Posterior Sites Research Articles

Efficacy of Two Different Hydrodynamic Sinus Lift Systems for Atraumatic Elevation in Immediate Implant Placement.

To evaluate the efficacy of two hydrodynamic sinus lifting procedures and to successfully place immediate implants in maxillary posterior sites that have a compromised native bone as a result of periodontal or endodontic disease. A total of 26 patient sites were enrolled with 13 sites each in the Minimally Invasive Antral Membrane Balloon Elevation (MIAMBE) and Drill Integrated Hydrodynamics for the transcrestal sinus floor elevation (DIHSFE) groups who received transcrestal sinus floor elevation followed by immediate implant placement. Clinical parameters such as sinus membrane perforations, nasal bleeding, postoperative sinusitis, VAS scores at Day-7 for pain and discomfort, primary implant stability and time taken were evaluated. The DIHSFE had greater sinus membrane perforations and incidence of nasal bleeding when compared with MIAMBE with (p = 0.066) and (p = 0.141). Post-operative sinusitis was evident in both the groups with (p = 0.619). The mean VAS score was statistically significant between both the groups (p ≤ 0.005). The insertion torque values, and mean time taken for surgical procedure was not statistically significant between groups. The present study highlighted that MIAMBE is superior to DIHSFE in its ability to cause less severe patient morbidities and post-operative complications.

Perinatal nicotine exposure relates to stimulus-locked event-related potentials in early adolescence during an emotional go/no-go task

Nicotine exposure is associated with negative consequences on the developing brain, both in utero and after birth. We investigated the relationship between perinatal nicotine exposure and electroencephalographic brain activity recorded during an emotional faces Go/No-Go task among adolescents. Seventy-one adolescents aged 12–15 years completed a Go/No-Go task using fearful and happy faces. Parents completed questionnaire measures of their child's temperament and self-regulation and retrospectively reported on nicotine exposure during the perinatal period. Perinatally exposed children (n = 20) showed increased and prolonged frontal event-related potential (ERP) differentiation in stimulus-locked analyses; that is, greater emotion and condition differentiation in comparison with their non-exposed peers (n = 51). However, non-exposed children showed greater late emotion differentiation recorded over posterior sites. Response-locked ERP differences were not found. ERP effects were not related to temperamental, self-regulatory, or parental education and income-related factors. This study is the first to demonstrate a relationship between perinatal nicotine exposure and ERPs in an emotional Go/No-Go task among adolescents. Findings suggest that while conflict detection remains intact for adolescents with perinatal nicotine exposure, their attentional allocation to behaviourally relevant stimuli may be magnified to beyond optimal levels, particularly when emotion is salient in information processing. Future studies can extend these findings by isolating prenatal nicotine exposure and comparing its effects to isolated postnatal exposure and clarifying the implications of the face and performance processing differences in adolescence.

Change in CT Value at Mandibular Ramus After Mandibular Setback and Advancement Surgery With Bicortical Absorbable Plate Fixation.

This study aimed to evaluate changes in computed tomography (CT) value of ramus bone after sagittal split ramus osteotomy (SSRO) in class II and class III patients using absorbable plates and screws. In the retrospective study, the participants were female patients with jaw deformities who underwent bilateral SSRO with Le Fort I osteotomy. Maximum CT values (pixel values) of lateral and medial cortexes at anterior and posterior sites of the ramus were measured preoperatively and 1 year postoperatively by using horizontal planes at the mandibular foramen level (upper level) and 10mm under the mandibular foramen level (lower level) parallel to Frankfurt horizontal plane. Fifty-seven patients and 114 sides (28 class II: 56 sides and 29 class III: 58 sides) were evaluated. Although CT values decreased at most sites of the ramus cortical bone after 1 year of surgery, they increased at the posterior-medial site at the upper level in class II ( P =0.0012) and the lower level in class III ( P =0.0346). This study suggested that bone quality at the mandibular ramus could change after 1 year of surgery, and there could be differences between mandibular advancement and setback surgery.

The Complete Digital Workflow in Fixed Prosthodontics Updated: A Systematic Review

Digital applications have changed therapy in prosthodontics. In 2017, a systematic review reported on complete digital workflows for treatment with tooth-borne or implant-supported fixed dental prostheses (FDPs). Here, we aim to update this work and summarize the recent scientific literature reporting complete digital workflows and to deduce clinical recommendations. A systematic search of PubMed/Embase using PICO criteria was performed. English-language literature consistent with the original review published between 16 September 2016 and 31 October 2022 was considered. Of the 394 titles retrieved by the search, 42 abstracts were identified, and subsequently, 16 studies were included for data extraction. A total of 440 patients with 658 restorations were analyzed. Almost two-thirds of the studies focused on implant therapy. Time efficiency was the most often defined outcome (n = 12/75%), followed by precision (n = 11/69%) and patient satisfaction (n = 5/31%). Though the amount of clinical research on digital workflows has increased within recent years, the absolute number of published trials remains low, particularly for multi-unit restorations. Current clinical evidence supports the use of complete digital workflows in implant therapy with monolithic crowns in posterior sites. Digitally fabricated implant-supported crowns can be considered at least comparable to conventional and hybrid workflows in terms of time efficiency, production costs, precision, and patient satisfaction.

Accuracy of automatic and manual dynamic navigation registration techniques for dental implant surgery in posterior sites missing a single tooth: A retrospective clinical analysis.

To assess the relative accuracy of manual (U-shaped tube) and automatic (two-in-one) dynamic navigation registration techniques for implant surgery performed in posterior sites missing one tooth. This study included 58 partially edentulous patients with 58 implants, including 31 and 27 in the manual and automatic groups. Deviations between the planned and actual implant placement were assessed. The angular deviation in the overall study cohort was 2.54 ± 1.21°, while the 3D deviations at the implant platform and apex were 0.90 ± 0.46 mm and 1.04 ± 0.47 mm, respectively. The respective angular deviations in the manual and automatic groups were 2.82 ± 1.17° and 2.21 ± 1.19° (p > .05), while platform deviations were 0.89 ± 0.48 mm and 0.91 ± 0.45 mm (p > .05), and apex deviations were 0.99 ± 0.48 mm and 1.11 ± 0.46 mm (p > .05). No significant differences in absolute buccolingual, mesiodistal, or apicocoronal deviations were detected between these groups at either level (p > .05) nor were did deviation distributions differ in the buccolingual, mesiodistal, or apicocoronal directions at the platform or apex levels (p > .05). Manual and automatic dynamic navigation registration techniques can achieve excellent accuracy when placing implants in posterior sites missing a single tooth. The two-in-one automatic registration technique can reduce the amount of time and intraoperative steps necessary to complete the registration process relative to the manual U-shaped tube registration technique. Further follow-up studies are necessary to expand on these results.

Investigating the Association of Patient Body Mass Index With Posterior Subcutaneous Fat Thickness in the Cervical Spine: A Retrospective Radiographic Study.

Although BMI is often used as a surrogate for posterior cervical subcutaneous fat thickness (SFT), the association of BMI with cervical SFT is unknown. We performed a retrospective radiographic study to analyze the relationship between BMI and cervical SFT. This was a retrospective cohort study of patients with cervical CT scans. SFT was assessed by measuring the distance (mm) from the spinous processes of C2-C7 to the skin edge. Pearson correlations and linear regression were used to analyze the relationship between BMI and SFT. One-way ANOVA was used to analyze differences in C2-C7 distances while stratifying by BMI. A total of 96 patients were included. BMI had a moderate correlation with average C2-C7 (r=0.546, p < 0.05) SFT, and a weak to moderate correlation with each individual C2-C7 distance. The strongest correlation was at the C7 level (r= 0.583, p < 0.05). These analyses remained significant controlling for potential confounders of patient age, sex, and diabetes. No difference was found in the average C2-C7 distance in patients with BMIs of 25-30 compared to those with BMIs of 30-40 (p=0.996), whereas in patients with BMI <25 and BMI >40, differences were significant (p < 0.05). BMI is not strongly correlated with SFT in the cervical spine. Although BMI less than 25 or greater than 40 is correlated with respectively decreased or increased cervical SFT, BMI of 25-40 is not correlated with cervical SFT. This is clinically important information for surgeons counseling patients on perioperative risk before undergoing cervical spine procedures, namely infection. Further research delineating the relationship between posterior SFT and surgical site infection in the cervical spine is warranted.

Accuracy comparison of bilateral versus complete arch interocclusal registration scans for virtual articulation

Statement of problemAlternatives to the bilateral interocclusal registration scanning technique to improve virtual articulation have not been fully investigated. PurposeThe purpose of this in vitro study was to compare the accuracy of virtually articulating digital casts by using bilateral interocclusal registration scans versus a complete arch interocclusal scan. Material and methodsA set of maxillary and mandibular reference casts were hand-articulated and mounted on an articulator. The mounted reference casts were scanned, and the maxillomandibular relationship record was scanned 15 times using 2 different scanning techniques, the bilateral interocclusal registration scan (BIRS) and complete arch interocclusal registration scan (CIRS), with an intraoral scanner. The generated files were transferred to a virtual articulator, and each set of scanned casts was articulated using BIRS and CIRS. The virtually articulated casts were saved as a set and transferred to a 3-dimensional (3D) analysis program. The scanned casts were set in the same coordinate system as the reference cast and overlaid on top of the reference cast for analysis. Two anterior and 2 posterior points were selected to determine points of comparison between the reference cast and test casts virtually articulated with BIRS and CIRS. The mean discrepancy between the 2 test groups and the anterior and posterior mean discrepancy within each group were tested for significance by using the Mann-Whitney U test (α=.05). ResultsA significant difference was found between the virtual articulation accuracy of BIRS and CIRS (P<.001). The mean deviation for BIRS was 0.053 ±0.051 mm and that for CIRS was 0.265 ±0.241 mm. Furthermore, significant differences were found between the anterior and posterior deviations in both BIRS (P=.020) and CIRS (P<.001). The mean deviation for BIRS was 0.034 ±0.026 mm in the anterior and 0.073 ±0.062 mm in the posterior. The mean deviation for CIRS was 0.146 ±0.108 mm anteriorly and 0.385 ±0.277 mm posteriorly. ConclusionsBIRS was more accurate than CIRS for virtual articulation. Moreover, the alignment accuracy of anterior and posterior sites for both BIRS and CIRS exhibited significant differences, with the anterior alignment exhibiting better accuracy in relation to the reference cast.

Degree of Hearing Loss in Association with Site of Tympanic Membrane Perforation: A Systematic Review

Background: Tympanic Membrane perforation is commonly seen in a middle ear pathology called chronic otitis media that affects at least 0.5% of the total world population. Aim: To evaluate the nature of hearing loss in tympanic membrane perforation (TMP) based on the site of perforation. Study design: Systemic review. Methodology: All the articles were taken from Google Scholar, Cochrane Library, Pub Med, NCBI (NLM Catalog) and HEC Digital Library within five years range: 2017-2021. All the researchers were screened widely by a well-intentioned peer review group. Results: Articles (n=19) were included in the review. In case of site of perforation, most of the articles compared anterior site with posterior and central, depicting that posterior site causes more hearing loss than anterior site, while central perforations had greater hearing loss than anterior/posterior site. The total sample size of these 19 articles collectively was (n=1,650). Most severe hearing loss with respect to site of TM perforation was demonstrated in only 1 study (5.26%) out of 19 and that was 61-80 decibels. One study (5.26%) showed no correlation between hearing loss and site of TM perforation. Practical Implication: Sometimes, it is seen in ENT practices that there was a dilemma regarding the severity of hearing loss with respect to site of perforation. It benefited otolaryngologists to find a systematic review on the provided topic, to learn and know more about the association between hearing loss and site of TMP. Conclusion: We concluded that anterior sites of perforations cause less hearing loss than posterior, central or marginal. Keywords: Hearing loss; Tympanic membrane perforation; Site of TM perforation.

Comparison of Virtual Intersection and Occlusal Contacts between Intraoral and Laboratory Scans: An In-Vivo Study.

The inaccurate maxillomandibular relationship of virtual casts following alignment by the vestibular scan may result in intersection (intermesh penetration) between opposing dental arch surfaces. Intersection occurs at short interocclusal distances in the occlusal contact area (OCA) and may result in infra-occluded definitive restorations. The purpose of this clinical study was to compare initial (by the proprietary scanner software) and new alignments (by a standalone 3D software) of virtual casts regarding OCA and intersection failure. New alignments aimed to rectify intersections by refinement of occlusal contacts. The virtual casts of 30 patients following digital and conventional impression-taking were analyzed, which were acquired for single implant restoration in the posterior site. Digital impressions were performed by both IOS 1 (3M True Definition) and IOS 2 (TRIOS 3), either as complete- or partial-arch scans, respectively. Mounted gypsum casts were digitized as complete-arch by a laboratory scanner (LS) in enabled and disabled mode to avoid intersection [LS (+)/LS (-)]. All virtual casts were newly aligned by a 3D software. The difference of the OCA and the area of intersection were calculated for initial and new alignments, using interocclusal distance ranges of 0-100 μm, 0-10 μm or <0 μm (=intersection). The difference of the OCA was compared using a linear mixed model. The distribution of occlusal contact points per modality and alignment was assessed independently by three observers and estimated by inter- and intraclass correlation (ICC) coefficients. Virtual casts following initial alignment demonstrated intersections irrespective of the modality. The mean area of the intersection was most for IOS 2 (79.23 mm2), followed by IOS 1 (48.28 mm2), LS (-) (2.77 mm2), and LS (+) (2.01 mm2) in partial-arch scans. Complete-arch scans demonstrated an area of intersection of 70.63 mm2 for IOS 1 followed by 65.52 mm2 (IOS 2), 6.13 mm2 [LS (-)] and 2.76 mm2 [LS (+)]. Newly aligned scans showed no intersections. The overall distribution of occlusal contact points demonstrated moderate reliability (ICC 0.63). Good reliability could be observed (ICC 0.9) for LS (-) scans. Intersections in the area of occlusal contact points are a phenomenon restricted to virtual casts, which should be considered in CAD/CAM. Initial alignments of LS are less affected by this virtual phenomenon, and contact points may be more distinct according to their anatomic region compared to IOS. Furthermore, intersections can be rectified in a 3D software by adjustment of the maxillomandibular relationship.

Differential Cortical Volumetric Bone Mineral Density within the Human Rib

Introduction: The human rib provides a vital role in the protection of thoracic contents. Rib fractures are linked to injuries and health complications that can be fatal. Current clinical methods to assess fracture risk and bone quality are insufficient to quantify intra-element differences in bone mineral density (BMD) or to identify at-risk populations. Utilizing quantitative computed tomography (QCT) provides accurate measures of volumetric BMD (vBMD) along the length of the rib which can help delineate factors influencing differential fracture risk. Methodology: One mid-level rib was obtained from 54 post-mortem human subjects (PMHS) and scanned using QCT. Volumes of interest (VOIs) were created for sites at 30%, 50%, and 75% of rib total curve length. Mean Hounsfield units (HU) from each VOI were converted to vBMD using a scan-specific cortical phantom calibration curve. Additionally, rib and lumbar areal BMD (aBMD) were obtained from a sub-sample of 33 PMHS. Results: Significant differences in vBMD were found between all sites within the rib (p<0.01). When analyzed by sex, vBMD between the 30% and 50% site were no longer different in either males or females (p>0.05). Separating the sample into discrete age groups demonstrated the relative differences in vBMD between sites diminished with age. Further, age as a continuous variable significantly predicted rib vBMD at all sites (p<0.05), but with little practical or clinical utility (R2, 14.7- 22.8%). Similarly, only small amounts of variation in rib vBMD were explained from DXA lumbar and rib aBMD (R2 , 1.1-21.8%). Conclusions: vBMD significantly decreased from the posterior (30%) site to the anterior (75%) site within the rib which may represent adaptation to localized mechanical loading. These differences could result in differential fracture risk across the rib. As thoracic injury can be fatal, using comprehensive assessments of bone quality that accounts for variation within the rib may provide more accurate identification of at-risk populations.

Risk factors for early implant failure: a retrospective-multicentric study of 2323 implants in screw retained fixed full arch rehabilitation

Objectives: The aim of this retrospective study was to investigate possible risk factors for early implant failure in screw retained fixed full-arch rehabilitation. Methods: data of 487 patients (2323 implants) treated with full-arch rehabilitation supported by same implants brand were collected for the time period from 2017 to 2020 and examined to evaluate early implants failure rates. The following data were collected for statistical analysis: sex, age, health disorders (diabetes and hypertension) and bad habit (smoke) of the patient, location of the implant (maxilla or mandible, anterior or posterior site), type of implant's healing and bone regeneration procedures. Chi-squared test, bivariate comparison analysis and univariate mixed model analysis were used to estimate the effect of both patient-related and implant related variables on early implant failure as a potential risk factors. Results: 487 patients were included, 218 females (62.3 ± 9.14 of age) and 269 males (62.8 ± 10.11 of age) in 30 private institutions for a total of 2323 implants placed and a total of 526 screw retained fixed full arch rehabilitation. A total of 40 out of 2323 (1.7%) implants failed prematurely within 1 year, 32 in the maxilla 8 in the mandible. Bivariate comparison analysis and univariate mixed model analysis showed that female patient, implant placed in maxilla, age &lt;61 years and submerged healed implants showed a statistically significant higher failure rate among the risk factors considered. Conclusions: Implants placed in the upper jaw and their modality of healing seems to be associated with a higher risk of early implant failure.

180 LONG TERM FOLLOW UP OF A NON-PROGRESSIVE LEFT MAIN CORONARY ARTERY FISTULA TO RIGHT ATRIUM

Abstract A 63 years old man, with multiple cardiovascular risk factor, presented at the emergency department with a transient ischemic attack during an hypertensive crisis. Electrocardiogram revealed a sinus rhythm and no sign of ischemia. No critical stenosis were detected at ultrasonography of the supra-aortic trunks. Brain CT showed an arachnoid cyst in right posterior cerebellar site. Transthoracic echocardiographic showed normal wall motion with a left ventricular ejection fraction of 66%. The transesophageal echocardiography, performed for searching possible emboligenic heart disease, revealed a fistulous aneurysmal formation arising from the left main coronary artery. Angio-CT confirmed a CAF between distal left main coronary artery and right atrium, with a retro-aortic serpiginous course and an ectasic vascular structure (above 8.35 mm), this pathological vessel also had an aneurismatic formation of maximum diameter of 1 cm. CT scan detected also a 50% soft eccentric plaque in mid circumflex coronary artery and a less than 50% soft eccentric plaque in the right coronary artery. An elective hospitalization was performed in order to better assess the CAF. Coronary angiography revealed no significant coronary atherosclerotic disease and confirmed the CAF with its convoluted course. No left to right shunt was found either in cardiac magnetic resonance (Qp/Qs close to 1) or in right heart catheterization. Maximal stress test with cycloergometer was negative for clinical and electrocardiographic inducible ischemia (120W). CAF is a rare vascular abnormality, occurring in only 0.002% of the general population. The majority of CAFs have a congenital origin, but occasionally they may be acquired after cardiac surgery or repeated myocardial biopsies in cardiac transplantation. The CAFs may increase in size over time, although this does not occur invariably, and complications include: myocardial ischemia (due to myocardial ‘steal’), thrombosis and embolism, heart failure, atrial fibrillation, rupture, endocarditis/endarteritis, arrhythmias and also spontaneous rupture of the CAF causing hemopericardium. Current treatment options for CAF include surgery or transcatheter closure. Considered the age of the patient, the absence of clinical symptoms and the absence of left to right shunt, a conservative strategy was chosen. The patient had strict follow up, with clinical and echocardiographic assessment every 6 months, and with annually CT scan and stress test. During these 9 years of follow up the CAF remained stable, and the patients clinically asymptomatic.

CBCT analysis of crestal soft tissue thickness before implant placement and its relationship with cortical bone thickness.

The importance of crestal soft tissue thickness and its influence in peri-implant tissue health has been evaluated in few clinical studies. Cone beam computed tomography imaging offers a unique opportunity to investigate variations in crestal soft tissue thickness. The aim of this retrospective study was to evaluate the possible correlation between crestal soft tissue thickness and hard tissue measurements on CBCT images, and to compare crestal soft tissue thickness among different patients and edentulous site groups. CBCT images of partially edentulous adult patients treated at ECU School of Dental Medicine were evaluated. 267 patients with 321 edentulous sites were included. Demographic data were collected from electronic health records. Cross-sectional CBCT images at the center of each edentulous site were used to measure soft tissue and hard tissue parameters. Linear mixed models were used to compare crestal soft tissue thickness and hard tissue measurements by gender, age groups, and edentulous sites. Pearson correlation was applied to evaluate the correlation between crestal soft tissue thickness and different hard tissue measurements. Association between crestal soft tissue thickness and independent variables (gender, age groups, edentulous sites) was evaluated using repeated measure logistic regression, while the crestal soft tissue thickness was dichotomized by a threshold of 2mm. Mean age of patients included was 60 (range 21-85years). Female to male ratio was 1.07. Mean crestal soft tissue thickness of all non-grafted native bone sites was 2.17mm. Mean thickness of cortical bone at alveolar crest was 0.94mm. Thickness of buccal and lingual cortical plates 5mm apical to alveolar crest were 1.17mm and 1.58mm, respectively. Pearson's correlation showed moderate positive correlation among hard tissue measurements, but weak correlation between soft tissue thickness and hard tissue measurements. Anterior sites [OR = 3.429 (1.100-10.69)] and maxillary posterior sites [OR = 1.937 (1.077-3.482)] had higher odds of presenting with more than 2mm of soft tissue at the alveolar crest. More than half of the patients had crestal soft tissues at edentulous sites thicker than 2mm. Thickness of crestal soft tissue was not significantly associated with hard tissue measurements. Edentulous anterior sites and maxillary posterior sites presented with thicker crestal soft tissue at alveolar crest as compared to mandibular posterior sites.

Simultaneous 3D Reconstruction and Implant Placement Using Allogenic Laminar Bone Membranes in Atrophic Mandible. A Comparative Clinical Study

Aim: to compare the outcome of allogenic bone sheets clinically and radiographically in posterior mandibular vertical augmentation in Luhr class III cases with simultaneous implant placement using autogenous versus xenografts. Patients and methods: this study was based on a total of 12 implants placed in 4 patients, 2 of which were males and 2 females. Patients were divided into 2 groups, both treated with implants placed with exposed threads 3 mm crestally and covered buccolingually with the laminar bone membrane; group 1 received autogenous bone obtained from the same surgical site using 4.5 diameter ACM bur mixed with PRP and packed around the crestally exposed implant threads. Group 2 received xenograft bone particles mixed with PRP and packed around the crestally exposed implant threads in the same manner. Results: CBCT was done pre-operatively, immediate post-operatively and 4 months post-operatively for each implant to compare the bone gain radiographically. In group 1, the mean amount of residual bone height pre-operatively was 7.8 mm (SD 0.86) and increased to 14.44 mm (SD 1.75) and 14.1 mm (SD 1.85) immediate and 4 months post-operatively, respectively. The mean amount of bone gain after 4 months was 6.3 mm, denoting a minimal amount of graft loss during the first 4 postoperative months was 0.27 mm (less than 2%). In group 2, the mean amount of residual bone height pre-operatively was 8.37 mm (SD 0.99) and increased to 12.86 mm (SD 1.75) and 12.53 mm (SD 1.65) immediate and 4 months post-operatively, respectively. The mean amount of bone gain after 4 months was 4.16 mm, denoting a minimal amount of graft loss during the first 4 postoperative months was 0.33 mm (less than 3%). Upon comparing bone gain in both groups, Group I (Autogenous) had a bone gain of 6.33 mm versus 4.16 mm for Group II (Xenograft). Denoting more gain in Group I (autogenous). While the amount of graft loss between the immediate and 4 months postoperative CBCT was less than 2% and less than 3% in the autogenous versus the xenograft group respectively. Conclusion: Cases initially lacking keratinized mucosa will need soft tissue intervention along with this technique. Exposure after 4 months appeared to have been too early, which lead to bone loss and exposed threads. Bilateral augmentation has led to patients using the grafted edentulous sites for mastication early following soft tissue healing, prior to prosthetics, which might suggest that tooth-bounded posterior edentulous sites might be a better candidate for such technique. Results were clinically different than radiographically in the CBCT, so longer lag time is recommended before loading.

Accuracy of dynamic implant navigation surgery performed by a novice operator.

The main objective was to evaluate the accuracy of dynamic navigation-guided surgery (DNGS) for implant positioning performed by a novice operator. The secondary objectives were to analyze the operator's learning curve and identify possible complications deriving from the technique. Twenty-five implants were placed in eight partially edentulous human heads. Preoperative CBCT scans were imported to planning software to determine the implant positions. Implants were placed using a dynamic navigation system. Postoperative CBCTs were superimposed onto the implant planning images. Discrepancies between the virtually planned implant positions and the postoperative positions were evaluated by measuring horizontal platform deviation, apex deviation, apicocoronal (vertical) deviation, and angular deviation. Mean platform, apex, vertical, and angle deviations were 1.55 ± 0.81 mm, 2.45 ± 0.84 mm, 1.59 ± 0.70 mm, and 5.56 ± 4.03 degrees, respectively. No significant differences were found between the maxilla and mandible or between anterior and posterior sites. A flat learning curve was observed, with the exception of the implant platform, where a tendency toward improvement in accuracy was observed between the 8th and the 17th implant placed. No complications were reported. Based on the results of a study performed by a novice operator on a cadaveric model, DNGS allows accurate implant placement within a 2-mm safety margin in terms of implant platform and vertical positions, and a 3-mm margin in apical vicinities. The technique requires practice to learn the required eye-hand coordination. (Int J Comput Dent 2022;25(4):377-0; doi: 10.3290/j.ijcd.b2588207).

Antigingivitis efficacy of a sodium bicarbonate toothpaste: Pooled analysis.

The objective of this study was to investigate the antigingivitis and antiplaque treatment effect of a toothpaste containing 67% w/w sodium bicarbonate, at the individual tooth site, tooth region and whole mouth (overall) level, by way of a pooled analysis of data from similarly designed clinical trials. Six randomized controlled GSKCH clinical trials, 12-24 weeks in duration, were selected based on pre-specified criteria which included access to patient level data, pre-treatment dental prophylaxis, >20 bleeding sites and mild-moderate gingivitis at screening and use of 67% sodium bicarbonate toothpaste and non-sodium bicarbonate (regular) toothpaste (negative control) for ≥4 weeks. Efficacy outcomes comprised plaque index (TPI), modified gingival index (MGI) and gingival bleeding (bleeding index (BI), number of bleeding sites (BS)). Treatment comparisons were made using ANCOVA for whole mouth (overall) scores and by tooth site region (facial overall, lingual overall; margin/body overall, facial margin/body, lingual margin/body; papillae/interproximal overall, facial papillae/interproximal, lingual papillae/interproximal). Pooled data for BI, MGI, and TPI at individual tooth sites was plotted as a mouthmap to summarize treatment response (change from baseline) by tooth site, at the 24-week timepoint. For all measures, whole mouth and for all tooth regions at all post-treatment timepoints, significant (p < 0.001) differences in favour of the 67% sodium bicarbonate toothpaste compared with control were observed. At the 24-week timepoint, facial regions demonstrated greater improvements than lingual regions, with the greatest between treatment improvement seen for the facial-papillae regions for bleeding (BS/BI), facial-margin regions for MGI and facial-body regions for TPI. All individual tooth sites demonstrated numerically greater reductions from baseline for the 67% sodium bicarbonate toothpaste than the control toothpaste following 24 weeks use, with the greatest improvements (change from baseline) seen for posterior and papillae tooth sites for bleeding, margin tooth sites for MGI and body tooth sites for TPI. This pooled analysis of patient level-data, limited to GSKCH long-term gingivitis clinical studies, demonstrates that twice daily use of a 67% sodium bicarbonate toothpaste effectively removes plaque from all tooth sites, and results in clinically significant improvements in measures of gingival health, overall and for all the tooth regions investigated, compared with a non-sodium bicarbonate (regular) toothpaste following 24 weeks twice daily use.

Biomechanical Comparison of 4 Transsacral Fixation Constructs in a Type 61C, Zone II Pelvic Fracture Model.

OTA/AO 61C pelvic ring injuries are vertically unstable because of complete sacral fractures combined with anterior ring injury. The objective of this study was to compare the biomechanical characteristics of 4 transsacral screw constructs for posterior pelvic ring fixation, including one that uses a novel fixation method with a pair of locked washers with interdigitating cams. Type C pelvic ring disruptions were created on 16 synthetic pelvis models. Each pelvis was fixated with an S2 screw in addition to being allocated to 1 of 4 transsacral constructs through S1: (1) 8.0-mm screw, (2) 8.0-mm bolt, (3) 8.0-mm screw locked with a nut, and (4) 8.00-mm screw locked with a nut with the addition of interdigitating washers between the screw head and ilium on the near cortex, and ilium and nut on the far cortex. The anterior ring fractures were not stabilized. Each pelvis underwent 100,000 cycles at 250 N and was then loaded to failure using a unilateral stance testing model. The anterior and posterior osteotomy sites were instrumented with pairs of infrared (IR) light-emitting markers, and the relative displacement of the markers was monitored using a three-dimensional (3D) motion capture system. Displacement measurements at 25,000; 50,000; 75,000; and 100,000 cycles and failure force were recorded for each pelvis. The novel washer design construct performed better than the screw construct with less posterior ring motion at 75,000 ( P = 0.029) and 100,000 cycles ( P = 0.029). The novel interdigitating washer design may be superior to using a screw construct alone to achieve rigid, locked posterior ring fixation in a synthetic pelvis model with a Type C pelvic ring disruption.

A Descriptive Study on the Prevalence of Peri-Implantitis with Severe Disease and Bone Loss

Background: Peri-implantitis is a common complication in dental implant. It is associated with peri‐implant pocket formation and loss of supporting bone which hinder the treatment of replacement of missing teeth in partially or fully edentulous patients. Aim of the Study: The aim of this study was to assess the prevalence of peri-implantitis with severe disease and bone loss. Methods: This descriptive study was conducted in the post oral implant care unit of Banasree Dental and Implant Center and German Dental &amp; Implant Center, Dhaka, Bangladesh during the period from February 2013 to January 2022. The sample size of this study was 99. Result: Among 99 study people, mean age was 56.4 years (SD±8.1 years). Majority of the study people (53.5%) were female. From the past history, we found that 21.2% study people had smoking habit, 19.2% had diabetes, 11.1% had hypertension, 39.4% had history of periodontitis, 6.1% had osteoporosis, 2% had history of chemotherapy and 1% had history of radiotherapy. Mean follow-up was 920 days (SD±37 days). Mean implant width was 4.1 mm (SD±0.5 mm) and mean implant length was 11.0 mm (SD±0.6 mm). Most of the implants (63.6%) were located in posterior site. Mean longitudinal bone changes in mesial part were 3.0 mm (SD±4.2 mm). Mean longitudinal bone changes in distal part were 3.4 mm (SD±5.6 mm). Mean marginal bone loss was 4.3 mm (SD±3.3 mm). Mean probing depth was 4.2 mm (SD±2.1 mm). Conclusion: Older people specially women are more affected by peri-implantitis. Smoking habit, several diseases and history of periodontitis are associated with more risk for peri-implantitis. We have found peri-implantitis patients associated with severe bone loss and deep probing depth.

Dental implant proximity to adjacent teeth: A retrospective study.

The purpose of this study was to assess the occurrence and prognosis of dental implant proximity or direct contact with the adjacent tooth and to evaluate the symptoms and complications in both the implant and the adjacent tooth. We then elaborate on treatment modalities and discuss the prevention of this phenomenon. This retrospective study was conducted based on the dental clinical and radiographic records of 43 patients with implant-tooth proximity of <1.0 mm or direct implant-tooth contact. Multivariate Bayesian logistic regression was performed to examine the influence of individual variables on correcting major clinical variables. In the multivariate regression analysis, the rate of occurrence of tooth symptom decreased by about 95% with every increase of 1.0 mm distance between implant and tooth (odds ratio [OR]=0.1, 95% confidence interval [CI]: 0.004-0.680, p=0.024). In the case of implant-tooth root proximity in the anterior area, the OR of peri-implantitis occurrence was 30.4-fold greater than in posterior sites (OR=30.4, 95% CI: 1.189-785.914, p=0.040). Implant-tooth root proximity or direct implant-tooth contact is an iatrogenic factor that causes various complications, including devitalization of the adjacent tooth and peri-implantitis. Proactive prevention with surgical stents and intra-operative periapical radiographs is needed. If proximity or contact is found during surgery, repositioning of the fixture to the correct location is recommended in order to maintain peri-implant health and prevent complications.

Alveolar bone measurements in magnetic resonance imaging compared with cone beam computed tomography: a pilot, ex-vivo study

Objectives To compare alveolar bone height and width measurements from zero-echo-time MRI (ZTE-MRI) and cone beam CT (CBCT), in human specimens. Material and methods Twenty posterior edentulous sites in human cadaver specimens were imaged with CBCT and ZTE-MRI. Bone height and width at 1, 3, 5, 7 and 9 mm from the top of the alveolar ridge was measured by two trained observers in cross-sections of a site where an implant was to be planned. Twenty percent of the sample was measured in duplicate to assess method error and intra-observer reproducibility (ICC). The differences between CBCT and ZTE-MRI measurements were compared (t-test). Results Inter- and intra-observer reproducibility was >0.90. The method error (average between observers) for bone height was 0.45 mm and 0.39 mm, and for bone width (average) was 0.52 mm and 0.80 mm (CBCT and ZTE-MRI, respectively). The majority of the bone measurement differences were statistically insignificant, except bone width measurements at 5 mm (p ≤ .05 for both observers). Mean measurement differences were not larger than the method error. Conclusion ZTE-MRI is not significantly different from CBCT when comparing measurements of alveolar bone height and width.