1.The effect of the digital manufacturing technique of cantilevered implant-supported frameworks on abutment screw preload
Shahad Mohammmed ALTUWAIJRI ; Hanan Nejer ALOTAIBI ; Talal Mughaileth ALNASSAR
The Journal of Advanced Prosthodontics 2022;14(1):22-31
PURPOSE:
The purpose of this study was to investigate the misfit and screw preload at the implant abutment connection of implant supported fixed dental prosthesis with cantilever (ICFDP) manufactured using different digital manufacturing techniques and to compare the screw preload before and after cyclic loading.
MATERIALS AND METHODS:
Mandibular jaw model with four intra-foraminal implants was scanned using digital scanner. Stereolithography file was used to design a framework with nonengaging (NE) abutments and 10 mm cantilever distal to one terminal implant. Five frameworks were constructed using combined digital-conventional techniques (CAD-cast), and five frameworks were constructed using three-dimensional printing (3DP). Additional CAD-cast framework was constructed in a way that ensures passive fit (PF) to use as control. Scanning electron microscope (SEM) measured the implant abutment connection misfit. Sixty screws were used on the corresponding frameworks. Screws were torqued and pre-cyclic loading reverse torque value (RTV) was recorded. Frameworks were subjected to 200,000 loading cycles with a loading point 9 mm from the center of terminal implants adjacent to the cantilever and post-cyclic loading RTVs were recorded.
RESULTS:
Microscopic readings showed significant differences between frameworks. PF demonstrated the lowest measurements of 16.04 (2.6) µm while CAD-cast demonstrated the highest measurements of 29.2 (3.1) µm. In all groups, RTVs were significantly lower than the applied torque. Post-cyclic loading RTV was significantly lower than pre-cyclic loading RTV in PF and 3DP frameworks. Differences in RTVs between the three manufacturing techniques were insignificant.
CONCLUSION
Although CAD-cast and three-dimensionally printed (3DP) both produce frameworks with clinically acceptable misfit, 3DP might not be the technique of choice for maintaining screw’s preload stability under an aggressive loading situation.
2.Middle East respiratory syndrome coronavirus in pediatrics: a report of seven cases from Saudi Arabia.
Sarah H ALFARAJ ; Jaffar A AL-TAWFIQ ; Talal A ALTUWAIJRI ; Ziad A MEMISH
Frontiers of Medicine 2019;13(1):126-130
Infection with Middle East respiratory syndrome coronavirus (MERS-CoV) emerged in 2012 as an important respiratory disease with high fatality rates of 40%-60%. Despite the increased number of cases over subsequent years, the number of pediatric cases remained low. A review of studies conducted from June 2012 to April 19, 2016 reported 31 pediatric MERS-CoV cases. In this paper, we present the clinical and laboratory features of seven patients with pediatric MERS. Five patients had no underlying medical illnesses, and three patients were asymptomatic. Of the seven cases, four (57%) patients sought medical advice within 1-7 days from the onset of symptoms. The three other patients (43%) were asymptomatic and were in contact with patients with confirmed diagnosis of MERS-CoV. The most common presenting symptoms were fever (57%), cough (14%), shortness of breath (14%), vomiting (28%), and diarrhea (28%). Two (28.6%) patients had platelet counts of < 150 × 10/L, and one patient had an underlying end-stage renal disease. The remaining patients presented with normal blood count, liver function, and urea and creatinine levels. The documented MERS-CoV Ct values were 32-38 for four of the seven cases. Two patients (28.6%) had abnormal chest radiographic findings of bilateral infiltration. One patient (14.3%) required ventilator support, and two patients (28.6%) required oxygen supplementation. All the seven patients were discharged without complications.
Adolescent
;
Child
;
Coronavirus Infections
;
diagnosis
;
physiopathology
;
Diarrhea
;
etiology
;
Dyspnea
;
etiology
;
Female
;
Fever
;
etiology
;
Humans
;
Infant
;
Lung
;
diagnostic imaging
;
Male
;
Middle East Respiratory Syndrome Coronavirus
;
genetics
;
Pleural Effusion
;
diagnostic imaging
;
Radiography, Thoracic
;
Saudi Arabia