In the last years, both medicine and dentistry have come across a revolution represented by the introduction of more and more digital technologies for both diagnostic and therapeutic purposes. Additive manufacturing is a relatively new technology consisting of a computer-aided design and computer-aided manufacturing (CAD/CAM) workflow, which allows the substitution of many materials with digital data. This process requires three fundamental steps represented by the digitalization of an item through a scanner, the editing of the data acquired using a software, and the manufacturing technology to transform the digital data into a final product, respectively. This narrative review aims to discuss the recent introduction in dentistry of the abovementioned digital workflow. The main advantages and disadvantages of the process will be discussed, along with a brief description of the possible applications on orthodontics.

3D printing systems have revolutionised prototyping in the industrial field by lowering production time from days to hours and costs from thousands to just a few dollars. Today, 3D printers are no more confined to prototyping, but are increasingly employed in medical disci- plines with fascinating results, even in many aspects of otorhinolaryngology. All publications on ENT surgery, sourced through updated electronic databases (PubMed, MEDLINE, EMBASE) and published up to March 2017, were examined according to PRISMA guidelines. Overall, 121 studies fulfilled specific inclusion criteria and were included in our systematic review. Studies were classified according to the specific field of application (otologic, rhinologic, head and neck) and area of interest (surgical and preclinical education, customised surgical planning, tissue engineering and implantable prosthesis). Technological aspects, clinical implications and limits of 3D printing processes are discussed focusing on current benefits and future perspectives.

I disordini ostruttivi salivari sono infrequenti nell’età pediatrica. I recenti progressi tecnologici nel distretto della testa e del collo hanno modificato la strategia diagnostica e terapeutica dei disordini salivari. La diagnosi è oggi basata sull’eco color Doppler, sulla scialo-RMN, sulla cone beam 3D TC, mentre la litotrissia extracorporea ed intracorporea, la scialoendoscopia interventistica, la chirurgia scialoendoscopico- assistita, sono attualmente utilizzati come procedure conservative e mininvasive per la preservazione funzionale della ghiandola affetta. Abbiamo analizzato i risultati dell’esperienza clinica a lungo termine nel trattamento dei disordini ostruttivi dell’età pediatrica. Un gruppo consecutivo di 66 pazienti pediatrici (38 femmine) con sintomi salivari ostruttivi causati da parotite ricorrente pediatrica (32 pazienti), calcoli (20), stenosi duttali (5), e ranule (9) è stato incluso nello studio. 45 pazienti sono stati sottoposti a scialoendoscopia interventistica per parotite ricorrente, calcoli e stenosi, 12 pazienti sono stati sottoposti ad un ciclo di litotrissia extracorporea (ESWL), tre pazienti a chirurgia transorale scialoendoscopico-assistita, un paziente a drenaggio, sei a marsupializzazione e due a sutura della ranula. Nel 90,9% è stato raggiunto un risultato favorevole. L’approccio combinato di litotrissia salivare extracorporea e di scialoendoscopia interventistica è stato utilizzato in tre pazienti ed una procedura secondaria è stata eseguita in sette pazienti. Nessun paziente è stato sottoposto a scialoadenectomia nonostante la persistenza di modesti sintomi ostruttivi in sei pazienti. Non è stata osservata alcuna complicanza maggiore. Adottando un adeguato iter diagnostico mediante eco color Doppler delle ghiandole salivari, scialo-RMN e cone beam 3D TC, i pazienti pediatrici con disordini ostruttivi salivari possono essere efficacemente trattati con un approccio moderno mini-invasivo mediante tecniche di litotrissia extracorporea ed intracorporea, scialoendoscopia interventistica, e chirurgia transorale scialoendoscopico-assistita; questo approccio garantisce un risultato favorevole nella maggior parte dei pazienti evitando così il ricorso alla scialoadenectomia invasiva e mantenendo così la preservazione funzionale della ghiandola coinvolta.

The aim of the present study was to assess the feasibility and utility of 3D printing technology in surgical planning of a transcutaneous bone- conduction hearing device (Bonebridge®) (BB), focusing on the identification of the proper location and placement of the transducer. 3D printed (3DP) models of three human cadaveric temporal bones, previously submitted to CT scan, were created with the representation of a topographic bone thickness map and the sinus pathway on the outer surface. The 3DP model was used to detect the most suitable location for the BB. A 3DP transparent mask that faithfully reproduced the surface of both the temporal bone and the 3DP model was also developed to correctly transfer the designated BB area. The accuracy of the procedure was verified by CT scan: a radiological marker was used to evaluate the degree of correspond- ence of the transducer site between the 3DP model and the human temporal bone. The BB positioning was successfully performed on all human temporal bones, with no difficulties in finding the proper location of the transducer. A mean error of 0.13 mm was found when the transducer site of the 3DP model was compared to that of the human temporal bone. The employment of 3D printing technology in surgical planning of BB po- sitioning showed feasible results. Further studies will be required to evaluate its clinical applicability.

Interventional sialendoscopy has become the predominant therapeutic procedure for the management of obstructive salivary disorders, but only a few multicentre studies of large series of patients with a long-term follow-up have been published. This Italian multicentre study involved 1152 patients (553 females; mean age 50 years) who, after at least a clinical and ultrasonographic evaluation, underwent a total of 1342 diagnostic and interventional sialendoscopies, 44.6% of which involved the parotid gland. 12% (n = 138) of patients underwent multiple treatments. The procedure was successful in 1309 cases. In 33 cases (2.4%) the procedure could not be concluded mainly because of complete duct stenosis (21 cases). Salivary stones were the main cause of obstruction (55%), followed by ductal stenosis and anomalies (16%), mucous plugs (14.5%) and sialodochitis (4.7%). Complete therapeutic success was obtained in 92.5% of patients after one or more procedures, and was ineffective in < 8%. Untoward effects (peri and postoperative complications) were observed in 5.4% of cases. Sialendoscopy proved to be an effective, valid and safe procedure in the diagnostic and therapeutic management of non-neoplastic obstructive salivary gland diseases.