pycnodysostosis: review and case report

Vol. 63 - No. 6 MINERVA STOMATOLOGICA 229

etal dysplasia similar to osteopetrosis as it is characterised by the failure of bone to resorb. The diseases was distinguished and described by Maroteaux and Lamy in 1962.1 The word pycnodysostosis de-rives from the Greek “puknos-dys-ostosis” meaning dense abnormal bone formation. In fact, patients with this condition suffer with high bone density and are more sus-ceptible to bone fractures.

The sclerosing effect of pycnodysostosis is caused by a genetic defect occurring on chromosome 1q21 consisting in 12 muta-tions which consequently produce a mu-tation in cathepsin K causing the disease phenotype.2

Cathepsin K is a lysosomal cysteine pro-teinase that normally degrades bone pro-teins during bone resorption. It belongs to the papain family of proteases and plays an essential role in osteoclast function and thus in the degradation of protein compo-nents of bone matrix.3

This enzyme cleaves several bone matrix proteins such as collagen type I, II and os-teonectin.

According to Nishi et al. among the cathe-psin K mutations identified all appeared to obliterate its enzymatic function.4

Department of Orthodontics University of Milan, Milan, Italy

CASE REPORTSMINERVA STOMATOL 2014;63:229-37

G. FARRONATO, S. SALVADORI, F. NOLET, A. BORGONOVO, L. ESPOSITO

Pycnodysostosis: review and case report

Aim. Aim of the present study was to present a case report of a patient suffering from pyc-nodysostosis and assess how it may manifest and affect the dental/ orthodontic treatment.Methods. An 11-year-old patient who was diagnosed with pycnodysostosis at the age of 18 months, attended the orthodontics de-partment requiring treatment for extensive carious lesions, periodontal disease and se-vere crowding.Results. After an accurate radiographic, clinical and orthodontic assessment of the patient taking into consideration the sever-ity of the condition and the patient’s neces-sities, we have formulated a treatment plan, which was accepted by both the patient and parents. We took into consideration the risks and benefits of the options available and the requests of the patient.Conclusion. We have decided to opt for the extraction of teeth to relieve the crowding as this was impeding good oral hygiene and hence increasing the risk of caries and periodontal disease. Such patients must be placed under an oral hygiene prevention scheme, a treatment plan must be accurately designed and the patient must be constantly motivated.Key words: Pycnodysostosis - Orthodontic treat-ment -Craniofacial anomalies.

Pycnodysostosis is a rare inherited au-tosomal recessive osteosclerotic skel-

Corresponding author: G. Farronato, Department of Or-Department of Or-thodontics, Fondazione IRCCS Ca’ Granda, Opedale Mag-giore Policlinico, University of Milan, via Commenda 10, 20122 Milan, Italy. E-mail: [email protected]

Anno: 2014Mese: JuneVolume: 63No: 6Rivista: MINERVA STOMATOLOGICACod Rivista: MINERVA STOMATOL

Lavoro: 3765-MSTtitolo breve: Pycnodysostosisprimo autore: FARRONATOpagine: 229-37

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230 MINERVA STOMATOLOGICA June 2014

FARRONATO PyCNODySOSTOSIS

Case report

An 11-year-old male patient attended the ortho-dontics department. The patient was diagnosed with pycnodysostosis at the age of 18 months in a paediatric department. The diagnosis was initially obtained via radiological findings and later con-firmed genetically. He was referred to our clinic for an orthodontic assessment due to the severe crowd-ing present in both his maxillary and mandibular jaws.

The family history showed no genetic predis-position to the disease. A molecular diagnosis was performed on the patient and both parents were screened. A prenatal diagnosis was suggested in case of a following pregnancy.

Physical examination of the patient revealed a short stature, short fingers and hypoplastic finger-nails and the typical facial features which occur with this condition, which are: a small face, promi-nent nose and frontal bossing (Figures 1, 2).

Oral manifestations as a consequence of the condition were also evident such as delay in tooth eruption, dental crowding, high caries risk and an initial stage of periodontal disease. The patient also sustained cranial fractures at the age of two and four. Both fractures occurred as a result of minor traumatic episodes. His medical history is also sig-nificant for recurrent fractures of the right and left tibia.

The initial stage of our treatment consisted in gathering the necessary radiological information. The patient was therefore assessed orthodontically with the aid of a cephalometric analyses. According to the results the patient presented with a class III malocclusion as shown by his ANB value, which was 2.59 (Table I).

For an accurate treatment plan we decided to carry out a Cone Beam Computed Tomography (CBCT). CBCT has been successfully used to rep-resent the true 3-dimensional morphology of the cranium skeletal structures as it has reduced radia-

Studies show that within the five muta-tions which occur in cathepsin K for the expression of the disease, four lacked all protease activity. The fifth mutation re-tained protease activity but lacked colla-genase activity. Therefore, all mutations occurring in the cathepsin K proteins elim-inated activity of the enzyme towards type I collagen which is a major constituent of organic bone matrix (95%).5

Pycnodysostosis may be associated to consanguinity between the parents in 30% of cases, with equal sex distribution.

Various bone diseases should be consid-ered in the differential diagnosis of pyc-nodysostosis, particularly cleidocranial dysostosis, osteogenesis imperfecta, and osteopetrosis.1

The objective of this article was to re-port a case of a child with pycnodysostosis and to discuss the characteristic oro-facial findings of the disease and the orthodontic treatment options. The study received the approval from both the patient and par-ents.

Figure 2.—Typical hand features.Figure 1.—Typical facial features.

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PyCNODySOSTOSIS FARRONATO

fering from pycnodisostosis should be enrolled in a dental prevention program from an early age to pre-vent loss of teeth from caries and periodontitis. For such reason the patient was included in a preven-tion program in which he was followed by a dental hygienist who took plaque and bleeding scores at different intervals of the treatment to ensure the pa-tient was motivated to maintain a high standard of plaque control.

On the bases of the clinical information obtained by radiographs and of the genetic information, a treatment plan was designed. The first phase of the treatment consisted in relieving the crowding present in both his arches (Figures 5, 6). Some au-thors suggest that early orthodontic treatment to relieve crowding is an effective treatment option. However, other authors argue that due to the lack and decreased bone remodelling which occurs in such patients the treatment outcome would not be satisfactory.5 Therefore they suggest that extrac-

tion compared with CT Multislice and can be used, when necessary, for orthodontic patients 6-11 (Figure 3A-G).

The 3D cephalometric analysis (Table I) revealed an obtuse mandibular angle and measurements of the airway space indicated a minimal pharyngeal space between the uvula and the posterior pharyn-geal wall. Obstructive sleep apnea syndrome has been reported in our patient who uses at nights a home positive-airway-pressure device.

The postero-anterior skull view showed gener-alised sclerosis of the skeleton, more pronounced in the peri-orbital region and the presence of open fontanelles.

An orthopantomogram was also carried out and this revealed severe crowding, anomalies in dental positions and severe caries (Figure 4).

In fact, due to the increased risk of caries and periodontal disease such patients must be given good oral hygiene instructions. In fact, patients suf-

Table I.—�3D cephalometric values obtained using the Mimics software.

Measurements Units Pre-Op 3D

001, Go sx - Me mm 59.16002, Go dx - Me mm 60.79003, S - N mm 59.13004, PNS - A mm 38.6301, SNA deg 73.4202, SNB deg 71.9803, ANB deg 2.5904, ANS - PNS - Go sx - Me deg 44.3205, ANS - PNS - Go dx - Me deg 50.5606, S - N - ANS - PNS deg 26.1407, S - N - Go sx - Me deg 63.5708, S - N - Go dx - Me deg 64.9209, Ba - S - N deg 141.5710, Cd sx - Go sx - Me deg 144.1411, Cd dx - Go dx - Me deg 142.6212, Cd sx - Go sx - N deg 70.4713, Cd dx - Go dx- N deg 68.1714, N - Go sx - Me deg 78.8315, N - Go dx - Me deg 80.616, N - Me mm 99.2617, N - ANS mm 46.1818, ANS - Me mm 54.8319, Cd sx - Go sx mm 41.1320, Cd dx - Go dx mm 39.1421, S - Go sx mm 66.5622, S - Go dx mm 62.9323, Sor sx - Sag plane mm 22.2424, Sor dx - Sag plane mm 20.3425, Mx sx - Sag plane mm 24.4226, Mx dx - Sag plane mm 26.7627, Cd sx - Sag plane mm 43.4328, Cd dx - Sag plane mm 40.0829, Go sx- Sag plane mm 35.9130, Go dx - Sag plane mm 38.3131, Ui - Sag plane mm 6.1332, Li - Sag plane mm 1.82

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Figures 3.—A-G) CBCT images of the patient from different perspectives.

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tions are more recommendable in such cases. In this specific case we decided to extract teeth as they were also decayed and hence compromised. In order to relieve crowding, we should have ex-tracted the upper and lower second premolars and the upper and lower second and third molars. How-ever, we decided to extract the second premolars but to postpone the extractions of the second and third molars. This was done under the advice of the oral surgeon as there would be an increased risk of bone necrosis if the extractions were performed together. In fact, it is essential that extractions are carried out as atraumatically as possible to avoid the risk of infections and fractures occurring espe-cially in the mandible. The extractions of the lower second and third molars was carried out one year after the premolar extractions. It was also decided to extract the lower left first incisor as further space

Figure 6.—A-C) Patient’s dentition showing his severe crowding.

Figure 5.—A, B) MRI of the patient.

Figure 4.—OPT of the patient when he first attended.

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most serious complication of pycnodysos-tosis as inappropriate remodelling of bone by dysfunctional osteoclasts leads to brittle bone.16, 17 However, the characteristic bone brittleness worsens with age, consequently osteomyelitis is more common in adults than in children.18, 19 Deficient growth of the maxilla and mandible makes normal tooth alignment impossible, with dental crowd-ing and difficulty for the patient to maintain high standards of oral hygiene.

Orthodontic treatment to relieve crowd-ing and impaction of teeth can be accom-plished by accurately timing the extractions. For instance, the extraction of deciduous teeth can be considered in order to encour-age the eruption of the permanent teeth.20 Early intervention to reduce dental crowd-ing may also be indicated in growing pa-tients to improve the alignment of erupting permanent teeth.

In this case we opted for extractions of the teeth rather than immediate orthodontic treatment also because of the severe crowd-ing and the poor oral hygiene techniques, which could have compromised the overall success of the treatment. In spite of the in-creased bone fragility, our patient presented with adequate bone healing after the ex-tractions of the upper and lower second premolars. Therefore, growing patients with pycnodysostosis should receive spe-cial dental care, especially preventive and interceptive treatments, because of the typi-cal oral alterations described, in addition to periodical follow-up of their growth and craniofacial development. A good and pre-cise treatment plan is essential and the col-laboration between the different clinicians involved in the treatment of such patients is crucial to encourage the patient and in-crease the potential of an effective and suc-cessful outcome.

References

1. Maroteaux P, Lamy M. La Pycnodysostose. Press Med 1962;70:999-1002.

2. Johnson MR, Polymeropoulos MH, Vos HL et al. A nonsense mutation in the cathepsin K gene ob-served in a family with pycnodysostosis. Genome Res 1996;6:1050-5.

was required. Crowding was, therefore, relieved. The patient was then (and is still now) using a class III functional appliance. This appliance tends to af-fect the muscles that control jaw function and posi-tioning. It stimulates some mandibular movements in the sagittal and vertical plane. It is defined as “activator”, and produces forces that are transmitted to both bone bases and dental elements.

It is composed by an acrylic superior base plate, side and front inclined planes that stimulate man-dibular repositioning and a vestibular arch that fits distal to the canines. It also has adams clasps onto the first permanent molars for anchorage. It favours maxillary growth whilst slowing mandibu-lar growth. This appliance does not interfere with the device the patient was using at night for the obstructive sleep apnea syndrome. It was decided with the surgeon that although the case is a com-bined orthodontic surgical case, the risks, which may occur during the surgery, outweigh the ben-efits. Therefore, we have decided to treat the patient orthodontically. The patient is still undergoing or-thodontic treatment. However, it is a slower process due to the delicate bone present and difficult oral hygiene attention carried out by the patient.

Discussion

Pycnodisostosis in characterised by in-creased bone density, short stature, Osteo-sclerosis, clavicular dysplasia, delayed fu-sion of the sutures of the skull in adulthood, pectus excavatum and acro-osteolysis of the distal phalanges. The typical facial features are a prominent nose, frontal bossing, a hy-poplastic maxilla and flattened mandibular angle.12 Nielsen reported cases of pycnod-ysostosis with respiratory insufficiency and a long soft palate.13 Severe snoring caused by pharyngeal narrowing is another com-mon described symptom.14 Obstructive sleep apnea syndrome has been reported in patients with pycnodysostosis and might lead to respiratory insufficiency (15). A nor-mal life span can be expected in these pa-tients, although oral manifestations can af-fect the morbidity from this disease.

In terms of dental treatment, this should be carefully planned as complications such as jaw fractures and osteomyelitis after tooth extraction may occur. Osteomyelitis, especially in the mandible, is a difficult con-dition to treat in such patients and is the

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12. Nielsen EL. Pycnodysostosis-six cases with new symptoms and an autopsy. Acta Pediatr Scand 1974;63:437-42.

13. Muto T, yamazaki A, Takeda S, Tsuji y, Shibata T. Pharyngeal narrowing as a common feature in pyc-nodysostosis- a cephalometric study. Int J Oral Maxil-lofac Surg 2005;34:680-5.

14. O’Connell AC, Brennan MT, Francomano CA. Pycno-dysostosis: orofacial manifestations in two pediatric patients. Pediatr Dent 1998;20:204-7.

15. Scarfe WC, Farman AG. What is cone-beam CT and how does it work? Dent Clin N Am 2008;52:707-30.

16. Ludlow JB, Davies-Ludlow LE, Brooks SL, Howerton WB. Dosimetry of 3 CBCT devices for oral and max-illofacial radiology: CB mercuray, NewTom 3G and i-CAT. Dentomaxillofac Radiol 2006:35:219-26.

17. Kochel J, Meyer-Marcotty P, Strnad F, Kochel M, Stel-lzig-Eisenhauer A. 3D soft tissue analysis-part 1: sagit-tal parameters. J Orofac Orthop 2010;71:40-52.

18. Gribel BF, Gribel MN, Frazao DC, McNamara JA, Manzi FR. Accuracy and reliability of craniomet-Accuracy and reliability of craniomet-ric measurements on lateral cephalometry and 3D measurements on CBCT scans. Angle Orthodontist 2011;81:26-35.

19. Hou W, Brömme D, Zhao y, Mehler E, Dushey C, Weinstein H et al. Characterization of novel cathe-psin K mutations in the pro and mature polypep-tide regions causing pycnodysostosis. J Clin Invest 1999;103:731-8.

20. Everts V, Aronson D, Beertsen W. Phagocytosis of bone collagen by osteoclasts in two cases of pycno-dysostosis. Calcified Tissue International 1985;37:25-31.

3. Motyckova G, Weilbaecher KN, Horstmann M, Rie-man DJ, Fisher DZ, Fisher DE. Linking osteopetrosis and pycnodysostosis: regulation of cathepsin K ex-pression by the microphthalmia transcription factor family. PNAS 2001;98:5798-803.

4. Nishi y, Atley L, Eyre D, Edelson J, Superti-furga A, yasuda T et al. Determination of bone markers in pycnodysostosis: effects of cathepsin K deficiency on bone matrix degradation. Journal of Bone and Min-eral Research 1999;14(11).

5. Pereira DA, Aytés LB, Escoda CG. Pycnodysostosis. A report of 3 clinical cases. Med Oral Patol Cir Bucal 2008;13:E633-5.

6. Faure J, Oueiss A, Marchal-Sixou C, Braga J, Treil J. Three-dimensional cephalometry: applications in clinical practice and research. Orthod Fr 2008;79:13-30.

7. Kochel J, Meyer-Marcotty P, Kochel M, Schneck S, Stellzig-Eisenhauer A. 3D soft tissue analysis-part 2: vertical parameters. J Orofac Orthop 2010;71:207-20.

8. Jones CM, Rennie JS, Blinkhorn AS. Pycnodysosto-sis. A review of reported dental abnormalities and a report of the dental finding in two cases. Br Dent J 1988;164:218-20.

9. Zachariades N, Koundouris J. Maxillofacial symptoms in two patients with pyknodysostosis. J Oral Maxil-lofac Surg 1984;42:819-23.

10. Lovell WW, Winter RB, Morrissy RT, Weinstein SL. Lovell and Winter’s pediatric orthopaedics. London: Lippincott Williams and Wilkins; 2006.

11. Gorlin RJ, Coher MM Jr, Levin LS. Syndromes of the head and neck. New york: Oxford University: 1990. p. 346-7.

Picnodisostosi: review e caso clinico

La picnodisostosi è una rara patologia ereditaria autosomica recessiva ed è simile all’osteopetrosi

in quanto vi è manifestazione di fallimento del rias-sorbimento osseo.

Nel 1962 Maroteaux e Lamy hanno differenzia-to la picnodisostosi dall’osteopetrosi 1. La parola picnodisostosi deriva dal greco pukno-dys-ostosis, che significa anormale formazione ossea, infatti i pazienti affetti da questa patologia presentano una aumentata densità ossea e sono più suscettibili alle fratture ossee. L’effetto di sclerosi ossea caratteristi-co della picnodisostosi è causato da un difetto ge-netico del gene 1q21, che consiste in 12 mutazioni che conseguentemente producono una mutazione nella catepsina K responsabile delle manifestazioni fenotipiche della la malattia 2.

La catepsina K è una cisteina proteasi lisosomiale che normalmente degrada le proteine dell’osso du-rante il riassorbimento. Appartiene alla famiglia del-le proteine papaine e gioca un ruolo essenziale per il corretto funzionamento dell’attività osteoclastica e della conseguente degradazione delle componente proteica della matrice ossea 3.

Questo enzima è coinvolto nella scissione di di-verse proteine della matrice ossea cosi come il col-lagene di tipo I, II, e dell’osteonectina.

Secondo gli studi di Nielsen et al. tutte le muta-

zioni identificate a carico della catepsina K determi-nano una riduzione della attività enzimatica 4.

Studi dimostrano che delle cinque mutazioni che si verificano a livello della catepsina K e che de-terminano l’espressione della malattia, quattro di esse causano un assenza completa dell’attività enzi-matica. La quinta mutazione permette di mantene-re parte dell’attività enzimatica ma sarà comunque deficitaria l’attività a livello del collagene. Pertanto, tutte le mutazioni che si verificano a livello della catepsina K determinano una riduzione dell’attività enzimatica nei confronti dell’enzima che scinde il collagene di tipo 1 e che è un costituente principale della matrice organica dell’osso (95%) 5.

La picnodisostosi nel 30% dei casi è associata a consanguineità fra i genitori, con uguale distribuzio-ne nel sesso femminile e maschile.

Caso clinico

Un paziente maschio di 11 anni è stato inviato al nostro reparto di ortodonzia. La picnodisostosi era stata diagnosticata all’età di 18 mesi in un diparti-mento pediarico. La diagnosi è stata inizialmente ot-tenuta basandosi sulle caratteristiche radiografiche ed in seguito geneticamente confermata. Il paziente è stato riferito al nostro reparto per una valutazione

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Basandosi sulle informazioni cliniche, radiogra-fiche e genetiche che abbiamo ottenuto è stato sti-lato il piano di trattamento. L’estrazione di denti decidui può essere valutata per favorire l’eruzione dei denti permanenti ed alleviare l’affollamento (Figure 5, 6). Secondo alcuni autori un interven-to precoce per ridurre l’affollamento dentario può anche essere indicato in pazienti in crescita, per migliorare l’allineamento dei denti permanenti in eruzione. Il trattamento ortodontico per risolvere l’affollamento e l’occlusione dentaria può essere quindi compiuto programmando opportune estra-zioni. Tuttavia, altri autori ritengono che a causa del ridotto rimodellamento osseo l’estrazione dei denti decidui non sia indicata e che sia preferi-bile procedere con la successiva estrazione degli elementi dentali permanenti 5. Nel caso specifico del nostro paziente abbiamo deciso di procedere con l’estrazione degli elementi dentali in quan-to risultavano cariati e pertanto compromessi. Al fine di alleviare l’affollamento abbiamo deciso di procedere con l’estrazione dei secondi premolari superiori ed inferiori e dei secondi e terzi molari superiori ed inferiori. Tuttavia, seguendo il consi-glio del chirurgo orale si è proceduto dapprima all’estrazione dei secondi premolari e si è deciso di postporre le estrazione dei secondi e terzi molari superiori ed inferiori per ridurre il rischio di ne-crosi ossea qualora le estrazioni fossero state fatte contemporaneamente. È estremamente importante che le estrazioni siano effettuate con una tecnica il più possible atraumatica per ridurre il rischio di infezioni e fratture mandibolari. Le estrazione dei secondi e terzi molari inferiori sono stata effettuate ad una anno di distanza. É stato poi deciso di pro-cedere all’estrazione dell’incisivo centrale inferiore sinistro in quanto ulteriore spazio era necessario per alleviare l’affollamento. Il paziente è in cura con un dispositivo funzionale. É stato concordato, in associazione con il chirurgo maxillo-facciale, che sebbene il caso fosse idealmente da trattare con una soluzione ortodontico-chirurgica, i rischi che potevano verificarsi durante l’intervento chirurgico fossero superiori ai benefici. Pertanto il paziente ha iniziato un trattamento ortodontico che è ancora in fase attiva. Il trattamento ortodontico deve essere portato avanti con estrema cautela per la fragilità ossea e per le difficili manovre di igiene orale.

Discussione

Le comuni manifestazioni cliniche includono un’aumentata densità ossea, bassa statura, osteo-sclerosi, displasia clavicolare, ritardo della fusione delle suture del cranio nell’età adulta, pectus exca-vatum e acro-osteolisi delle falangi distali. Le tipiche caratteristiche faciali sono naso prominente, bozze frontali, mascellare ipoplastico e angolo mandibo-lare ottuso 12.

ortodontica dovuta alla presenza di grave affolla-mento a carico dell’arcata superiore ed inferiore.

È stata eseguita al paziente una diagnosi mole-colare ed entrambi i genitori sono stati analizzati e testati geneticamente. La storia familiare non ha individuato consanguineità fra i genitori. Una dia-gnosi prenatale è stata consigliata nel caso di una successiva gravidanza.

L’esame fisico ha rilevato bassa statura e le tipi-che caratteristiche facciali come viso piccolo, naso prominente e bozze frontali. L’esame delle mani ha rilevato dita corte e unghie ipoplastiche (Figure 1, 2).

Le manifestazioni cliniche a carico del cavo ora-le sono ritardo nell’eruzione dentale, affollamento dentale, alto rischio di carie e rischio di patologia parodontale.

Il paziente ha riportato fratture del cranio all’età di due e quattro anni. Entrambe le fratture sono sta-te causate da episodi minori traumatici. La sua storia medica è anche significante per fratture ricorrenti della tibia destra e sinistra.

La fase iniziale del trattamento è stata basata sulla documentazione radiografica basata sulla valutazio-ne della CBCT.

La CBCT permette una precisa rappresentazio-ne della morfologia tridimensionale delle strutture scheletriche e determina una minore esposizione alle radiazioni rispetto alla CT multislice e può per-tanto essere usata quando necessario nei pazieni ortodontici 6-11 (Figura 3A-G).

L’analisi cefalometrica è stata effettuata e i risul-tati mostrano una terza classe scheletrica con un valore di ANB di 2,59 (Tabella I).

L’analisi cefalometrica tridimensionale ha rivelato un angolo mandibolare aperto e la misurazione del-lo spazio aereo ha indicato uno spazio faringeo ri-dotto tra l’ugola e la parete posteriore della faringe.

Il paziente presenta la sindrome dell’apnea ostruttiva e deve fare uso notturno di un dispositivo di supporto respiratorio.

La vista del cranio postero-anteriore ha mostrato sclerosi generalizzate dello scheletro, maggiormen-te pronunciata nella regione periorbitale e fontanel-le ancora aperte.

La visione panoramica ha mostrato elevato af-follamento, malposizionamenti dentali e carie gravi (Figura 4).

Una buona igiene deve essere sottolineata in pazienti con picnodisostosi a causa della morbilità associata a carie e periodontite, è importante che questi pazienti siano coinvolti in un programma di prevenzione sin dall’età precoce per prevenire pre-mature perdite di elementi dentali e problematiche parodontali.

Il paziente è stato, infatti, inserito in un program-ma preventivo nel quale un igienista ha valutato gli indici di placca e di sanguinamento per mantenere durante la durata del trattamento ortodontico un alta motivazione alle manovre di igiene orale.

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estrazioni dei secondi premolari superiori e inferio-ri. I pazienti in crescita con picnodisostosi devono ricevere speciali cure dentarie, in paricolare tratta-menti preventivi e intercettivi, a causa delle tipiche alterazioni orali descritte, in aggiunta a follow-up periodici della loro crescita e dello sviluppo cra-niofaciale. Un piano di trattamento preciso e mul-tidisciplinare è fondamentale nei pazienti affetti da picnodisostosi.

Riassunto

Obiettivo. Lo scopo di questo lavoro consiste nel presentare un caso di picnodisostosi e di descrivere le manifestazioni odontoiatriche ed ortodontiche di questa patologia.

Metodi. Un paziente maschio di 11 anni affetto da picnodisostosi, diagnosticata all’età di 18 mesi, è stato inviato nel nostro reparto per cure odontoia-triche e ortodontiche.

Risultati. In seguito a un’accurata indagine radio-grafica e clinica siamo giunti a una diagnosi orto-dontica che teneva in considerazione la severità del quadro clinico e le necessità del paziente. É stato formulato un piano di trattamento che è stato spie-gato ed accettato dal paziente e dai genitori. Sono stati tenuti in considerazione i rischi ed i benefici delle diverse opzioni e le richieste del paziente.

Conclusioni. Il piano di trattamento prevede l’estrazione di elementi dentali per alleviare l’affol-lamento e favorire la salute parodontale e le mano-vre di igiene orale. I pazienti che crescono con Pic-nodisostosi devono ricevere speciali cure dentarie, in particolare trattamenti preventivi e intercettivi, a causa delle tipiche alterazioni a livello del cavo orale descritte in precedenza, oltre a follow-up pe-riodici della loro crescita e dello sviluppo cranio-faciale.Parole chIave: Pycnodysostosi - Trattamento orto-dontico - Anomalie craniofacciali.

Nielsen ha riportato casi di picnodisostosi con insufficienza respiratoria e palato molle lungo 13.

Un grave russamento causato da un restringi-mento della faringe è, oltretutto, descritto come sin-tomo della picnodisostosi 14.

La syndrome dell’apnea ostruttiva frequentemen-te presente in questi pazienti può portare ad insuf-ficienze respiratorie 15.

In questi pazienti vi è un’aspettativa di vita nor-male, sebbene le manifestazioni orali possano in-fluenzare la morbilità causata da questa malattia. Le complicanze che ci si aspettano durante il tratta-mento della malattia orale, come avulsioni dentarie, sono fratture della mandibola e osteomielite. L’oste-omielite, specialmente nella mandibola, è difficile da trattare in questi pazienti ed è la problematica più seria legata a un inappropriato rimodellamento osseo dovuto a osteoclasti disfunzionali 16, 17.

Dal momento che la qualità dell’osso peggiora con l’età l’oteomielite si verifica più frequentemente negli adulti che nei bambini 18, 19.

Una crescita carente del mascellare superiore e della mandibola rende impossibile un norma-le allineamento dei denti e conseguenti difficoltà nell’igiene orale.

L’estrazione di denti decidui può essere valuta-ta per favorire l’eruzione dei denti permanenti. Un intervento precoce per ridurre l’affollamento denta-rio può anche essere indicato in pazienti in crescita per migliorare l’allineamento dei denti permanenti in eruzione. Il trattamento ortodontico per risolve-re l’affollamento e l’occlusione dentaria può essere quindi compiuto programmando opportune estra-zioni 20.

In questo caso abbiamo deciso di procede con le estrazioni dei denti piuttosto che con il solo tratta-mento ortodontico a causa del severo affollamento e delle difficili manovre di igiene orale che avrebbe-ro potuto compromettere il risultato del trattamento.

Nonostante la fragilità, nel nostro paziente, la guarigione dell’osso è stata normale in seguito alle

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pycnodysostosis: review and case report

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