Now my son very attached to pacifier. He cries when i took it especially when he bored or sleepy. So worry about it.. is it ok to let him use it for prolonged time?

Prolonged and frequent use of pacifier may cause delay in speech, affect incoming teeth and increase risk of ear infection. Try to restrict their using to only near sleeping time. My son used to be a pacifier addict. We tried to hide the pacifier away and distract him with other activities during the day! However, you might wana wean him off when he's 3-4yo, to prevent further dental problems (eg. upper teeth tip forward and etc).