Effect of Framework's Manufacturing Technique on Screw's Preload of Implant Supported Prosthesis

Background

Implant supported prosthesis is a common treatment modality. Nowadays, new manufacturing techniques are available to fabricate them.

Aims

To evaluate the effect of different manufacturing techniques of implant supported frameworks (ISF) on the preload of abutment's screws.

Materials and Methods

A mandibular edentulous acrylic model with four dental implants temporarily stabilized in the interforaminal area was used. One ISF was fabricated using the conventional technique; implants were removed from the model and reassembled into the framework; this framework served as the passively fitting framework (PF). Three additional frameworks were constructed: conventional cast framework (CF), milled framework (MF) and 3D-printed framework (3D-PF). The gap between the frameworks and the neck of the implants were recorded in microns using a digital microscope. A tightening torque (TT) of 35 N·cm was applied to all the four abutments' screws and the screw's preload was recorded using two methods, by strain gauges (SGs) that were attached to the neck of each implant and fed into a stain book in microstrain (μɛ) and by removal torque (RT) using a digital torque meter.

Results

The frameworks' gap means from the lowest to the highest were PF, CF, 3D-PF, and MF. The RT was significantly lower than the TT in all frameworks (P ≤ 0.05). One-way analysis of variance (ANOVA) revealed that the PF had the lowest RT, while the CF and the 3DPF both had the highest RT, and those differences were found to be statistically significantly (P ≤ 0.05). When preload of the frameworks was recorded by SGs, one-way ANOVA revealed that PF had the highest preload value, while both 3D-PF and MF had the lowest preload values, those differences were also found to be statistically significant (P ≤ 0.05).

Conclusion

The fabrication of implant-supported frameworks using milling or selective laser melting computer aided design/computer-aided manufacturing technologies did not necessarily enhance the screw's preload. This lack of enhancement could be attributed to the great amount of marginal gap in the frameworks fabricated by both techniques.

Chronic abdominal pain after laparoscopic hernia repair due to mesh graft migration to the cecum: a case report

Background

Hernia repair with mesh graft is one of the most common procedures in general surgery. Mesh graft repair is the treatment of choice for umbilical and periumbilical hernias to minimize recurrence. One of the rare but serious complications is mesh graft migration to viscus. These complications can occur months to years after repair and their diagnosis can be challenging as they may present as vague abdominal pain only.

Case presentation

A 74-year-old gentleman with multiple medical comorbidities was diagnosed with a para-umbilical hernia after which he underwent a laparoscopic hernia repair at our hospital using a mesh graft with no complications. On postoperative day 10, he presented to the emergency room (ER) complaining of colicky abdominal pain in the right iliac fossa for 1 day associated with diarrhea. A Computed Tomography (CT) scan of the abdomen and pelvis showed diffuse wall thickening of the cecum and terminal ileum with small free air worrisome for perforation. The decision was made in the ER to discharge him home on antibiotics. The patient then returned back multiple times to the ER for the same complaint along with bleeding per rectum for which he underwent further investigations. Months later, the patient presented again with the same symptoms. A CT scan revealed recurrence of a periumbilical hernia and thickening of the medial wall of the cecum with mesh graft material. The patient was then taken to surgery and intra-operative findings revealed migration of almost 50% of the mesh graft size to the cecum and part of the mesh graft was eroding the distal part of ileum just proximal to the ileocecal junction. Adhesolysis and limited right hemicolectomy with ileocolic anastomosis was done. The patient had an uneventful recovery after revisions surgery without any perioperative complications. He was discharged home on postoperative readmission day 5 and followed up at 2 weeks and 3 months without any delayed complications or subjective complaints.

Conclusion

It is important to consider mesh graft migration to viscus as a cause of persistent abdominal pain and bleeding per rectum irrespective of the time of presentation post hernia repair.