Proximal Plate Research Articles

Minimally invasive percutaneous plate osteosynthesis for treatment of proximal humeral shaft fractures.

The objective of this study was to evaluate the feasibility and safety of a minimally invasive percutaneous plate osteosynthesis (MIPPO) procedure for proximal humeral shaft fractures using lateral minimal proximal and distal approaches and lateral bridge plating with primary radial nerve control, and to assess its clinical and radiographic outcomes. A retrospective review was done for the medical records of adult patients admitted for fracture of the proximal humeral shaft without associated injury to the ipsilateral upper limb and who consented to undergo a novel MIPPO technique herein reported. Patients were reviewed at regular follow-up periods and assessed at a final follow-up for evaluation of Constant, normalized Constant, and QuickDASH scores. There were 21 adult patients with mean age of 56years. Three patients were lost from early follow-up; one of them had post-operative radial nerve paralysis. Eighteen patients were reviewed for the purpose of this study at a mean of 20months of final follow-up; among them, one patient developed post-operative radial nerve paralysis with complete recovery after three months. Bone healing was achieved without any malalignment in 17 patients at a mean of 15weeks, and one patient developed nonunion. At final assessment (mean, 20months), the mean values of Constant, normalized Constant, and QuickDASH scores were 84 (range, 59 to 100), 95 (range, 73 to 100), and 5 (range, 0 to 18.2) respectively. Compared to pre-reported methods of MIPPO, this technique of lateral proximal and distal mini-approaches with lateral bridge plating after primary control of the radial nerve seems safe and feasible for proximal humeral shaft fractures. It gives good clinical and radiographic results with excellent restoration of upper limb function, very low incidence of post-operative radial nerve injury, and high rate of bone union in good alignment.

Fixation of proximal humerus fracture in adult by locking plate: Clinical study

p>Aim: The present study aimed to examine the functional outcome of the locking plate in theproximal humerus fracture treatment. Material and Methods: The study consists of 20 patientsdiagnosed with NEER’s 2 – part, 3- part, and 4 – part proximal humerus fracture. All the includedpatients were treated with internal locking plates. Based on the functional evaluation by Constant-Murley shoulder score and the assessment of radiological union foundation. Results: Excellentresults were obtained in 45% of the patients, a good result was seen in 25%, 20% of the patientshad fair results and the poor result was seen in 10% of the patients. The mean Constant-Murleyshoulder score that was obtained in the present study was 75.04. Conclusion: It’s concluded thatthere is a satisfactory functional outcome with the fixation of the proximal humerus fracture withlocking plates. While using the plate fixation for fracture the plate position is of the utmostimportance. Due to angular stability, the locking plates are the advantageous implants in case ofproximal humeral fracture.

Analysis of risk factors for revision in distal femoral fractures treated with lateral locking plate: a retrospective study in Chinese patients

BackgroundTo analyze the risk factors of revision operation after the treatment of distal femoral fracture with lateral locking plate (LLP).MethodsRetrospective analysis of the clinical data of 152 cases with distal femoral fracture treated in our hospital from March 2005 to March 2019. The SPSS 26.0 software (univariate analysis and logistic regression analysis) was used to analyze the general condition, fracture-related factors, operation-related factors, and construct characteristics of internal fixation.ResultsSixteen of 152 patients who were included in the study underwent revision surgery, with a revision rate 10.5%. Univariate analysis showed that there were significant differences in age, body mass index (BMI), fracture type, supracondylar involved or not, type of incision, quality of reduction, ratio of length of plate/fracture area (R1), the ratio of the length of the plate/fracture area above the condylar (R2), ratio of distance between proximal part of fracture and screw/working length of proximal plate (R3) between the two groups (P < 0.05). Logistic regression analysis showed that age [OR for age > 61.5 group is 4.900 (1.071–22.414)], fracture type [OR for A3 fracture is 8.572 (1.606–45.750), the OR for periprosthetic fracture after TKA is 9.073 (1.220–67.506)], poor reduction quality [OR is 7.663 (1.821–32.253)], and the ratio of the length of the plate/fracture area above the condylar were the possible risk factors (P < 0.05).ConclusionAge, fracture type (A3 and periprosthetic fracture after TKA), poor reduction quality, and the ratio of the length of the plate/fracture area above the condylar were the possible risk factors of the revision in distal femoral fractures treated with lateral locking plate. The appropriate application of the locking plate and operation strategy are the key to reduce the revision rate in distal femoral fractures.

Computationally efficient model for viscous damping in perforated MEMS structures

In this work an analytical model for the flow resistance for viscous air damping in a MEMS structure comprising a perforated plate in close proximity to a solid plate is developed. Such a configuration is widely used for oscillating MEMS sensors and actuators. It was shown that in addition to the resistance caused by the perforation hole and by squeeze film damping between the two plates, an additional resistance in the intermediate region caused by the redirection of the flow between the perforation hole region and the squeeze film region also has to be considered. The overall flow resistance is the sum of the flow resistance of several regions. The models for the individual regions have been derived analytically for the squeeze film damping and using numerical solutions of the Navier-Stokes equation for the perforation hole and the intermediate region. The validity of the derived damping model is limited to cases where the Knudsen number is smaller than 0.1, the porosity is smaller than 0.9 and the ratio between gap height of the two plates and the perforation hole radius is larger than 0.1 and squeeze number σ<<1 – which is typical dimensions MEMS structures. The presented model covers an extended geometry range compared to previously reported damping models.

Prospective Study of Radiological and Functional Outcome of Closed Subtrochanteric Fracture Fixation with Proximal Humerus Interlocking Plate in Adolescent Patients

Background: Subtrochanteric fractures constitute 1% in children. Subtrochanteric fractures in pediatric age defined as 10% length of total femur below the lesser trochanter. Mostly these fractures are unstable types. There are various treatment options available for the management of this fracture, depending on the age group of the patient. But there is no well-defined management for adolescent subtrochanteric fractures. Methods: This study includes five patients present to orthopedic emergency with closed subtrochanteric fracture without distal neurological deficit. Patients were managed operatively after informed consent with proximal humerus locking plate under regional anesthesia. Postoperatively patients were kept nonweight bearing with in-bed exercises. Follow-up was done at 2, 6, 12, 24, and 36 weeks. Patients were evaluated as functional and radiologically.

Biomechanical effects of screw orientation and plate profile on tibial condylar valgus osteotomy - Finite-element analysis

Tibial condylar valgus osteotomy (TCVO) is a type of open wedge high tibial osteotomy for correcting intra-articular deformities of medial knee osteoarthritis. However, there are no implant design and related biomechanical investigations specifically for TCVO. This study aims to investigate the effects of the proximal screw direction and plate profile on the biomechanical behaviors of the TCVO construct. Based on computed tomography images, the tibia model with TCVO was simulated. Four variations (straight and contoured plate profile × convergent and divergent proximal screw direction) with two loading conditions (compressive loads and torsional load) were compared by finite-element method. Fracture risk and construct stability were chosen as the comparison indices. For both loading conditions, the fracture risk of screw, plate and bone was the lowest in straight plate with divergent screw direction (SD), while contoured plate with convergent screw direction (CC) was the highest. Similar results were found in construct stability, SD allowed the smallest micromotions of the L-shaped opening gap, but CC allowed the highest. Divergent screw direction can decrease fracture risk of all components and provide better construct stability, while contoured plate profile seems like to have converse effects. If stability is the major concern, straight plate with divergent screw is recommended for patients with heavy load demands. Contoured plate may be suitable for skinny patients that can reduce the soft tissue irritation.

Medial minimally invasive helical plate osteosynthesis of the distal femur – a new technique

IntroductionThe goal of this study was to evaluate distal femoral minimally invasive plate osteosynthesis (MIPO) from a distal medial approach by use of a pre-bent helical implant. Material & MethodsA total of 18 lower extremities was evaluated. A 29.6 cm steel plate was constructed and pre-bent on bone specimens with a torsion of 55.7° A 5 cm incision was performed from the tip of the medial epicondyle alongside its centre in a proximal direction. The medial border of the vastus medialis was retracted anteriorly. The level of the proximal skin incision was determined using the length of the pre-bent plates. The proximal incision was performed at a length of 4 cm at the described height at a line between the lateral epicondyle and the tip of the greater trochanter. A raspatory was advanced beneath the vastus medialis in a proximal direction to create an extraperiosteal tunnel for plate insertion. The plate was fixed to the bone at its proximal and distal portion via screws. Following dissection, the distance between the nearest perforator to the proximal plate end was evaluated. The vertical distances between the medial border of the plate and the femoral artery and femoral nerve were measured at the level of the proximal plate end and at the level of the proximal margin of the vastoadductor membrane. ResultsThe most proximal perforating artery was located at a mean distance of 20.15 mm starting from the proximal plate margin. The mean interval between the medial border of the plate at the level of its proximal tip and the femoral artery was 51.9 mm. The average distance between the femoral nerve and the medial border of the proximal part of the plate was 42.3 mm. Regarding the interval between the medial border of the plate and the femoral artery, this was at a mean of 40.5 mm at the level of the proximal margin of the vastoadductor membrane. During dissection, none of the specimens showed any lesions of the adjacent anatomical characteristics. ConclusionOur results indicate MIPO of the distal femur from a medial approach as a safe technique.

Failure of the proximal locking compression plate in treatment of trochanteric femoral fractures

Treatment of proximal femoral fractures constantly draw attention of trauma surgeons because of their greater incidence. Last 10 years, shows the prevalence of intramedullary techniques, however plate osteosynthesis with proximal locking plate is still quite common in everyday practice.Objective: to conduct a retrospective analysis of treatment results of patients with proximal femoral fractures operated with locking proximal femoral plate and to identify the main mechanisms causing the high rate of unsatisfactory results. Methods: the study included 21 patients (mean age (65 ± 12) years) with fractures 31А2 and 31А3 according to the AO classification, that undergone osteosynthesis with proximal femoral LCP plate. Mean follow-up period was 7.5 months after surgery.Results: the absence of displacement and initial consolidation of the fracture was achieved in 17 of 21 patients (80.9 %). The average time of union was 6 months. Unsatisfactory results of treatment were observed in 4 cases (19.1 %). All of them were associated with fracture of the plate and nonunion of bone fragments. The fracture of the plate occurred at the level of the distal 7.3 mm locking hole in 8–9 months after the surgical intervention. In all this cases the revision surgery- implantation of proximal femoral antirotational nail (PFNA) was performed. In our opinion, such a large number of unsatisfactory results associated with excessive rigidity and an undesirable concentration of load. Conclusions: usage of proximal plates with angular stability of the screws is not always effective for the treatment of unstable fractures of the proximal femur. The high frequency of unsatisfactory results that required re-osteosynthesis with the PFNA, indicates the need for careful preoperative planning and selection of stabilization method for proximal femoral fracture treatment.

Is the proximity of external fixator pins to eventual definitive fixation implants related to the risk of deep infection in the staged management of tibial pilon fractures?

IntroductionIn the staged management of tibial pilon fractures, overlap between definitive internal fixation and external fixation pin sites has been investigated as a risk factor for infection with equivocal conclusions. Our aim was to determine if overlap or proximity of definitive internal fixation to external fixation pin sites influences the risk of deep infection. Patients and methodsWe reviewed 280 AO/OTA 43B or 43C type distal tibia fractures in 277 patients at two level-one trauma centers. Patients underwent staged management using early temporizing external fixation followed by definitive open reduction and plate fixation. Primary outcome was the association between pin site overlap and the development of deep infection. Secondary outcome was the relationship between development of deep infection and the distance from pin site to definitive fixation. ResultsThe average duration between external fixation and definitive internal fixation was 14 days. 24% of fractures developed deep infection requiring surgical intervention. There was no association between pin site overlap and the development of deep infection (p = 0.18). There was no relationship between infection and the distance between proximal plate extent and pin site (p = 0.13). DiscussionWe identified no association between pin site overlap and the development of deep infection. We suggest that temporizing external fixation pins should be placed so as to obtain optimal stability of the construct with lesser emphasis on aiming to be absolutely outside the zone of future fixation. Level of evidenceLevel III Therapeutic Retrospective Comparative study.

Accuracy of removable partial denture framework fabricated by casting with a 3D printed pattern and selective laser sintering

PurposeThe present study aimed to compare the accuracy of removable partial denture (RPD) frameworks fabricated by 3D-printed pattern casting and those fabricated by selective laser sintering (SLS). MethodsA partially edentulous mandibular model was used for the simulation model. Scanning of the model was performed using a dental scanner. The framework was designed by using CAD software. The 3D-printed resin pattern was formed using a 3D printer and casting was performed (AM-Cast framework), and a direct metal laser sintering machine was used for the framework of SLS (SLS framework). 3D scanning of fabricated two types of framework were performed, and these data were overlapped with design data. Fabrication accuracy was verified using the Mann–Whitney U test to compare the discrepancy between the AM-Cast and SLS frameworks. ResultsThe range of differences for the AM-Cast and SLS framework were −0.185±0.138 to 0.352±0.143mm and −0.166±0.009 to 0.123±0.009mm, respectively. Statistically significant differences were observed at the rests, proximal plates, connectors, and clasp arms. Regarding the rests, both lateral and medial displacement in the two types framework was observed in relation to the design data. Large lateral discrepancies of the connectors were observed at the joining area on the tooth-supported side of the lingual bar for the AM-Cast framework. Localized discrepancies were observed at the center of the lingual bar for the SLS framework. ConclusionThe accuracies of RPD frameworks fabricated by AM-Cast and SLS differ depending on the specific structural component of the RPD.

Importance of locking plate positioning in proximal humeral fractures as predicted by computer simulations.

Multifragmented proximal humeral fractures frequently require operative fixation. The locking plates commonly used are often placed relative to the greater tuberosity, however no quantitative data exists regarding the effect of positional changes. The aim of the study was to establish the effects from variations in proximal-distal PHILOS humeral plate positioning on predicted fixation failure risk. Twenty-one left-sided low-density virtual humeri models were created with a simulation framework from CT data of elderly donors and osteotomized to mimic an unstable three-part malreduced AO/OTA 11-B3.2 fracture with medial comminution. A PHILOS plate with either four or six proximal screws was used for fixation. Both configurations were modelled with plate repositioning 2 and 4 mm distally and proximally to its baseline position. Applying a validated computational model, three physiological loading situations were simulated and fixation failure predicted using average strain around the proximal screws-an outcome established as a surrogate for cycles to failure. Varying the craniocaudal plate position affected the peri-implant strain for both four and six-screw configurations. Even though significant changes were seen only in the latter, all tests suggested that more proximal plate positioning results in decreased peri-screw strains whereas distalizing creates increases in strain. These results suggest that even a small distal PHILOS plate malpositioning may reduce fixation stability. Plate distalization increases the probability of being unable to insert all screws within the humeral head, which dramatically increases the forces acting on the remaining screws. Proximal plate shifting may be beneficial, especially for constructs employing calcar screws. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

A practical, quantitative electrostatics experiment

An electrostatics experiment is presented that is practical, affordable, and quantitative. The equipment required is readily available and relatively inexpensive. The experiment relies on the electrostatic induction that results from a charged insulative plate in proximity to a conductive sphere. The experiment yields accesible results (a) under a variety of environmental conditions and results that (b) allow for quantitative analyses. These two characteristics distinguish it from most other simple electrostatics experiments. It is intended for college introductory physics students.

Low complication rates in Minimally Invasive Plate Osteosynthesis (MIPO) for proximal humeral fractures at 5 years of follow-up

Introduction: Purpose of this study was to analyse the medium term follow-up of minimally invasive plate osteosynthesis (MIPO) for proximal humeral fractures in terms of postoperative shoulder function, radiological outcome and complications.Methods: 76 consecutive patients with unstable proximal humeral fractures were treated using locking plate with a minimally invasive antero-lateral approach in two surgical centers. Constant score and radiographic evaluation of 74 patients were available at mean follow up of 5 years (minimum 4 years).Results: Mean Constant score was 74 (range to 28–100). Results were comparable in the two centers. Younger patients registered significantly higher scores (p < 0.05). 20 patients (27%) developed complications. Subacromial impingement occurred in 16,2% of cases for varus malreduction (6,7%) and for too proximal plate positioning (9,5%). Primary screws perforation (2,7%), secondary perforation due to cut-out (1,4%), avascular necrosis (AVN) of humeral head (1,4%), partial resorption of greater tuberosity (2,7%), secondary displacement of the greater tuberosity (2,7%) and stiffness (2,7%) were observed.Discussion and conclusions: Even at a medium term follow-up, MIPO for proximal humeral fractures ensured good and reproducible results for most common pattern of fractures. Major complications were lower respect to open procedures, because of soft tissue, deltoid muscle and circumflex vessels sparing.

Plate fixation in periprosthetic femur fractures Vancouver type B1: preliminary report of macroscopic evaluation of the cement mantle and short literature review.

The goal of our preliminary report is to investigate hip stem stability and intra-operative cement mantle integrity after screw insertion in plate fixation of periprosthetic Vancouver B1 femur fractures. From a cohort of 50 patients with a periprosthetic femur fracture treated in our department from February 2012 until February 2017, we included in our study patients with a periprostethic Vancouver B1 femoral fracture in cemented hip arthroplasty and hemiarthroplasty, operated with ORIF using a 4.5/5.0 LCP Proximal Femoral Hook Plate ® (Synthes, Switzerland) with at least one screw perforating the cement mantle. Anteroposterior and lateral femur views and pelvis X-rays were performed preoperatively. The stability of the hip implant and the cemented mantle integrity was evaluated intra-operatively in a macroscopic way and with a post-operative X-ray in anteroposterior and lateral views. Only 7 patients satisfied the inclusion criteria; no lesion/break of the cement mantle occurred intra-operatively at any step during drilling or screw insertion, also confirmed with C-arm assessment. No cases of stem mobilization were found and cement mantle integrity was maintained in every case. Insertion of screws around a cemented stem for plate fixation in periprosthetic femur fractures Vancouver type B1 could be considered a safe procedure. However, further and more extended studies are necessary for proving additional knowledge at the evaluation of the cement mantle in osteosynthesis procedures. (www.actabiomedica.it)

Analysis of proximal plating versus intramedullary nailing in the treatment of extra-articular proximal tibial fractures

Extraarticular fractures of proximal tibia has been a challenging situation to most of the surgeons today. Treatment of these injuries is extremely challenging because of the inherent unstable fracture region, difficult reduction & fixation and severely compromised blood supply at the region. For the past decades, closed reduction and minimally invasive plating and intramedullary nailing have both become widely used treatment modalities for proximal and distal tibial metaphyseal fractures. This study was performed to compare the functional and radiological results of locking compression plateosteosynthesis over intramedullary nailing. This randomized prospective clinical study was conducted on 29 patients with a closed extra-articular fracture of the proximal tibia treated with minimally invasive percutaneous plate osteosynthesis (MIPPO) or intramedullary nailing by Tibia interlocking nail at a tertiary trauma center. Postoperative hospital stay, time to full weight-bearing, and union time were significantly less in the IMN group than in the PTP group, but there was no clear advantage of either technique in terms of operative time, infection rate, range of motion of the knee, or degrees of malunion and nonunion. Both implants have shown promising results in extra-articular proximal tibial fractures, and provide rigid fixation that prevents secondary fracture collapse.

Functional and radiological outcome of proximal femoral locking compression plates in the treatment of unstable trochanteric fractures

Introduction Intertrochanteric femoral fracture is extracapsular fracture of the proximal femur between the greater and lesser trochanters. They represent about 50% of all hip fractures. Considerable complications such as pulmonary embolism, deep venous thrombosis, and pneumonia are frequently seen with these fractures mainly due to prolonged immobilization and specifically in elderly patients. These fractures can be categorized into stable and unstable according to the bony construct displacement after a fracture. Approximately 35–40% will be classified as unstable three-part and four-part fractures; unstable fractures are difficult to manage with dynamic hip screw alone and are technically much more challenging and the treatment is more controversial. Patients and methods During the period from 1 July 2016 till 1 February 2017, 44 patients with unstable trochanteric fractures AO A2 and A3 who were admitted in the Causality Department in Kasralainy Hospital, Cairo University were randomly selected in our study to be treated by fixation with proximal femoral locking compression plate according to the standardized protocol. Results Patient demographics: 28 women and 16 men were included with a mean age of 61.75 years (SD 8.7); eight patients were diabetic; four patients were hypertensive, and three were cardiac. The total hospital stay was a mean of 8.95 days, mean preoperative period was 4.44 days, and the mean postoperative period was a mean of 4.73 days (SD 1.16).The mean operative time was 106 min; the mean blood loss intraoperative was 308 ml; postoperative infection was three (6.8%) cases; and all of them resolved with a single session of debridement. One case of deep venous thrombosis (DVT) was treated by conservative measures and four cases of varus malunion with no functional deficit. The mean time for fracture union was 17.9 weeks and the mean time till weight-bearing was 12 weeks. Mean harris hip score (HHS) at 6 months was 62.3 which is fair and 81.2 at 12 months which is good. Conclusion Proximal femoral locking compression plate was an effective treatment for unstable trochanteric fracture in terms of time to full weight-bearing. It can be used in these fractures with good functional outcomes and low complication rates. Level of Evidence: Level II randomized, prospective trial.

Modified lateral approach versus deltopectoral approach in treatment of elderly proximal humeral fractures

Objective To compare the clinical effects of proximal humerus locking compression plate (PHILOS) through the modified lateral approach and deltopectoral approach in the treatment of senile proximal humeral fractures. Methods From May 2012 to February 2015, 40 patients with fresh senile proximal humeral fractures were treated in our department. There were 18 males and 22 females. According to the surgical approach they were divided into 2 groups: conventional group (the deltopectoral approach) of 20 patients and minimally invasive group (the modified lateral approach) of 20 patients. They were treated by PHILOS fixation. The intraoperative blood loss, operation time, intraoperative and postoperative complications, Constant scores at 1 month, 3 months and the last follow-up, as well as X-ray films of the affected shoulder at follow-up, were analyzed and compared between the 2 groups. Results All the 40 cases were follow-up for an average of 16 months (range, 7 to 33 months). No incision infection occurred and bony union was all achieved. The minimally invasive group were significantly better than the conventional group in blood loss, operation time, incision length and union time (P 0.05). In the conventional group, cephalic vein injury occurred in 2 cases. Conclusion The modified lateral approach applied in the treatment of proximal humeral fractures has the advantages of less trauma and quicker recovery, which provides a good alternative for senile proximal humeral fractures. Key words: Shoulder joint; Fracture fixation,internal; Surgical procedures,minimally invasive; Approach

Proximal femur locking plate fixation for the treatment of unstable femoral intertrochanteric fractures in elderly patients

Objective To explore the efficacy of proximal femur locking plate(PFLP) for the treatment of unstable femoral intertrochanteric fractures in elderly patients. Methods Data of 120 cases of patients with unstable femoral intertrochanteric fractures who were treated by PFLP were retrospectively analyzed. There were 56 males and 64 were females, aging from 62 to 78 year-old (average, 69.4 year-old). 85 cases were left hip, and 35 cases right hip. According to AO fracture classification, there were 12 cases of A2.2, 23 A2.3, 34 A3.1, 29 A3.2, and 22 A3.3. According to Evans intertrochanteric fractures classification: there were 93 cases of type III, 19 type IV, and 8 type V. Operation time, length of hospital stay, fracture healing time, postoperative complications and hip joint Harris scores were recorded. Results All patients were followed up for 8-14 months (average, 12.4 months). Their operating time were 51-80 min (average, 63.1 min); X-ray exposure were 8-15 times (average, 11.6 times); intraoperative blood loss were 70-120 ml (average, 92.7 ml); postoperative drainage volume were 50-100 ml (average, 61.7 ml), and length of hospital stay were 7-14 d (average, 10.2 days). The healing time ranged from 12 to 32 weeks (20.4 weeks average). 14 cases had delayed union, and healing time was 8-10 months. In addition, 4 cases had deep vein thrombosis (after thrombolysis therapy the vein was recanalized); 2 had internal fixation broken, who were then treated with PFNA II, and bone healed after 6 months; 5 had hip varus, who were then treated via hip replacement, and no hip prosthesis fracture were found. No other complications occurred in the remaining patients. At the latest follow-up, according to Harris hip score: there were 38 cases with excellent results, 71 good, 9 fair, and 2 poor, and the rate of excellent and good was 90.8% (109/120). Conclusion PFLP for the treatment of unstable femoral intertrochanteric fractures has advantages of less invasion, less complication, reliable fixation and high fracture healing rate, thus it is suitable for unstable intertrochanteric fractures in elderly patients. Key words: Aged; Hip; Fractures, bone; Fracture fixation, internal

THE EFFECT OF TWO MANDIBULAR CLASS I REMOVABLE PARTIAL DENTURE DESIGNS ON THE PERIODONTAL HEALTH OF THE ABUTMENT TEETH: A RANDOMIZED SPLIT-MOUTH CLINICAL TRIAL

The aim of this study was to assess the effect of RPI direct retainer designs in mandibular Kennedy’s class I removable partial denture cases, on the periodontal conditions of their abutment teeth.Materials and methods: A total of 10 systemically healthy Patients were selected with mandibular Kennedy class I with symmetrical healthy periodontium at first premolar abutments split mouth mandibular class I removable partial denture designs RPI, I-bar (Rest, proximal plate and I bar) in one side (side A) and a modified RPI clasp assembly (Rest, proximal plate connected by lingual bracing arm to the rest and I Bar) in other side (side B) were constructed. Clinical evaluation(gingival index, pocket depth and clinical attachment loss) and recording of GCF levels of Interlukin1s IL1 –β using ELISA were carried out for all patients at base line (time of denture insertion), 3 months and 6 months after denture insertion at mandibular free end saddle abutments.Results: A statistically significant increase in the mean IL-1s levels after 3 months with further significant increase after 6 months was recorded in both sides (P ≤ 0.05) further, side B showed a statistically increased IL-β levels compared to side A. Regarding clinical parameters, side B showed a statistical significant increase at 6 months compared to side A regarding PD with no significant difference between the 2 sides at 3 months ,as for CAL and GI, although side B showed an increased readings in 6 months and 3 months compared to side A, a non significant difference was recorded between the 2 sides, as well, a non significant change in GI and CAL was recorded in both sides over the study period .Conclusion: within the limitation of our study, the modified RPI clasp induced increasing of proinflammatory cytokines IL- 1s levels in GCF compared conventional RPI clasp assembly. Both Clasp designs have an effect on periodontal health of free end saddle’s partial denture abutments.

An anatomical study of plate-rod fixation in feline tibiae.

To investigate the feasibility of placing bi-cortical cortex (B-cort) or mono-cortical locking screws (M-lock) in a plate-rod construct applied to the feline tibia in combination with different intramedullary (IM) pins. Twenty-four feline tibiae of cats were divided into 4 groups, corresponding to IM pin sizes filling approximately 30% (1.0 mm), 40% (1.4 mm), 45% (1.6 mm), and 50% (1.8 mm) of the medullary canal. Computed tomography (CT) was performed to trace potential screw trajectories in each group. A 12-hole, 2.4 mm locking compression plate was then applied on the medial aspect of the tibia. M-lock and B-cort screws were inserted subsequently in each plate hole. Success rates of screw insertion based on CT analysis and cadaveric simulation were compared with screw type, IM pin diameter, and anatomic location as variables. Screw insertion rates were underestimated on CT compared to cadaveric specimens. During cadaveric simulation, B-cort screws could be inserted in all specimens in the 3 most proximal plate holes and in at least 1 of the 3 distal plate holes. The smallest pin size (30%) allowed placement of a greater number of B-cort screws (P < .05) compared to other pins. Fewer B-cort screws could be inserted in the distal diaphyseal region (P < .05) compared to other regions. A total of 99.3% of M-lock screws could be inserted regardless of IMP size. Plate rod constructs can include bicortical screws in the proximal and distal metaphysis, and monocortical screws in the diaphysis, combined with an IM pin filling up to 50% of the medullary canal.