Final answer:
Self-etch adhesives have disadvantages including lower bond strength, potentially poor smear layer removal, less effective etching on dentin and enamel, risk of post-operative sensitivity, technique sensitivity, and limited shelf life after opening.
Step-by-step explanation:
The disadvantages of self-etch adhesives in dentistry are several. First, they have a lower bond strength compared to total-etch systems, which can affect the longevity of dental restorations. Secondly, self-etch systems may not be as effective in removing the smear layer, leading to a less ideal bonding surface and potentially compromising the seal of the restoration. Furthermore, some self-etch adhesives may not penetrate as well into the dentin, thus limiting their ability to create strong micromechanical retention. Additionally, their acidity can sometimes be too mild to adequately etch harder tooth substrates like enamel, requiring a separate etching step anyway. Clinicians also need to be wary of technique sensitivity and the specific manufacturer's instructions, as improper use can further hamper performance. In some cases, self-etch adhesives can lead to post-operative sensitivity if the bond is not completely sealed. Lastly, self-etch adhesives have a limited shelf life once opened, which can affect their performance if used beyond this period.