Complex sentence: Other putative mechanisms of methadone-related tooth decay include craving for carbohydrates related to opioids, poor dental care and general decrease in personal hygiene due to these factors combined with sedation have causing extensive dental damage.
Split into simpler sentences: Other putative mechanisms of methadone-related tooth decay include craving for carbohydrates related to opioids, poor dental care, and general decrease in personal hygiene. These factors combined with sedation have causing extensive dental damage.