| Author | Year | Ferrule Design | Results |
| Figueiredo et al. [24] | 2018 | - No ferrule - Full 2 mm ferrule - 2 mm ferrule only from the buccal side - 2 mm ferrule from the lingual side - 2 mm ferrule from the lingual and buccal sides |
The ferrule design does not affect the biomechanical behavior of the incisors after endodontic treatment, that were restored using fiber posts, under cyclic loading. |
| Dua et al. [25] | 2016 | - No ferrule - Full 2 mm ferrule - 2 mm ferrule only from the buccal side - 2 mm ferrule from the lingual side 1) from the lingual side 2) – 2 mm ferrule from the lingual and buccal sides with undercuts from the approximal sides. |
The maximum resistance to fractures was achieved in the group with a full ferrule and in the group with a buccal ferule. |
| Haralur et al. [26] | 2018 | 1) 1) Full 2 mm ferrule 2) 2) 2 mm ferrule on the buccal side and 0.5 mm on the palatal side 3) 3) 2 mm ferrule from the palatal side and 0.5 mm from the buccal side 4) 4) 2 mm ferrule on the lingual and buccal sides, with a 0.5 mm ferrule on the approximal sides 5) 5) No ferrule |
1) 1) The presence of a 2 mm ferrule significantly improves fracture resistance 2) 2) Teeth with an incomplete ferrule are much more effective in resisting the destruction compared to its complete absence 3) 3) The absence of a ferule in the proximal area, both in the area of the front teeth and in the area of premolars, does not significantly affect the resistance to fracture 4) The absence of a ferule on the lingual side significantly reduces resistance to fractures. |
| Kar [27] | 2017 | 1) Ferule is absent 2) 1 mm ferule 3) 2 mm ferule 4) 3 mm ferule |
Increasing the length of the ferrule can significantly increase fracture resistance. |
| Meng [28] | 2018 | 1) 1) - 0 mm ferrule with buccal and 2 mm from the lingual side 2) 2) - 1 mm ferrule from the buccal side and 3 mm from the lingual side 3) - 2 mm ferrule from the buccal side and 4 mm from the lingual side |
Resistance to fractures in endodontically treated teeth with a high inclined ferrule was the highest, regardless of the type of load. |
| Muangamphan [29] | 2015 | 1) - Full ferule 2) - Ferrul from the buccal side, from the palatal side and from the mesial side. 3) - Ferrul from the buccal side, from the palatal side. 4) - Ferrul from the palatal side 5) - Ferrul from the buccal side 6) - Ferrul is absent |
Incomplete ferrule may affect fracture resistance in the restoration of endodontically treated anterior teeth |
| Zhang [30] | 2014 | Group 1 (as a negative control): 0 mm from the buccal side and 0 mm from the palatal side. Group 2: 1 mm from the buccal side and 0 mm from the palatal side. Group 3: 2 mm from the buccal side and 0 mm from the palatine side. Group 4: 0 mm from the buccal side and 1 mm from the palatal side. Group 5: 0 mm from the buccal side and 2 mm from the palatal side. Group 6 (as a positive control): 2 mm from the buccal side and 2 mm from the palatal side. |
The height of the ferrule on the palatal side can effectively protect the surface of the build-up border, preventing damage from expanding the layer of adhesive cement |