Adventist Teaching: Yes
Biblical Teaching: No
In Adventist theology, by way of their prophetess, Ellen G. White, perfect obedience to the Law of God is required in order to be saved. There are many reasons for this, one of which is their understanding of the nature of man.
After explaining that we should not use grace as a license to sin (Romans 6:1), the Apostle Paul then explains in the next chapter the war and struggle that the Christian begins to experience. Prior to being regenerated, Believers do not feel conviction of sin. But upon the Holy Spirit indwelling a person, the new nature of the man begins warring with the old, fleshly man (Romans 7:14-20). Paul even goes so far as to recognize that he—as a believer, still living in his fallen flesh—does what the new man hates! (Romans 7:15) This war will happen until Believers bodies are glorified resulting in no longer having a propensity to sin. In the meantime—we wage war—picking up our cross daily (Matthew 16:24) and following Christ, seeking to put to death the deeds in the flesh (Romans 8:13) by walking in the Spirit. Until this fallen flesh is sown a corruptible body, (1 Corinthians 15:42-3), it will not be an incorruptible body.
But in Adventist theology, they do not have a strong understanding of the spiritual aspect of reality. They don’t believe man has a spirit/soul outside of the breath of the body—the soul is a combination of the breath and the body (monism). Because of this physicalist worldview, they don’t see the spiritual aspect that is also touched by sin which causes this war inside Believers. Ellen taught (as does the SDA Bible Commentary) that the resurrected man/woman will be given a new body of new particles and your character/personality will be, from God’s memory, placed into this new body in a newly made creation. This body will be just like Adams was prior to the fall. Since Adam had the possibility of sinning it needs to be demonstrated presently that you can be trusted to not let sin enter in again. That happens now while you mankind is on probation just like Adam and Eve were.
So in their system, they have to, in this life, with the help of the Holy Spirit, get to a sinlessly perfect state, demonstrating they are worthy of Christ’s atoning benefits. They teach that mankind is on a period of probation (something scripture nowhere teaches) and must demonstrate that that they can be trusted in the New Heaven and the New Earth.
This is downstream of their pre-earth origin story around the Great Controversy which claims that Lucifer began accusing God’s Law of being tyrannical and unfair. To silence these accusations, Jesus came and kept the Law perfectly to prove that it can be done and vindicate the Law. He was the Example for mankind to see that it can be done and the Holy Spirit has been sent to now empower you to be able to do the same as Jesus. You too can silence the accusations in the Great Controversy, just like Jesus.
Those are a couple (of many) reasons why the Adventist Church teaches sinless perfectionism, contrary to passages like Ecclesiastes 7:20, 1 John 1:8 and Romans 7:14-20.