To explore the technology of combination with computed tomography (CT), computer aided design (CAD), finite element analysis (FEA), and Selective Laser Melting (SLM) in manufacturing a titanium custom-fitting surgical guide well matched with the patient mandible in order to realize mold-free manufacturing.

A model of a custom-fitting surgical guide was built by CT scanning machine and Solidworks software, and then the model was imported into Ansys software to carry out simulation analysis with nonlinear contact method. Finally, the model above was imported to SLM molding equipment, the titanium custom-fitting surgical guide was proposed via titanium powder melted with layer by layer using a high-speed scanning galvanometer.

The maximum equivalent stress of the mandible and surgical guide was distributed uniformly and reasonably, the titanium custom-fitting surgical guides formed by SLM molding equipment provided high accuracy and high density.

The combination of CT, CAD, FEA, SLM technology can fulfill mold-free manufacturing of surgical guides and the manufacturing cycle is shorten as well.

To evaluate the effect of three different resin cement on fracture strength of cemented machinable IPS e.max CAD specimens and provide guides for clinical luting procedure.

Sixty human molars were collected, and occlusal enamel were removed; IPS e. max CAD blocks were processed into plate-shape and etched with 9.5% hydrofluoric acid. All specimens were randomly divided into three groups (n = 20) and received there different luting treatments, (group A: Multilink^® N+ Monobonds-S, group B: RelyX^TM Ultimate+ Scotchbond^TM adhesive, group C: RelyX^TM Unicem 2). Then each group were divided into two sub-groups (group 1: the control group, group 2 received thermal cycling). Fracture load was measured with a universal testing machine. The results were analyzed by two-way ANOVA and LSD test.

Fracture load of each group were A1(1763 ± 128)N、A2(1563 ± 115)N、B1(1861 ±135)N、B2(1676 ± 137)N、C1(1446 ± 153)N、C2(1038 ± 95)N. Significant differences of fracture load were observed among all groups (F = 52.279, P＜0.001). Resin cement (F = 94.104, P＜0.001) and thermal cycling (F = 63.818, P＜0.001) affected the fracture load significantly. LSD test showed that significant differences of fracture load were observed among group A, B and C (P＜0.05). Group B illustrated the highest fracture load where as group C demonstrated the lowest one.

Resin cement that treats the ceramic and dentin surface simultaneously will strengthen the fracture load of the glass ceramic. Thermal cycling will reduce the fracture strength of cemented glass ceramic.