Introduction
Every animal deserves a non-traumatic occlusion free of discomfort (6). Some terms should be clarified to understand what crossbite and level bite are. Occlusion, or bite, is the term that defines the contact between maxillary and mandibular teeth in a closed mouth. Ideal occlusion is one that does not harm the individual, has an equal distribution of the mastication forces. Normal occlusion, as veterinary dentistry standards define it, implies: Incisors: maxillary ones are rostrally positioned to the mandibular ones, having contacts between the incisal tips of the lower ones and the cingula of the upper ones; Canines: mandibular ones are situated between the third upper incisor and the maxillary canine; Premolars: Maxillary and mandibular premolars do not have any contacts. The crown cusps of the mandibular ones are situated lingually next to the ones of the maxilla. The mesial cusp of the upper carnassials is localised lateral to the space between the fourth mandibular premolar and the first mandibular molar (9). Normal occlusion is known as a scissor bite. This dental interlock prevents normal rostral growth of the mandibles (1). Malocclusion defines abnormal relationships between the maxilla and mandibula. Both human dentistry and veterinary dentistry recognise three classes of symmetrical skeletal malocclusions: Class 1 - Neutroclussion is when the relationship between the jaws and the teeth is normal and one or more individual teeth have a malposition. Class 2 - Mandibular distocclusion is when the mandibular dental arch occludes distal or caudal to its normal position. Class 3 - Mandibular mesiocclusion is when the mandibular arch occludes rostral to the normal position (15). Crossbite in dentistry is known as inversed occlusion. Thus, maxillary circumscribing is not present. Crossbites may be rostral or caudal. This may be a consequence of a dental or skeletal malocclusion. In the rostral crossbite, the relationship between one or more incisors is inverted. Usually, it may be due to palatally positioned upper incisors and labially positioned lower incisors. Level bite is the term that describes the edge-to-edge contact between the two dental arches. Rostral-level bite refers to edge-to-edge contact between one or more incisors. The anchorage of orthodontic devices may vary from standard brackets to personalised anchorage devices. CAD-CAM methods have changed how dental devices, prosthodontics, and orthodontics are designed and made (2). Orthodontic computer-assisted planning and designs allow the team to create multiple simulations to facilitate communications between the team members, and it is more intuitive to explain to the owner. At the same time, different simulations of the future device may be obtained in less time. Using the Virtual planning systems (VPS) and three-dimensional (3D) printing, veterinary orthodontics has stepped into a new stage (13). 

Materials and methods
Twelve cases were included in the study. The criteria to be introduced in the study was rostral crossbite and rostral level bite with class 1 neutral occlusion. Eight cases presented cross-bite and four-level bites. After diagnosis and discussions with the owners about expectations, commitment, fees, and the number of appointments, minimal blood tests were taken to evaluate the general medical condition. After confirming that patients can undergo multiple general anaesthesia in the near future, impressions were taken with hand-mixed impression material with prolonged stability. Condensation silicone was used for impressions. All together with the technical team, information was exchanged to get maximum results with the computer-assisted-designed orthodontic devices. All cases received an arch metal bar anchored on the maxillary canines. The bars have buttons for elastic chains. The devices placed on teeth were metal crowns that were attached to the vestibular side hooks for elastic chains. Even more, on the incisal edge, crowns would have had an inclined plane so that in the retaining period, crowns would remain in place. Mandibular incisors were loaded with information and placed on metal crowns. If the case presented a crossbite, besides the inclined plane placed on the incisal edge, crowns would have hooks for elastic chains anchored on orthodontic implants placed between the roots of the third lower premolar. The technical team delivered the orthodontic pieces on model casts. On placement, the first activation occurred. The time between activations was at least three weeks and a maximum of four. Retainers were held for up to three months.

Results and discussions
Orthodontic treatment with orthodontic devices consists of two stages: active treatment, when forces are applied to the teeth that need to be moved, and retention. Retention consolidates the results, allowing the alveolar bone to deposition, remodel, grow, and mineralize, thus stabilising the teeth in the corrected position. Orthodontic devices used in active treatment are, in most cases, different from the ones that retain the results, named retainers. While the active devices induce resorption of the bone, retainers allow the bone to return to a physiologic state in the new position. The forces that are applied should provide enough force to move the needed teeth and have the lowest levels of complications or discomfort for the patients. (14) Two studies by Smith and Massoudi (1991, 1992) showed a correlation between the root area surfaces and the applied force (11, 12). Thus, these forces must be correlated with the dog’s weight, breed, and teeth. If the force is mild, the desired response of initiating cellular activity resorption and bone deposition will lead to physiologic movement of the teeth. When pressure increases, necrosis of the periodontal ligament will occur on the pressure side, and resorption of the root surface and poor or no bone deposition will be obtained. The orthodontic approach should be performed only when rostral crossbite and level crossbiteare associated with class 1 occlusion and never when associated with class 3 occlusion. Legendre and Peak have proposed for moving teeth universal screws, memory wires, labial and lingual arch bars, inclined planes, or even more complicated surgical interventions. (5,8) Orthodontic devices CAD-CAM designed, our choice, fitted perfectly in the oral cavity of the patients. Metal crowns offered reliable, long-term stability for the orthodontic forces and did not fall or traumatised the patient. Orthodontic implants positioned between the roots of the lower premolars (to lingualize the lower incisors) did not affect the vitality of the teeth and offered good stability for the needed period of orthodontics. They were removed at the last appointment, when the orthodontic treatment ended. Dog breeds have three types of skull conformation: long-dolichocephalic, medium-mesocephalic, and short-brachycephalic. Dolichocephalic breeds have long, narrow profiles; mesocephalic breeds have balanced, well-proportioned skulls; and brachycephalic breeds have a pronounced mandibular prognathism. These classifications are strictly medical and do not refer to breed standards Regarding the skull type, 8.33% of the patients were dolichocephalic, 41.67% were mesocephalic, and 50% were brachycephalic. These results show that the brachycephalic owners were more aware of the medical issues a brachycephalic breed would imply. Even more, as is standard in breeding, Rottweilers go in a direction where the face is getting more flattened. Three of our cases were Rottweilers. None of the rottweilers’ that addressed us had blood bonds. The median age for addressing orthodontic treatment was for brachycephalic dogs 9,8 months versus 12,33 months in mesocephalic. The median time for malocclusion correction was shorter in brachycephalic breeds, 2,8 months versus 3,33 in mesocephalic dogs. These results reside in the fact that the oldest patients, who addressed orthodontics at 24 or 26 months of age, were mesocephalic. 

Even more, bone disponibility in brachycephalic dogs is considerably less than in mesocephalic dogs, so that the movement of the teeth has a lower volume of bone that needs to be rearranged due to orthodontic forces. The youngest patient that addressed orthodontic service was 5,5 months old, and the oldest had two years and two months. Regardless of the breed, results were significantly earlier obtained if the first appointment was at a younger age. One-third of them presented level-bite, and twothirds presented cross-bite. Crossbites are considered traumatic occlusions that lead, over time, due to painful complications. Thus, in a crossbite, the upper incisors will bite on the lower ones, developing paraxial forces impinging the periodontal ligaments, causing mobility of the teeth and pain. The upper ones will develop periapical reactions due to these abnormal, increased forces. First, the vascular-nervous package of the upper incisors will be compressed; necrosis willoccur. Clinical signs will include compromised prehension of food, halitosis, mobile teeth, weight decrease, and, after a long period of suffering in silence, lost teeth. Below (Fig. 8), the table shows the evolution in time for each case. Edge-to-edge contact is even more traumatic than a crossbite. The forces developed and the unstable contacts upon the incisal edges will cause fractures, attritions, impingement of the periodontal ligament, mobility, displacement of the involved teeth, pain, halitosis, and eventually loss of teeth. Rostral crossbites may have different aetiologies, ranging from persistent deciduous teeth (4) to vicious templates of playing or growth spurts (3). The median time for correcting the level bite was 1,5 months, versus 2,75 months’ median time needed to correct the crossbite. Crossbite owners came earlier; still, the period for correction was longer. This is because a crossbite looks more unusual than a level bite, and it can be easily diagnosed by non-specialists. Ten cases were males, two females. The median age in males for addressing veterinary orthodontics was nine months, and for females, it was 6,25 months. Even though there was no significant difference in the time for correction by gender (2,75 months), the results were positive for all of the cases. The aetiology of malocclusion may vary and may be associated with dental ones, which are simple to manage, while jaw misalignment is more challenging. We approached only the ones with dental problems. None of the dogs presented at the end of the treatment any pink teeth. Pink teeth did not appear as a consequence of the orthodontic treatment. All of the dogs in the study were neutered according to the international conventions for responsible breeding.

Conclusions
The oral cavity should be examined during the veterinary doctor’s first visit. A good selection of the cases is imperative. Successful orthodontic cases require good communication between the dental team and owners. Owners’ commitment is one of the most critical factors. Virtual planning offers more precise solutions and enhances communication with the technical team and the owners. Arch bars with buttons for elastic chains are stable and offer an excellent anchoring place for moving upper incisors. Inclined planes properly maintain the vestibularization of the upper incisors. Lingualization of the lower incisors may be obtained by elastic chains anchored on orthodontic implants placed between the roots of the lower premolars. Once the maxillary incisors overlap the mandibular ones, a stable, long-term occlusion is obtained. Placing the orthodontic implants between the roots of the lower premolars requires experience and solid knowledge of the anatomical landmarks. There were two cases of overcorrection, with maxillary incisors overlapping the mandibular ones, but at six months of follow-up, the occlusion was the ideal one. This was due to the balance offered between the tongue and lips, known as a functional corridor. Orthodontic treatment in veterinary dentistry should be performed only by experienced individuals, as complications due to high forces and unstable orthodontic appliances may lead to painful accidents. Dogs with malocclusions should be removed from reproduction. Responsible breeding is mandatory. Further studies are warranted.

References
1. Bellows J., (2019), Small animal dental equipment, nd materials and techniques, 2 ed., (Ed.) Wiley-Blackwell, Hoboken, NJ, USA
2. Eissman H.S., Rudd K.D., Marrow R.M., (1980), Dental laboratory procedures in fixed partial dentures, vol.2, (Ed.) CV Mosby Co., St. Louis, MO, USA
 3. Fulton A.J., Fiani N., Verstraete F.J., (2014), Canine paediatric dentistry. Veterinary Clinics of North America: Small Animal Practice, 44(2):303-324
4. Hennet P., (1995). Orthodontics in small carnivores, InL Crsossley D.A. and Penman S., eds., Manual of Small Animal Dentistry, (Ed.) BSAVA, Gloucestershire, UK 5. Legendre L.F., (1991) Anterior crossbite correction in a dog using a lingual bar, a lingual bow, lingual buttons and elastic threads. Journal of Veterinary Dentistry. 8:21-25
 6. Lopbrise H.B., Dodd J.R., (2019), Wigg’s veterinary dentistry. Principles and practice, 2nd edition, (Ed.) Wiley Blackwell, NJ, USA
 7. Nedelea R.I., Marcus I., (2023). Some personalized approaches concerning the absence of a tooth on the dental arches in youngster dogs and cats: case report series. Revista Romana de Medicina Veterinara, 33(1):7-13
 8. Peak R.M., Lobprise H.B., Wiggs R.B., (1999), Fabrication of a labial maxillary arch bar from orthodontic wire, acrylic and orthodontic buttons. Journal of Veterinary Dentistry, 12:127-129
 9. Reiter A., Gracis M., (2018), BSAVA Manual of Canine and Feline Dentistry and Oral Surgery,
4th edition, (Ed.) BSAVA, Aberystwyth, UK
 10. Sabri R., (2008), Management of the over-retained mandibular deciduous second molars with and without permanent successors.World J Orth,9:209-220
11. Smith M.M., Massoudi L.M., (1991), Potential attachment area of the fourth maxillary premolar in dogs. Am J Vet Res, 52(4):626.
 12. Smith M.M., Massoudi L.M., (1992), Potential attachment area of the first mandibular molar in dogs. Am J Vet Res, 53(2):258
 13. Thatcher G.P., Soukup J.W., (2022), Virtual surgical planning and 3D printing in veterinary dentistry and oromaxillofacial surgery, Veterinary clinics of North America: Small animal practice, 52(1):221-234
 14. Van Leeuwen E.J., Kuijpers-Jagtman A.M., Von den Hoff J.W., Wagener F.A., Maltha J.C., (2010), Rate of orthodontic tooth movement after changing the force magnitude: an experimental study in beagle dogs. Orthodontic Craniofacial Res, 13:238-245
 15. Wiggs R.R., Lopbrise H.B., (1997), Basics of orthodontics. Veterinary Dentistry Principles and Practice, st 1 ed, (Ed.) Lipincott-Raven, Philadelphia, USA, 435- 481.