demineralized bovine bone mineral (DBBM) and a gingival soft tissue punch were used to fill and seal the socket, whereas in the test group, the extraction socket was filled with DBBM and sealed with a hemostatic gelatin sponge. Digitalized impressions were taken before and 6 months after tooth extraction. The comparison was made on horizontal and vertical dimensional changes.

RESULTS

The mean vertical loss was 0.8 ± 0.6 mm for the control group and 0.7 ± 0.5 mm for the test one. No statistical difference was found between groups for the vertical shrinkage. The horizontal dimensional narrowing of the alveolar socket was respectively 7.1/4.0/2.5 mm at levels 1, 3, and 5 mm from a coronal reference level for the control group. The test group showed dimensional changes of 4.8/2.3/1.3 mm at the three different levels, respectively. A significant difference was found at levels 3 and 5 mm. Referring to a visual analog pain scale, patients reported more severe pain in the control group (5.7/10) when compared with the test group (2.8/10). The difference was statistically highly significant (P ≤ 0.001).

CONCLUSIONS

A significant difference was found between control and test groups regarding the horizontal dimensional changes and the post-operative pain.

CLINICAL RELEVANCE

Regarding this primary result, the socket sealing technique with a hemostatic sponge provides an effective and inexpensive protocol with less post-operative pain.

The crucial role of imaging in digital dentistry

One of the recent trends in dentistry - and this in every field from the restorative to the orthodontic one- is the introduction of simplified completely digital workflows. Digital dentistry is supposed to allow dentists to work more efficiently, and this at higher precision, and with the possibility of all-in-one sessions using in-house computerized techniques. In this workflow, one of the major tools for simulating and transferring dental treatments is imaging. Both 3D low dose radiographic as well as optical imaging are playing crucial roles and have been overwhelming the market. Novel design platforms, compact and extremely fast milling and printing units are now also plentiful and rapidly being adopted in practice. Nevertheless, many of the steps in this digital dentistry process, no matter how simplified, present risks that can contribute to reduced precision and clinical difficulties. It is therefore the purpose of the article to briefly describe the role of imaging in this digital workflow, and where the pitfalls can be found that may lead to errors and imprecision.

Patient Eligibility for Standardized Treatment of the Edentulous Mandible: A Retrospective CBCT-Based Assessment of Mandibular Morphology

The aim of the study was to evaluate the proportion of patients recommended for full-arch mandibular restoration that would be eligible for treatment with a recently developed premanufactured full-arch prosthesis (Trefoil™, Nobel Biocare) based on the morphology of their lower jaw. Anonymized cone beam computed tomography (CBCT) data from 100 partially and fully edentulous patients referred for full-arch mandibular restoration were retrospectively collected from an imaging center database. Using custom-built software, CBCTs of mandibles were registered to a reference CBCT of a patient treated previously with a premanufactured full-arch prosthesis to determine if patients had adequate horizontal width and vertical height for implant placement. Bone height and thickness around simulated implants and distances to the incisive canal were evaluated. Mandibular arch width and semi-automated volume calculations were also performed. Using the system-specific 5.0 mm diameter implants with lengths of 13 and 11.5 mm, 85% and 86% of patients, respectively, were eligible for treatment with the standardized prosthesis. Eligibility was higher for men than women (odds ratio = 3.9, p = 0.045) due to increased bone volume. Based on mandibular morphology, our results suggest that the standardized treatment concept could serve a large percentage of patients with edentulous mandibles or failing dentition in the mandible.

Selective piezocision-assisted orthodontic treatment combined with minimally invasive alveolar bone regeneration: A proof-of-concept

BACKGROUND

Piezocision is a localised piezoelectric alveolar decortication involving minimally invasive corticotomies to accelerate orthodontic treatments. The objective of this proof-of-concept was to describe an innovative protocol combining selective piezocision with minimally invasive bone regeneration to reduce the risk of buccal tissue dehiscences often observed in orthodontic treatments. This proof-of-concept initial report aimed at investigating whether this new surgical concept is relevant.

MATERIALS AND METHODS

A patient presenting an asymmetrical dental class II, overcrowdings, midline deviations and buccal bone dehiscences in the lower incisor region was treated with this new treatment approach.

RESULTS

From an orthodontic point of view, the dental class II, the overcrowdings and the midlines were completely corrected. From a periodontal perspective, no gingival recession was observed; however, scars related to the piezocision were slightly visible at the mandible. The post-imaging demonstrated the absence of bone dehiscences. Up to 3 years after the completion of the treatment, no relapse was observed.

CONCLUSION

This novel approach suggested several advantages and may be further investigated at a larger scale in order to validate the benefits and to define the scope of intervention.

Comparison of micro-CT and cone beam CT on the feasibility of assessing trabecular structures in mandibular condyle

OBJECTIVES

To evaluate the accuracy of CBCT in assessing trabecular structures.

METHODS

Two human mandibles were scanned by micro-CT (Skyscan 1173 high-energy spiral scan micro-CT; Skyscan NV, Kontich, Belgium) and CBCT (3D Accuitomo 170; Morita, Japan). The CBCT images were reconstructed with 0.5 and 1 mm thicknesses. The condylar images were selected for registration. A parallel algorithm for histogram computation was introduced to perform the registration. A mutual information (MI) value was used to evaluate the match between the images obtained from micro-CT and CBCT.

RESULTS

In comparison with the micro-CT image for the two samples, the CBCT image with 0.5 mm thickness has a MI value of 0.873 and 0.903 while that with 1.0 mm thickness has a MI value of 0.741 and 0.752. The CBCT images with 0.5 mm thickness were better matched with micro-CT images.

CONCLUSIONS

CBCT shows comparable accuracy with high-resolution micro-CT in assessing trabecular structures. CBCT can be a feasible tool to evaluate osseous changes of jaw bones.

Dental wear estimation using a digital intra-oral optical scanner and an automated 3D computer vision method

The objective of this work was to propose an automated and direct process to grade tooth wear intra-orally. Eight extracted teeth were etched with acid for different times to produce wear and scanned with an intra-oral optical scanner. Computer vision algorithms were used for alignment and comparison among models. Wear volume was estimated and visual scoring was achieved to determine reliability. Results demonstrated that it is possible to directly detect submillimeter differences in teeth surfaces with an automated method with results similar to those obtained by direct visual inspection. The investigated method proved to be reliable for comparison of measurements over time.

Digital versus conventional implant impressions for edentulous patients: accuracy outcomes

PURPOSE

To compare the accuracy of digital and conventional impression techniques for completely edentulous patients and to determine the effect of different variables on the accuracy outcomes.

MATERIALS AND METHODS

A stone cast of an edentulous mandible with five implants was fabricated to serve as master cast (control) for both implant- and abutment-level impressions. Digital impressions (n = 10) were taken with an intraoral optical scanner (TRIOS, 3shape, Denmark) after connecting polymer scan bodies. For the conventional polyether impressions of the master cast, a splinted and a non-splinted technique were used for implant-level and abutment-level impressions (4 cast groups, n = 10 each). Master casts and conventional impression casts were digitized with an extraoral high-resolution scanner (IScan D103i, Imetric, Courgenay, Switzerland) to obtain digital volumes. Standard tessellation language (STL) datasets from the five groups of digital and conventional impressions were superimposed with the STL dataset from the master cast to assess the 3D (global) deviations. To compare the master cast with digital and conventional impressions at the implant level, analysis of variance (ANOVA) and Scheffe's post hoc test was used, while Wilcoxon's rank-sum test was used for testing the difference between abutment-level conventional impressions.

RESULTS

Significant 3D deviations (P < 0.001) were found between Group II (non-splinted, implant level) and control. No significant differences were found between Groups I (splinted, implant level), III (digital, implant level), IV (splinted, abutment level), and V (non-splinted, abutment level) compared with the control. Implant angulation up to 15° did not affect the 3D accuracy of implant impressions (P > 0.001).

CONCLUSION

Digital implant impressions are as accurate as conventional implant impressions. The splinted, implant-level impression technique is more accurate than the non-splinted one for completely edentulous patients, whereas there was no difference in the accuracy at the abutment level. The implant angulation up to 15° did not affect the accuracy of implant impressions.

Segmentation of Trabecular Jaw Bone on Cone Beam CT Datasets

BACKGROUND

The term bone quality is often used in a dentomaxillofacial context, for example in implant planning, as bone density and bone structure have been linked to primary implant success.

PURPOSE

This research aimed to investigate the performance of adaptive thresholding of trabecular bone in cone beam CT (CBCT) images. The segmentation quality was assessed for different imaging devices and upper and lower jaws.

MATERIALS AND METHODS

Four jaws were scanned with eight CBCT scanners and one micro-CT device. Images of the jaws were spatially aligned with the micro-CT images. Two volumes of interest for each jaw were manually delineated. Trabecular bone in the volumes of interest in the micro-CT images was segmented so that the micro-CT images could serve as high-resolution ground truth images. The volumes of interest in the CBCT images were segmented using both global and adaptive thresholding.

RESULTS

Segmentation was significantly better for the lower jaw than for the upper jaw. Differences in performance between the scanners were significant for both jaws. Adaptive thresholding performed significantly better in segmenting the bone structure out of CBCT images.

CONCLUSIONS

When assessing jaw bone structure, the observer should always choose adaptive thresholding. It remains a challenge to identify the optimal threshold selection for the structural assessment of jaw bone.

The influence of exposure parameters on jawbone model accuracy using cone beam CT and multislice CT

OBJECTIVE

The main purpose of this study was to investigate the influence of exposure parameters on jawbone model accuracy when using cone beam CT (CBCT) and multislice CT (MSCT).

METHODS

A lower and an upper edentulous human cadaver jaw were scanned using micro-CT (Skyscan 1173 high energy spiral scan micro-CT; Skyscan NV, Kontich, Belgium) at 35 μm to serve as true reference. The in vitro samples were exposed using six CBCT units and one MSCT system. CBCT exposure protocols were chosen according to clinically available settings. The variables were kilovoltage, milliamperage, voxel size and/or scan time. Image segmentation was based on local thresholds using profile lines. The resulting jawbone segmentations were registered with the reference and image processing was done to internally fill the segmentations. A point-based distance calculation was performed between the three-dimensional objects and reference scans and deviation percentages were calculated for 2 mm, 1 mm and 0.5 mm intervals.

RESULTS

All points of the MSCT surface models lay within a 1 mm deviation range and 98.5% within 0.5 mm compared with micro-CT. For the different CBCT systems, accuracy came close to MSCT with mean percentages of 98.9% within 1 mm deviation and 92.8% within 0.5 mm. A difference of approximately 1% between lower and upper jaws could be perceived. For the specific CBCT exposure protocols, only scan time and voxel size revealed certain significant differences.

CONCLUSION

Jawbone model accuracy using CBCT was comparable with MSCT. The surface models of the upper jaws deviated slightly more than those for lower jaws. CBCT exposure settings had a limited influence on accuracy with scan time and voxel size as the main factors.

The influence of tube potential on periodontal bone level measurements and subjective image quality using a digital photostimulable storage phosphor sensor

Objectives

The purpose of the present study was to determine the measurement accuracy and subjective image quality for periodontal disease diagnosis when using two X-ray tube voltages with a digital photostimulable storage phosphor sensor.

Material and Methods

A digital photostimulable storage phosphor (PSP) sensor (Vistascan) and a multipulse X-ray generator (Prostyle Intra) with two tube voltages were used in this study. The front, premolar and molar region of two adult human cadaver skulls jaws were imaged using the X-ray tube at 63 kV and 70 kV, both at 8 mA and decreasing exposure times (160 ms, 120 ms and 80 ms). A standardized exposure protocol containing waxed occlusal keys and an aiming device ensured proper and reproducible beam alignment. Three observers assessed the digital radiographs for 31 selected periodontal bone loss sites. Radiographic measurements were compared to physical measurements (Standard). Subjective ratings of lamina dura, crater defect and furcation involvement visibility, contrast perception and bone quality were also performed.

Results

Multiple regression equation of the variables kV and exposure time demonstrated no significant difference for the periodontal bone level measurements (P > 0.05). In 90.3% and 96.7% of the measurements for 70 kV and 63 kV respectively, deviation was within 1 mm. The subjective ratings produced similar findings in terms of image quality for both tube voltages and the three exposure times.

Conclusions

The results of the present study revealed that tube voltages of 63 kV and 70 kV provided similar accuracy and image quality for periodontal disease diagnosis.

The use of high-resolution digital imaging technology for small diameter K-file length determination in endodontics

To assess the reliability of high resolution intra-oral photostimulable storage phosphor (PSP) and complementary metal-oxide semiconductor (CMOS) imaging systems for working length (WL) assessment of small K-files in narrow and curved root canals. Eleven narrow and curved canals from extracted molars were used as pre-test for sample-size calculation. Nineteen canals from four cadavers were used for endodontic length assessment in the final study. Small K-files (ISO size 6, 8, and 10) were introduced into the canals at prepared length. Digital intra-oral radiographs were obtained using high-resolution Vistascan PSP plates and Sigma M CMOS active pixel sensor with a DC X-ray tube at 70 kV, 7 mA, and 0.16 s. Both image series were assessed with and without use of a dedicated endodontic filter. Three observers measured WLs for comparison to the gold standards of a digital millimeter ruler. Multiple regression analysis of the dependent measurements revealed no significant influence of imaging sensor (PSP or CMOS, p = 0.34) and image processing (p = 0.97). For ISO file size, however, there was a significant difference (p = 0.08) at a level of 10%. Observers mostly underestimated lengths using PSP but overestimated them on CMOS. Almost all radiographic measurements (96-98%) were within 2-mm deviation, while 71% to 82% deviated within 1 mm. Dedicated filtering and sensor type did not influence the outcome of WL determination of small file sizes when using high-resolution imaging sensors. WL determination with ISO file 6 did show a significant difference compared to ISO 8 and 10 but mostly for deviations <1.5 mm.

Detection of periodontal bone loss using digital intraoral and cone beam computed tomography images: an in vitro assessment of bony and/or infrabony defects

OBJECTIVES

To explore the diagnostic values of digital intraoral radiography and cone beam CT (CBCT) in the determination of periodontal bone loss, infrabony craters and furcation involvements.

METHODS

Accuracy assessment of the imaging modalities was conducted through bone level measurements, infrabony crater and furcation involvement classifications. For CBCT, images were obtained at 120 kV and 23.87 mAs, and observations were made on a 5.2 mm panoramic reconstruction view and on 0.4 mm thick cross-sectional slices. Intraoral radiographs of a size 2 charge-coupled device (CCD) sensor were obtained using the paralleling technique, at 60 kV (DC) and 0.28 mAs exposure. 71 human cadaver and dry skull bony defects were measured and evaluated by 3 observers. Comparison was made with the gold standard.

RESULTS

The mean error (gold standard deviation) of bone level measurements was 0.56 mm for intraoral radiography and 0.47 mm for the CBCT panoramic 5.2 mm reconstruction view. There were no significant differences (P = 0.165) between the two methods. However, on 0.4 mm thick cross-sections, the mean error was 0.29 mm and the Wilcoxon signed-rank test indicated a significant difference when compared with the CCD (P = 0.006). The detection of crater and furcation involvements failed in 29% and 44% for the CCD, respectively, in contrast to 100% detectability for both defects with CBCT.

CONCLUSIONS

CBCT on the panoramic 5.2 mm reconstruction view allowed comparable measurements of periodontal bone levels and defects as with intraoral radiography. CBCT with 0.4 mm thick cross-sections demonstrated values closer to the gold standard, indicating more accurate assessment of periodontal bone loss. Further research is needed to explore these results in vivo and to determine the use of CBCT in periodontal diagnosis.

Diagnostic validity (or acuity) of 2D CCD versus 3D CBCT-images for assessing periodontal breakdown

OBJECTIVE

The objective of this study was to compare 2-dimensional intraoral digital images with 3-dimensional cone beam CT (CBCT) in assessment of periodontal bone levels and defects.

METHODS

Thirty periodontal bone defects of 2 adult human skulls (with soft tissue or substitute) were evaluated by using intraoral digital radiography and CBCT. Digital radiographs were made with a size #2 CCD sensor and a 60-kV DC x-ray unit, with 0.28, 0.42, or 0.56 mAs as respective exposure settings. For CBCT, jawbone images were obtained at 120 kV and 23.87 mAs. Periodontal bone levels and defects on both imaging modalities were assessed and compared to the gold standard. Delineation of lamina dura, crater defect, furcation involvements, contrast, and bone quality were also analyzed.

RESULTS

Linear measurement deviations of periodontal bone levels from the gold standard ranged from 0.19 to 1.66 mm for intraoral radiography versus 0.13 to 1.67 mm for CBCT. Accuracy was not significantly different between both imaging modalities (P = .161). Intraoral radiography scored significantly better for contrast, bone quality, and delineation of lamina dura, but CBCT was superior for assessing crater defects and furcation involvements (P = .018).

CONCLUSIONS

CBCT images allowed comparable measurements of periodontal bone levels and defects as intraoral radiography. CBCT images demonstrated more potential in the morphological description of periodontal bone defects, while the digital radiography provided more bone details. These findings may offer perspectives for further studies on periodontal diagnostics, prognostics, and presurgical planning with CBCT.