First, you need to know what kind of brushing experience that you are looking for. Some brushes are designed to be gentle on sensitive gums while sacrificing some of the deep clean that is associated with electric toothbrushes.
In cases like this, a combination of toothpaste whitening power and dedicated brushing can make up for the lack of deep brushing. Products to cover bad breath should never be a substitute for brushing.
If you do go the route of trying to use products to cover bad breath instead of real brushing, you will find that you will be far more prone to cavities and other problems than if you had taken the time to brush your teeth daily. Dental gums and other tooth "cleaning" products should also never be used to fully supplement brushing. These products are designed as a supplement to keep teeth clean between brushings.
If your gums are not quite as sensitive, you can select Braun Oral-B brush heads that are stiffer and rougher on germs, plaque and gums. These style of replacement toothbrush heads are designed to prevent the need for toothpaste whitening kits.
The primary concern that you will need to keep in mind when you are selecting your replacement toothbrush heads is that the heads must match the toothbrush. Only Braun Oral-B Brush heads will work within a Braun electric toothbrush. While this may seem to limit you selection, companies like Braun work hard to ensure that you have as many choices possible when you are trying to find the perfect replacement toothbrush heads for your electric toothbrush.