Field for multiple checkboxes for Django model 2.1

Hello, I would like to know how I can do and store in a field multiple checkboxes for my model. I tried the following:

models.py:

n_dentes = (
    ('18', '18'),
    ('17', '17'),
    ('16', '16'),
    ('15', '15'),
    ('14', '14'),
    ('13', '13'),
    ('12', '12'),
    ('11', '11'),
    ('21', '21'),
    ('22', '22'),
    ('23', '23'),
    ('24', '24'),
    ('25', '25'),
    ('26', '26'),
    ('27', '27'),
    ('28', '28'),
    ('48', '48'),
    ('47', '47'),
    ('46', '46'),
    ('45', '45'),
    ('44', '44'),
    ('43', '43'),
    ('42', '42'),
    ('41', '41'),
    ('31', '31'),
    ('32', '32'),
    ('33', '33'),
    ('34', '34'),
    ('35', '35'),
    ('36', '36'),
    ('37', '37'),
    ('38', '38'),

)
class pregao(models.Model):
    dente = MultiSelectField(_('Dente '), choices=n_dentes, default=' ', max_length=100)
    cor = models.CharField(_('Cor '), default=' ', max_length=5)
    material = models.CharField(_('Material '), choices=materiais_choices, max_length=100, default=' ')
    extra = models.TextField(_('Observações '), max_length=500, null=True, blank=True)
    data = models.DateField(default=datetime.date.today)
    preco = models.FloatField(_('Preço '), default='0')
    class Meta:
        verbose_name = 'Pregão'
        verbose_name_plural = 'Pregões'

page.html

{% for value, text in form.providers.field.choices %}
                        <div class="ui slider checkbox">
                            <input id="id_providers_{{ forloop.counter0 }}" name="{{ form.providers.name }}" type="checkbox" value="{{ value }}"{% if value in checked_providers %} checked="checked"{% endif %}>
                            <label style="width:8px;">{{ text }}</label>
                        </div>
{% endfor %}

But when rendering it all goes out of the way and I still have to go through a library, is there any other more efficient way for me to do that?