Evaluation of peri-implant buccal bone by computed tomography: an experimental study

Fatigue lifetime of reduced-diameter implants placed in different bone models

OBJECTIVES

This study assessed the fatigue lifetime of reduced-diameter implants placed in either bovine rib or polymer-based bone model.

METHODS

Bovine ribs were classified according to the criteria proposed by Lekholm and Zarb and were analyzed for bone fraction. Fourteen dental implants (3.25 mm in diameter × 15 mm in length) were placed in bovine ribs used as a bone model. They were subjected to resonance frequency analysis. Stainless steel loading hemisphere caps were bonded on the abutments position at 30-degree angle and with a moment arm of 11 mm. Accelerated life testing using the step-stress method was conducted at 2 Hz with a stress ratio of 0.1 until fracture on a servo-hydraulic load frames machine (MTS). Results were compared with those of a previous study wherein implants were placed in a polymer-based bone model. Fatigue lifetime statistics (characteristic lifetime and Weibull modulus) of physical specimens were estimated in a reliability analysis software (ALTA PRO). Fractured specimens were examined under an electron scanning microscope to determine the failure mode.

RESULT

The implants exhibited high stability quotient values (75.07 ± 3.81). Implants placed in bovine ribs showed better data dispersion and longer fatigue lifetime than those placed in polymer-based bone models, with no significant difference between groups. All fractures occurred in the implant body near the bone level and were indicative of fatigue fractures.

SIGNIFICANCE

Bovine ribs appear to be a more suitable material for accelerated life testing than the polymer-based material because of better data dispersion.

Diagnostic methods/parameters to monitor peri-implant conditions

The diagnostic accuracy of clinical parameters, including visual inspection and probing to monitor peri-implant conditions, has been regarded with skepticism. Scientific evidence pointed out that primary diagnostic tools (chairside) seem to be highly specific, while their sensitivity is lower compared with their use in monitoring periodontal stability. Nonetheless, given the association between pocket depth at teeth and implant sites and the aerobic/anaerobic nature of the microbiome, it seems plausible for pocket probing depth to be indicative of disease progression or tissue stability. In addition, understanding the inflammatory nature of peri-implant diseases, it seems reasonable to advocate that bleeding, erythema, ulceration, and suppuration might be reliable indicators of pathology. Nevertheless, single spots of bleeding on probing may not reflect peri-implant disease, since implants are prone to exhibit bleeding related to probing force. On the other side, bleeding in smokers lacks sensitivity owing to the decreased angiogenic activity. Hence, the use of dichotomous scales on bleeding in the general population, in contrast to indices that feature profuseness and time after probing, might lead to false positive diagnoses. The definitive distinction between peri-implant mucositis and peri-implantitis, though, relies upon the radiographic evidence of progressive bone loss that can be assessed by means of two- and three-dimensional methods. Accordingly, the objective of this review is to evaluate the existing clinical and radiographic parameters/methods to monitor peri-implant conditions.

Evaluation of buccal bone resorption in immediate implant placement in thin versus thick buccal bone plates: An 18-month follow-up prospective cohort study

OBJECTIVES

The current guidelines recommend that immediate implants be placed in patients with thick (>1 mm) buccal bone due to the inevitable tissue remodeling that follows tooth extraction. The aim of the current study was to investigate the effect of buccal bone thickness on bone resorption in immediate implant placement and compare two measuring techniques of the aforementioned resorption.

MATERIALS

The present study was designed as a prospective nonrandomized, controlled clinical trial. A total of 30 implants were split between the two study arms, thin buccal bone and thick buccal bone. The primary outcome was to assess vertical bone changes radiographically by cone beam scans preoperatively, at 2 months and 18 months after implant placement in patients with thin and thick buccal plate. Secondary outcomes included the change in the thickness of the buccal bony plate, marginal bone loss, and pink esthetic score.

RESULTS

Only 26 implants were statistically analyzed as one early failure was observed in each group. Furthermore, 2 patients of the thick group withdrew from the study. Cone beam computed tomography measurements revealed that at 2 months the vertical bone loss was 1.09 for the thin group and 0.85 for the thick group. The buccal bone plate resorption of the thin group was 0.39 mm while it was 0.52 mm for the thick group. The buccal bone plate was 1.25 mm in the thin group and 1.88 mm in the thick group. The PES did not show any significant difference with very good esthetic results.

CONCLUSION

Within the limitations of the current study, the amount of buccal bone plate resorption and the subsequent thickness obtained after implantation in both groups suggest successful long-term results. The two measuring techniques have proven to be comparable and reliable in the measurement of buccal bony plate changes. https://classic.

CLINICALTRIALS

gov/ct2/results?cond=&term=NCT04731545&cntry=EG&state=&city=&dist=.

Classification of the implant-ridge relationship utilizing the MobileNet architecture

Background/purpose

Proper implant-ridge classification is crucial for developing a dental implant treatment plan. This study aimed to verify the ability of MobileNet, an advanced deep learning model characterized by a lightweight architecture that allows for efficient model deployment on resource-constrained devices, to identify the implant-ridge relationship.

Materials and methods

A total of 630 cone-beam computerized tomography (CBCT) slices from 412 patients were collected and manually classified according to Terheyden's definition, preprocessed, and fed to MobileNet for training under the conditions of limited datasets (219 slices, condition A) and full datasets (630 cases) without and with automatic gap filling (conditions B and C).

Results

The overall model accuracy was 84.00% in condition A and 95.28% in conditions B and C. In condition C, the accuracy rates ranged from 94.00 to 99.21%, with F1 scores of 89.36-100.00%, and errors due to unidentifiable bone-implant contact and miscellaneous reasons were eliminated.

Conclusion

The MobileNet architecture was able to identify the implant-ridge classification on CBCT slices and can assist clinicians in establishing a reliable preoperative diagnosis and treatment plan for dental implants. These results also suggest that artificial intelligence-assisted implant-ridge classification can be performed in the setting of general dental practice.

The feasibility of ultrasonography for the measurement of periodontal and peri-implant phenotype: A systematic review and meta-analysis

BACKGROUND

Screening ultrasonography was proposed for monitoring periodontal soft tissues in the early 1960s, owing to its nonionizing, real-time, and cost-effective properties. Studies have provided convincing preliminary evidence for the use of ultrasound (US) in implant dentistry.

PURPOSE

To assess the feasibility of ultrasonography (US) for measuring the buccal thickness of periodontal and peri-implant tissues. The secondary objective was to evaluate the reliability of US measurements compared to classic techniques, such as CBCT and directly measurements.

MATERIALS AND METHODS

An electronic literature search was conducted by three independent reviewers through February 2023. The inclusion criteria were articles investigating at least five patients/cadavers with US measurements in periodontal or peri-implant buccal tissues. Compliance with methodological reporting standards and risk of bias was assessed using EULAR and QUADAS-C tools, respectively. Random-effects meta-analysis was conducted, using Bland-Altman analysis. Certainty of the evidence was assessed using GRADE.

RESULTS

The final selection included 12 studies examining 458 patients and 13 cadavers, with a total of 226 implants, 1958 teeth and 60 edentulous sites. The body of evidence was assessed as partially compliant with methodological reporting standards for US studies and had an unclear to high risk of bias. Meta-analysis of five comparative studies showed no evidence of clinically significant bias between US and direct measurements (very low certainty), and between US and CBCT (very low certainty) for soft-tissue thickness. Likewise, for bone thickness, there is no evidence of clinically significant bias between US and CBCT (low certainty).

CONCLUSIONS

Compared to the CBCT and direct measurements, ultrasonography might be a reliable approach for monitoring on periodontal and peri-implant phenotype. However, there is uncertainty about estimates of the actual effect, so further standardized and larger sample size of clinical research is needed.

Extraction of high inverted mesiodentes via the labial, palatal and subperiostal intranasal approach：A clinical prospective study

The aim of this study is to provide criteria for the choice of the surgical approach for extraction of high inverted mesiodens. The operation statistics, life quality of postoperative patients, and the operative injury/recovery were compared and analysed. The laser Doppler blood flowmetry, laser speckle contrast imaging, and electric pulp testing were explored to detect the postoperative pulp and gingiva blood supply of adjacent teeth. For the clinician's primary concerns, the surgical time, the volume of osteotomy, and the amount of bleeding in the labial approach group (The p values are 0.0001, <0.0001, and 0.0131, respectively.) and intranasal approach group (All p values were <0.0001.) were significantly less than that in the palatal approach group. However, from the patient's perspective, the postoperative swelling in the labial approach was far more than that in the intranasal approach group (p =0.0044), with unsurprisingly lower satisfaction (p <0.0001). There were no significant differences in pulp and gingival blood supply of adjacent teeth and jaw development. Trauma was manageable in all patients. Within the limitations of the study it seems that extraction of mesiodens by the intranasal approach achieves a delicate balance between reducing surgical trauma and optimizing postoperative recovery.

Analysis of peri-implant bone defects by using cone beam computed tomography (CBCT): an integrative review

The objective of this work was to perform an integrative review of the inspection of peri-implant bone defects using cone beam computed tomography (CBCT). An electronic search was performed in the PubMed database using the following scientific terms: CBCT or Cone Beam computed tomography; dental implant; peri-implant; bone loss; defects. The survey identified 267 studies, of which 18 were considered relevant to this study. These studies provided important data taking into account the accuracy of cone beam computed tomography in the detection and measurement of peri-implant bone defects such as fenestrations, dehiscence and intraosseous circumferential defects. The effectiveness of CBCT in aiding in geometric bone calculations and in the diagnosis of peri-implant defects was influenced by factors such as artefacts, defect size, bone wall thickness, implant material, adjustment of acquisition parameters and observer experience. A not insignificant number of studies compared intraoral radiography to CBCT in the detection of peri-implant bone loss. CBCT was clearly superior to intraoral radiography in the detection of all peri-implant bone defects, except for defects located in the interproximal zone. In general, studies have shown that peri-implant bone measurements adjacent to the implant surface can be correctly determined, as well as the diagnosis of peri-implant bone defects with an average discrepancy of less than 1 mm from the actual measurement of the defect.

Influence of Exposure Parameters and Implant Position in Peri-Implant Bone Assessment in CBCT Images: An In Vitro Study

The aim of this study was to assess the impact of dimensional distortion and its changes with modification of exposure setting parameters on the measurements of peri-implant bone margin. Ten titanium dental implants (InKone Primo, Global D, Paris, France) were placed in two prepared bovine ribs. Two bone models and an implant-with-transfer model were scanned with 3shape E4 (3shape, Copenhagen, Denmark) laboratory scanner. Cone beam computed tomography (CBCT) images of two bone models were taken with different values of voltage (60, 70, 80, 90 kV), tube current (4, 10 mA) and voxel size (200, 300 µm). All the data were superimposed using planning software, and the measurements of buccal bone thickness in two selected regions were performed both using CBCT and scan cross-sections. The mean squared error (MSE) being the squared differences between measurements was used in the accuracy assessment of the CBCT device. A one-way ANOVA revealed significant differences between voltage and MSE (p = 0.044), as well as implant position and MSE (p = 0.005). The distortions of measurements depend on bone margin thickness, and the higher the distance to measure, the higher the error. Accurate measurements of buccal bone thickness (MSE below 0.25) were achieved with voltage values of 70, 80, and 90 kV.

The accuracy of probing, ultrasound and cone-beam CT scans for determining the buccal bone plate dimensions around oral implants - A systematic review

OBJECTIVE

The objective of this review was to assess the accuracy of available means of determining the BBT (buccal bone thickness) and/or BBL (buccal bone level). This was translated into the following research question: What is the accuracy of the available means of visualizing the BBP (buccal bone plate) to establish the BBT and/or the BBL, when compared to control measurements? As control measurements histomorphometric measurements, direct measurements and cone-beam computed tomography (CBCT) measurements in the absence of metal are accepted.

BACKGROUND DATA

METHODS: The literary search was performed by searching the databases of MEDLINE, Embase, and Web of Science, up to July 13, 2021. Types of studies included were clinical, in vitro and animal trials, specifically looking into the bone level and/or bone thickness of the buccal bone plate at oral implants. Reference lists were hand searched for relevant articles. Two reviewers performed the data extraction and analysis. Only studies using reliable control measurements to evaluate the accuracy of the tested means of visualizing BBT and/or BBL were included for analysis. The QUADAS-2 tool was used to perform bias analysis on the relevant studies. Extracted data was tabulated to show the differences between test and control measurements for BBT and BBL. For in vitro studies on CBCT measurements of BBT meta-analysis could be performed.

RESULTS

A total of 1176 papers were identified in the search. Twenty-two articles were used for data extraction and qualitative analysis. Of these studies nine were animal studies, 9 were in vitro studies and four were human studies. Six animal studies and three human studies provided data on probing. CBCT and sonography as techniques for visualizing the buccal bone plate. Probing at implant sites seems to provide data that correlates with a consistent distance from the BBP. Meta-analysis for probing studies could not be performed due to heterogeneity in the setups of these studies. Eleven studies on CBCT were eligible for inclusion. Of these three were animal studies, the remaining 8 studies were all in vitro studies. Meta-analysis was performed on the accuracy of CBCT for in vitro studies, finding a significant underestimation of the BBT when compared to control measurements by a mean difference of -0.15 mm with 95%CI [-0.26,-0.03]. Three studies were identified on measurement of BBT and/or BBL by sonography. This included one human study and two in vitro studies. The identified studies show a low error when determining the buccal bone level or thickness using sonography. All included studies possess a high risk of bias according to risk of bias analysis, mostly due to selection of the patient.

CONCLUSION

A strong limitation of this systematic review is the inclusion of different studies with heterogeneous designs. Within the limits of this analysis it cannot be concluded that probing is an accurate way of visualizing the BBP. CBCT cannot yet be recommended as a standard diagnostic tool for follow-up of the BBP at oral implants. The application of sonography as a diagnostic tool to visualize the BBP needs further scientific validation.

Assessment of the relationship between labial gingival thickness and the underlying bone thickness in maxillary anterior teeth by two digital techniques

This study aimed to noninvasively assess the relationship between the labial gingival thickness (GT) and the underlying bone thickness (BT) of maxillary anterior teeth by two digital techniques. A total of 30 periodontally healthy participants with 172 maxillary anterior teeth were enrolled. GT and BT were measured at 2, 4 and 6 mm apical to the cemento-enamel junction (CEJ) by two digital techniques: M1—cone-beam computed tomography (CBCT) and M2—digital intraoral scanning (DIS) combined with CBCT. The Pearson's correlation coefficient was calculated to determine the correlation between GT and BT. A significant negative correlation was identified between GT and BT at 2 mm apical to the CEJ for central incisors (CI), lateral incisors (LI), and canines (CA) both by M1 and M2, while a weak negative correlation at 4 mm apical to the CEJ was observed by M1 for CA. No significant correlation was found at other sites by both M1 and M2. The labial BT was < 1 mm in most cases (85% of CI; 97% of LI; and 90% of CA). Within the limitation of this study, it was concluded that GT and BT seemed to be negatively correlated at 2 mm apical to the CEJ. Therefore, caution is warranted when implant restoration at the esthetic area of the anterior teeth.

Bone loss-related factors in tissue and bone level dental implants: a systematic review of clinical trials

Dental implants are popular for dental rehabilitation after tooth loss. The goal of this systematic review was to assess bone changes around bone-level and tissue-level implants and the possible causes. Electronic searches of PubMed, Google Scholar, Scopus, and Web of Science, and a hand search limited to English language clinical trials were performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines up to September 2020. Studies that stated the type of implants used, and that reported bone-level changes after insertion met the inclusion criteria. The risk of bias was also evaluated. A total of 38 studies were included. Eighteen studies only used bone-level implants, 10 utilized tissue-level designs and 10 observed bone-level changes in both types of implants. Based on bias assessments, evaluating the risk of bias was not applicable in most studies. There are vast differences in methodologies, follow-ups, and multifactorial characteristics of bone loss around implants, which makes direct comparison impossible. Therefore, further well-structured studies are needed.

Hard tissue dimensional changes following implant removal due to peri-implantitis: A retrospective study

BACKGROUND

The current evidence regarding the alterations experienced by the alveolar ridge (hard tissue changes) after implant removal due to peri-implantitis is limited.

PURPOSE

To assess the hard tissue dimensional changes following implant removal due to peri-implantitis.

MATERIAL AND METHODS

Clinical records were examined to identify patients with implants that had to be removed due to a hopeless prognosis secondary to peri-implantitis due to expendability of peri-implantitis implants for functional reasons. Patients with preoperative and postoperative cone-beam computed tomography (CBCT) scans were included. Patient-related, implant-related, and surgery-related factors were assessed based on the clinical records. Linear measurements were made to evaluate the influence of bone plate thickness (BPT), ridge width (RW), and ridge height (RH) at various levels upon the outcome of implant removal. A descriptive statistical analysis of the quantitative and qualitative variables was performed. Correlations of the variables with the primary outcome (dimensional changes) were tested using univariate and multivariate analyses (multinomial random intercept mixed model linear regressions).

RESULTS

A total of 26 patients (n_implants = 79) met the eligibility criteria. The mean decrease in RW at 1 and 3 mm below the crest was 11.3% and 4.4%, respectively (P < 0.001). Buccal and lingual RH was significantly reduced by 2.2% and 6.3%, respectively (P < 0.001). Few patient-related, implant-related, and surgery-related factors appeared to have an impact upon the hard tissue dimensional changes. Bone regeneration simultaneous to implant removal minimized the dimensional changes of the ridge both vertically (5% lesser buccal RH reduction) and horizontally (12% lesser RW reduction) when compared with spontaneous healing. The use of a reverse-torque removal kit seemed to be critical in limiting the dimensional changes of the ridge.

CONCLUSIONS

Minimal hard tissue changes can be expected following implant removal due to peri-implantitis. Simultaneous bone regeneration procedures and the use of a removal kit may considerably reduce the impact upon the dimensional changes (NCT04534361).

Height difference between the vestibular and palatal walls and palatal width: a cone beam computed tomography approach

Background

The objective of this study was to measure two parameters involved in tri-dimensional implant planning: the position of the buccal and palatal bone wall and the palatal thickness.

Methods

Cone beam computed tomography (CBCT) images (Planmeca ProMax 3D) of 403 teeth (208 upper teeth and 195 lower teeth) were obtained from 49 patients referred to the Dental School of Seville from January to December 2014. The height difference between the palatal and buccal walls was measured on the most coronal point of both walls. The thickness of the palatal wall was measured 2 mm from the most coronal point of the palatal wall.

Results

The mean values in the maxilla were 1.7 ± 0.9 mm for central and lateral incisors, 2.2 ± 1.7 mm for canines, 1.6 ± 0.9 mm for premolars and 1.9 ± 1.5 mm for molars. In the lower jaw, the mean values were 1.3 ± 0.8 mm for incisors, 1.7 ± 1.2 mm for canines, 2.3 ± 1.3 mm for premolars, and 2.6 ± 1.7 mm for molars. In the upper jaw, more than 55% of maxillary teeth (excluding second premolars and molars) presented mean height differences greater than 1 mm. In the mandible, more than 60% of incisors showed a buccal bone thickness of 1 mm from the apical to lingual aspect. All teeth except the second premolar presented a buccal wall located more than 1 mm more apically than the lingual bone wall.

Conclusions

The buccal bone wall is located more apically (greater than 1 mm) than the palatal or lingual table in most of the cases assessed. The thickness of the palatal or lingual table is also less than 2 mm in the maxilla and mandible, except in the upper canines and premolars and the lower molars.

The fence technique: Autogenous bone graft versus 50% deproteinized bovine bone matrix / 50% autogenous bone graft-A clinical double-blind randomized controlled trial

OBJECTIVES

The aim of this short-term double-blind, parallel, randomized clinical trial was to compare bone augmentation grafting with 100% autogenous bone (AB) or 50% deproteinized bovine bone matrix (DBBM)/ 50% autogenous bone (BOAB) using a guided bone regeneration procedure, the fence technique, in a two-stage implant placement.

MATERIAL AND METHODS

Partially edentulous patients with extensive three-dimensional osseous defects were included in this study. The main outcome measure was the differences in bone volume from pre-surgery (T1) to 6 months post-surgery (T2). Bone height, chair-time, pain, functional limitation, and complications were also assessed.

RESULTS

Fifteen patients were allocated to the AB group and 15 patients to the BOAB group. The difference in bone volume from T1 to T2 was 648 mm³ for the AB group and 869mm³ for the BOAB group (difference between groups 221 mm³ , 95% CI from -363 to 804, p = .442). The surgery pain VAS was 1.6 for the AB group and 2.3 for the BOAB group (difference between groups 0.8, 95% CI from 0.0 to 1.5, p = .045 favoring the AB group). The height difference in bone from T1 to T2 was 2.2 mm for the AB group and 3.7 mm for the BOAB group (difference between groups 1.5mm, 95% CI from 0.1 to 2.9, p = .038 favoring the BOAB group). For complications, chair-time, post-surgery pain, and functional limitation, there were no differences between AB and BOAB.

CONCLUSIONS

No significant differences, except for surgery pain VAS and difference in bone height, were observed in this trial comparing grafting with AB or BOAB.

Accuracy of cone-beam computed tomography is limited at implant sites with a thin buccal bone: A laboratory study

BACKGROUND

To evaluate whether buccal bone thickness (BBT), implant diameter, and abutment/crown material influence the accuracy of cone-beam computed tomography (CBCT) to determine the buccal bone level at titanium implants.

METHODS

Two implant beds (i.e., narrow and standard diameter) were prepared in each of 36 porcine bone blocks. The implant beds were positioned at a variable distance from the buccal bone surface; thus, resulting in three BBT groups (i.e., >0.5 to 1.0; >1.0 to 1.5; >1.5 to 2.0 mm). In half of the blocks, a buccal bone dehiscence of random extent ("depth") was created and implants were mounted with different abutment/crown material (i.e., titanium abutments with a metal-ceramic crown and zirconia abutments with an all-ceramic zirconia crown). The distance from the implant shoulder to the buccal bone crest was measured on cross-sectional CBCT images and compared with the direct measurements at the bone blocks.

RESULTS

While abutment/crown material and implant diameter had no effect on the detection accuracy of the buccal bone level at dental implants in CBCT scans, BBT had a significant effect. Specifically, when BBT was ≤1.0 mm, a dehiscence was often diagnosed although not present, that is, the sensitivity was high (95.8%), but the specificity (12.5%) and the detection accuracy (54.2%) were low. Further, the average measurement error of the distance from the implant shoulder to the buccal bone crest was 1.6 mm.

CONCLUSIONS

Based on the present laboratory study, BBT has a major impact on the correct diagnosis of the buccal bone level at dental titanium implants in CBCT images; in cases where the buccal bone is ≤1 mm thick, detection of the buccal bone level is largely inaccurate.

Factors associated with the presence of peri-implant buccal soft tissue dehiscences: A case-control study

BACKGROUND

To identify factors associated with the presence of buccal soft tissue dehiscences (BSTD).

METHODS

This cross-sectional observational study assessed 52 cases (CAS) with a minimum of 24 months of loading, with the presence of a BSTD, defined as an exposure of the prosthetic abutment, the implant neck or the implant surface in the anterior maxillae or mandible (premolar-premolar) and 52 carefully selected controls (CON) matched for age and years in function, being the only difference between groups the BSTD. Clinical parameters and radiographic findings from periapical radiographs and Cone Beam Computed Tomographies (CBCT) were analyzed to assess their association with the occurrence of BSTD using a multivariate regression model.

RESULTS

The CAS had a mean keratinzed mucosa (KM) of 1.65 ± 1.31 mm, whereas in the CON KM was 3.27 ± 1.28 mm (P = 0.001). Probing depths were similar in both groups, whereas bleeding on probing and plaque scores were higher in the CAS (P = 0.001). Mean bone level scores in the CAS were 1.71 ± 1.04 mm, and 1.27 ± 1.01 mm in CON (P = 0.143). The first bone to implant contact at the buccal aspect was 4.85 ± 3.12 mm in CAS and 2.15 ± 3.44 mm in CON (P = 0.001). CAS were 1.48 ± 0.93 mm outside the alveolar envelope, whereas the CON were 0.46 ± 0.77 mm. Implants buccally positioned in the CBCT's were 34 times more likely to belong to the case group. The presence of >2 mm of KM at the time of evaluation, presence of adjacent natural teeth, cemented restorations and two-piece implants were protective factors.

CONCLUSION

The bucco-palatal implant position was the most relevant factor related to the presence of BSTD.

Assessment of Peri-implant Buccal Bone Thickness Using Digital Imaging Techniques: A Systematic Review and Meta-analysis

Objectives:

This systematic review aimed to answer the following focused question: Do the currently available imaging techniques provide accuracy in the assessment of peri-implant buccal bone thickness?

Methods:

A search strategy was conducted in eight electronic databases, followed by an additional manual search in grey literature and references of selected articles. Studies evaluating the accuracy of imaging techniques to measure peri-implant buccal bone thickness were included. Individual risk of bias was assessed by the Quality Assessment Tool for Diagnostic Accuracy Studies-2 (QUADAS-2). Meta-analysis was performed to evaluate CBCT accuracy. The overall effect size was determined by means of the Z-test. Q test was used to evaluate the homogeneity of effect sizes among studies and I2 was applied to determine the variance within studies.

Results:

After an initial screening, 83 studies were further selected for full reading and 13 of them were considered eligible for this review. In sum, the accuracy of Cone-beam Computed Tomography (CBCT), of ultrasound, and of computed tomography were assessed. There was no statistically significant difference between CBCT and the gold standard (p=0.81). The mean difference between measurements of bone thickness obtained by CBCT and the goldstandard was -0.0.3mm [95%CI -0.29;0.253mm].

Conclusion:

CBCT showed acceptable accuracy for assessing peri-implant bone. No meaningful conclusion could be drawn about other techniques.

Long-term clinical and radiographic results after treatment or no treatment of small buccal bone dehiscences at posterior dental implants: A randomized, controlled clinical trial

AIM

To test whether or not buccal vertical bone dehiscences (≤5 mm) around posterior implants left for spontaneous healing (SH) result in the same clinical and radiologic outcome as dehiscences treated with guided bone regeneration (GBR) at 7.5 years after implant placement (IMPL).

MATERIALS AND METHODS

Twenty-two patients receiving 28 posterior implants with a small non-contained buccal bone dehiscence (≤5 mm) were randomly assigned to the SH or the GBR group. Implants were loaded at 6 months. Clinical parameters (probing depths, sulcus bleeding index, plaque index) and approximal marginal radiographic bone levels were assessed regularly up to at least 6.8 years. The vertical extension of the dehiscences was measured clinically at IMPL and abutment connection and radiographically on cone beam computed tomographys at a mean follow-up time of 7.5 years.

RESULTS

Twenty patients with a total of 26 implants were recalled at 7.5 years (9.1% dropout). The implant/crown survival rates were 100% in both groups. Stable peri-implant tissues were observed in both groups showing only minimal signs of inflammation. During the entire study period (IMPL-7.5-year follow-up), the median buccal vertical bone gain measured 1.61 mm for the GBR group and 0.62 for the SH group showing no significant difference between the groups. Also, at 7.5 years, the median approximal marginal bone levels (GBR: 0.53; SH: 0.68) were not significantly different between the two groups (p = .61) while the remaining median buccal vertical dehiscences were larger in the SH group (2.51 mm) compared to the GBR group (1.66 mm; p = .02).

CONCLUSIONS

Implants with small non-contained buccal bone dehiscences exhibited high implant survival rates and healthy peri-implant tissues at 7.5 years. In the GBR group, the buccal vertical bone levels were higher compared to the SH group but remained stable over the entire study period for both treatments.

Flapless immediate implant placement and provisionalization in periodontal patients: A retrospective consecutive case-series study of single-tooth sites with dehiscence-type osseous defects

OBJECTIVE

To assess the clinical outcomes of flapless, immediate implant placement with simultaneous augmentation of dehiscence defects and immediate provisional restoration.

MATERIALS AND METHODS

Retrospective evaluation of 40 periodontal patients who received a flapless immediate implant for single-tooth replacement with simultaneous augmentation of dehiscence defects and immediate provisional restoration, at follow-up periods ranging from 1 year minimum to 7 years maximum. Dehiscence defects were augmented using autogenous bone grafts and/or deproteinized bovine bone mineral, and autogenous or allogeneic connective tissue grafts. The following aspects were evaluated: clinical success (Clinical Oral Implants Research, 8, 1997, 161), crestal bone loss (calibrated digital periapical X-rays) and aesthetics (Pink Esthetic Score, PES). Additionally, a questionnaire was devised to obtain patient's subjective evaluation.

RESULTS

A 98.3% (95% CI: 91%-99%) success rate was observed. At 8 weeks, mean bone loss was 0.47 mm (n = 39); between 8 weeks and 1 year, this va lue attained 0.24 mm and between years 1 and 5 years 0.06 mm (n = 9). The evaluated PES in 37 single-tooth implants was 12.4, with PES = 7 (aesthetic failures) in two cases, and aesthetic outcomes were excellent (PES ≥ 12) in 29 cases (78.4%). When compared with the contralateral tooth, a recession under 1 mm was observed in 78% of cases. The patient's subjective satisfaction value ranged from 98% to 100%.

CONCLUSION

This type of minimally invasive treatment of alveoli with buccal plate deficiencies delivers, in the hands of an experienced clinician, a high clinical and aesthetic success percentage being rated by patients as satisfactory. Clinicians should be aware that 1-2 mm comparative recession could be observed.

High-Frequency Ultrasound for Assessment of Peri-Implant Bone Thickness

Purpose: The aim of this study was to evaluate the accuracy of high-frequency ultrasound (HFUS) for measurement of bone thickness surrounding dental implants. Methods: Eight porcine bone samples containing dental implants were scanned by a HFUS scanner and compared using cone-beam computed tomography (CBCT) and an optical scanner. Bone thickness was measured in the buccolingual region of dental implants in 10 points distributed between the platform and apical portion of the implant. Results: The mean measurement error for the ultrasound method was 0.11 mm, whereas CBCT showed a measurement error of 0.20 mm. For both devices, the maximal measurement error was 0.28 mm. Conclusion: Within the simulated limited conditions of this study, high-frequency ultrasound, with optical scanning used as a reference, presented higher accuracy in comparison to CBCT, and seems to be a promising tool for measuring peri-implant bone.

Therapeutic alternatives for addressing pink esthetic complications in single-tooth implants: A proposal for a clinical decision tree

OBJECTIVE

Esthetic complications in implant therapy today represent a clinical challenge, when the aim is to overcome the sequelae and obtain a pleasing result. The current scientific literature about this topic is scarce and often based on case reports and the personal opinions of clinicians.

CLINICAL CONSIDERATIONS

The aim of this article is to introduce a decision tree for diagnosis and treatment of complications, focusing on the pink esthetic of single-tooth implants and based on three diagnostic pillars (3D implant position, peri-implant hard-tissue anatomy, and peri-implant soft-tissue anatomy). Different shortcomings have been identified for each of the three diagnostic areas.

CONCLUSIONS

Following this tree, the article proposes treatment alternatives including soft- and hard-tissue reconstruction, implant submergence, orthodontic extrusion, and implant extraction in order to help clinicians establish a logical therapeutic sequence.

CLINICAL SIGNIFICANCE

Guidelines for adequate diagnosis and management of single implant-supported restorations with compromised esthetics is mandatory when attempt to overcome shortcoming in the pink esthetic result.

Accuracy of High-Frequency Ultrasound Scanner in Detecting Peri-implant Bone Defects

The purpose of this study was to assess the accuracy of high-frequency ultrasound (US) in the measurement of peri-implant bone defects in comparison with cone-beam computed tomography (CBCT) and micro-computed tomography (µCT). Bone defects were mechanically created around dental implants inserted into porcine ribs (n = 10). The bone samples were scanned by CBCT, µCT and US. Linear dimensions of the peri-implant defects were determined for supra-alveolar component, intra-bony component and width. The accuracy of measurements was evaluated with repeated-measures analysis of variance and the intra-class correlation coefficient at p ≤ 0.05. US underestimated the measurements for the supra-alveolar and intra-bony components in comparison to CBCT and µCT, and there were no statistically significant differences in the measurements of width. The intra-class correlation coefficient of US ranged from 0.96 to 0.98, whereas that for CBCT ranged from 0.77 to 0.97. US was accurate in measuring the width of peri-implant defects, although vertical measurements were underestimated by approximately 1 mm in comparison to those of CBCT and µCT.

Accuracy of detecting and measuring buccal bone thickness adjacent to titanium dental implants-a cone beam computed tomography in vitro study

OBJECTIVES

The aim of this study was to assess the accuracy of detecting and measuring buccal bone thickness (BBT) adjacent to titanium implants in cone beam computed tomography (CBCT) images.

STUDY DESIGN

Titanium implants (1, 2, or 3), abutments, and metal-ceramic crowns were inserted into 40 bone blocks with various BBTs. CBCT images were acquired in various settings: Voxel sizes (0.2 and 0.13 mm) and reconstruction section thicknesses (2.0 and 5.0 mm) were assessed by 3 examiners. True BBT was measured in digital photographs of the bone blocks. Buccal bone detection was evaluated by sensitivity and specificity. BBT was evaluated by 1-way analysis of variance (ANOVA) between the true and the CBCT measurements and by calculating the difference between the true measurement and the CBCT measurement (Di-BBT).

RESULTS

Detection of buccal bone exhibited high sensitivity (0.86-1) and low specificity (0.14-1). More implants in the field of view, large voxel size, and thick image reconstruction sections had a negative impact on buccal bone detection. ANOVA showed statistically significantly larger BBT for the CBCT measurements in all settings (1.07-1.21 mm) compared with the true measurements (0.85 mm). Di-BBT was mostly within 0.5 mm.

CONCLUSIONS

BBT adjacent to titanium implants is overestimated when evaluated on CBCT cross-sectional images.

Diagnostic performance of cone beam computed tomography in assessing peri-implant bone loss: A systematic review

OBJECTIVES

To evaluate the diagnostic performance of cone beam computed tomography (CBCT) in the assessment of peri-implant bone loss and analyze its influencing factors.

MATERIALS AND METHODS

Clinical and preclinical studies reporting diagnostic outcomes of CBCT imaging of peri-implant bone loss compared to direct reference measurements were sought by searching five electronic databases, PubMed, MEDLINE, EMBASE, Web of Science, and CINAHL Plus, and OpenGrey. QUADAS-2 criteria were adapted for quality analysis of the included studies. A qualitative synthesis was performed. Two meta-analysis models (random-effects and mixed-effects) summarized the area under receiver operating characteristic (AUC) curve observations reported in the selected studies. The mixed-effects meta-analysis model evaluated three possible influencing factors, "defect type," "defect size," and "study effect."

RESULTS

The initial search yielded 3,716 titles, from which 18 studies (13 in vitro and 5 animal) were included. Diagnostic accuracy of CBCT was fair to excellent in detecting in vitro circumferential-intrabony and fenestration defects, but moderate to low for peri-implant dehiscences, and tended to be higher for larger defect sizes. Both, over- and underestimation of linear measurements were reported for the animal models. The meta-analyses included 37 AUC observations from eight studies. The random-effects model showed significant heterogeneity. The mixed-effects model exhibited also significant but lower heterogeneity, and "defect type" and "study effect" significantly influenced the variability of AUC observations.

CONCLUSION

In vitro, CBCT performs well in detecting peri-implant circumferential-intrabony or fenestration defects but less in depicting dehiscences. Influencing factors due to other site-related and technical parameters on the diagnostic outcome need to be addressed further in the future studies.

Accuracy of Bone Measurements in the Vicinity of Titanium Implants in CBCT Data Sets: A Comparison of Radiological and Histological Findings in Minipigs

Purpose

The aim of this animal study was the determination of accuracy of bone measurements in CBCT (cone-beam computed tomography) in close proximity to titanium implants.

Material and Methods

Titanium implants were inserted in eight Göttingen minipigs. 60 implants were evaluated histologically in ground section specimen and radiologically in CBCT in regard to thickness of the buccal bone. With random intercept models, the difference of histologic measurements and CBCT measurements of bone thickness was calculated.

Results

The mean histological thickness of the buccal bone was 5.09 mm (CI 4.11–6.08 mm). The four raters measured slightly less bone in CBCT than it was found in histology. The random effect was not significant (p value 1.000). Therefore, the Intraclass Correlation Coefficient (ICC) was 98.65% (CI 100.00–96.99%).

Conclusion

CBCT is an accurate technique to measure even thin bone structures in the vicinity of titanium implants.

Accuracy of linear measurements around dental implants by means of cone beam computed tomography with different exposure parameters

OBJECTIVES

The aim of this study was to determine the accuracy of linear measurements around dental implants when using CBCT unit devices presenting different exposure parameters.

METHODS

Dental implants (n = 18) were installed in the maxilla of human dry skulls, and images were obtained using two CBCT devices: G1-Care Stream 9300 (70 kVp, 6.3 mA, voxel size 0.18 mm, field of view 8 × 8 cm; Carestream Health, Rochester, NY) and G2-R100 Veraview^® (75 kVp, 7.0 mA, voxel size 0.125 mm, field of view 8 × 8 cm; J Morita, Irvine, CA). Measurements of bone thickness were performed at three points located (A) in the most apical portion of the implant, (B) 5 mm above the apical point and (C) in the implant platform. Afterwards, values were compared with real measurements obtained by an optical microscopy [control group (CG)]. Data were statistically analyzed with the significance level of p ≤ 0.05.

RESULTS

There was no statistical difference for the mean values of bone thickness on Point A (CG: 4.85 ± 2.25 mm, G1: 4.19 ± 1.68 mm, G2: 4.15 ± 1.75 mm), Point B (CG: 1.50 ± 0.84 mm, G1: 1.61 ± 1.27 mm; G2: 1.68 ± 0.82 mm) and Point C (CG: 1.78 ± 1.33 mm, G1: 1.80 ± 1.09 mm; G2: 1.64 ± 1.11 mm). G1 and G2 differed in bone thickness by approximately 0.76 mm for Point A, 0.36 mm for Point B and 0.08 mm for Point C. A lower intraclass variability was identified for CG (Point A = 0.20 ± 0.25; Point B = 0.15 ± 0.20; Point C = 0.06 ± 0.05 mm) in comparison with G1 (Point A = 0.56 ± 0.52; Point B = 0.48 ± 0.50; Point C = 0.47 ± 0.56 mm) and G2 (Point A = 0.57 ± 0.51; Point B = 0.46 ± 0.46; Point C = 0.36 ± 0.31 mm).

CONCLUSIONS

CBCT devices showed acceptable accuracy for linear measurements around dental implants, despite the exposure parameters used.

Accuracy of Schneiderian membrane thickness: a cone-beam computed tomography analysis with histological validation

OBJECTIVES

Cone-beam computed tomography (CBCT) has been used in the literature to evaluate Schneiderian membrane thickness (SMT), but its accuracy has never been validated. The primary aim of this study was to compare the SMT measured by CBCT to the gold standard histological assessment. The correlations between SMT and anatomical structures of the maxillary sinus and alveolar bone were also tested.

MATERIALS AND METHODS

Fourteen fresh cadaver heads were used for the study, and 28 sinus lift augmentation procedures were performed to obtain the membrane samples. Samples were fixed in formalin and stained with hematoxylin-eosine and Masson trichrome. Specimens were measured by optic microscope at three points, and a mean was obtained. Anatomical landmarks were used to accurately position the CBCT slice, so the SMT could be measured in predetermined locations. Wilcoxon signed-rank test was used to compare values of histological and CBCT measurements, and Spearman's correlation coefficient was calculated to examine the relationship between thickness and anatomical parameters.

RESULTS

A total of 597 histological measurements were performed, and the mean SMT thickness was 0.30 ± 0.17 mm. The mean CBCT membrane thickness was 0.79 ± 0.52 mm. A statistically significant difference from histological and radiological readings was observed (P = 0.000). Interestingly, 87.77% histological measurements had membrane less than 0.5 mm in thickness compared to 26.66% in CBCT assessment.

CONCLUSIONS

Within the limitation of this study, the median histological Schneiderian membrane thickness was 0.30 mm. Cone-beam computed tomography assessment was 2.6 times higher than the histological examination.

Non-ionizing real-time ultrasonography in implant and oral surgery: A feasibility study

PURPOSE

Ultrasound imaging has potential to complement radiographic imaging modalities in implant and oral surgery given that it is non-ionizing and provides instantaneous images of anatomical structures. For application in oral and dental imaging, its qualities are dependent on its ability to accurately capture these complex structures. Therefore, the aim of this feasibility study was to investigate ultrasound to image soft tissue, hard tissue surface topography and specific vital structures.

MATERIAL AND METHODS

A clinical ultrasound scanner, paired with two 14-MHz transducers of different sizes (one for extraoral and the other for intraoral scans), was used to scan the following structures on a fresh cadaver: (i) the facial bone surface and soft tissue of maxillary anterior teeth, (ii) the greater palatine foramen; (iii) the mental foramen and (iv) the lingual nerve. Multiple measurements relevant to these structures were made on the ultrasound images and compared to those on cone-beam computed tomography (CBCT) scans and/or direct measurements.

RESULTS

Ultrasound imaging could delineate hard tissue surfaces, including enamel, root dentin and bone as well as soft tissue with high resolution (110 μm wavelength). The greater palatine foramen, mental foramen and lingual nerve were clearly shown in ultrasound images. Merging ultrasound and CBCT images demonstrated overall spatial accuracy of ultrasound images, which was corroborated by data gathered from direct measurements.

CONCLUSION

For the first time, this study provides proof-of-concept evidence that ultrasound can be a real-time and non-invasive alternative for the evaluation of oral and dental anatomical structures relevant for implant and oral surgery.

Assessment of buccal bone thickness of aesthetic maxillary region: a cone-beam computed tomography study

Purpose

The aim of this study was to analyze the anatomical dimensions of the buccal bone walls of the aesthetic maxillary region for immediate implant placement, based upon cone-beam computed tomography (CBCT) scans in a sample of adult patients.

Methods

Two calibrated examiners analyzed a sample of 50 CBCT scans, performing morphometric analyses of both incisors and canines on the left and right sides. Subsequently, in the sagittal view, a line was traced through the major axis of the selected tooth. Then, a second line (E) was traced from the buccal to the palatal wall at the level of the observed bone ridges. The heights of the buccal and palatal bone ridges were determined at the major axis of the tooth. The buccal bone thickness was measured across five lines. The first was at the level of line E. The second was at the most apical point of the tooth, and the other three lines were equidistant between the apical and the cervical lines, and parallel to them. Statistical analysis was performed with a significance level of P≤0.05 for the bone thickness means and standard deviations per tooth and patient for the five lines at varying depths.

Results

The means of the buccal wall thicknesses in the central incisors, lateral incisors and canines were 1.14±0.65 mm, 0.95±0.67 mm and 1.15±0.68 mm, respectively. Additionally, only on the left side were significant differences in some measurements of buccal bone thickness observed according to age and gender. However, age and gender did not show significant differences in heights between the palatal and buccal plates. In a few cases, the buccal wall had a greater height than the palatal wall.

Conclusions

Less than 10% of sites showed more than a 2-mm thickness of the buccal bone wall, with the exception of the central incisor region, wherein 14.4% of cases were ≥2 mm.