Fusion of a maxillary third molar with a supernumerary fourth
molar: a case report
Case Image
A 20-year-old Caucasian male consulted the Department of Dentoalveolar
Surgery, School of Dentistry in February 2023 due to intermittent pain
in the left side of maxilla and face. Intraoral examination revealed
probing pocket depth distally to left maxillary second molar 7mm and
bleeding on probing. No health problem arises from medical history.
Panoramic radiograph revealed impacted mandibular third molar, mesially
angulated, with medium impaction depth, abnormal shape and size in close
proximity with maxillary sinus floor (Figure 1).
Preoperatively 2gr of Amoxicillin were prescribed. Surgical extraction
took place under local anesthesia. Infiltration anesthesia with
Lidocaine 2% with 1:80000 epinephrine. A full thickness mucoperiosteal
flap was prepared and raised, and then ostectomy was performed using
surgical handpiece and sterile saline irrigation. Tooth extraction was
performed using straight and Warwick-James elevators. Valsalva maneuver
was negative. Extraction socket was flushed with saline and flap was
repositioned and sutured. Niflumic acid 250mg was prescribed for 3-5
days. Ex vivo examination of the tooth confirmed “double” tooth
diagnosis. In order to obtain as much information as possible regarding
dental anatomy, photos of all aspects of the tooth were taken and ex
vivo CBCT of the tooth was carried out (Figure 2, Figure 3).
Additionally, tooth was submerged in epoxy resin. After setting, three
sections of the tooth were cut with a low-speed precision sectioning
machine (Isomet 11-1180 Buehler, Lake Bluff, IL, USA) with water
cooling. The cut surface of each tooth specimen was ground on a
polishing machine (Jean Wirtz TG 250, Dusseldorf, Germany) with 200 rpm
under water cooling (50 mL/min) using gradually 600-, 800-, and
1000-grit silicon carbide abrasive papers (Apex S system, Buehler, Lake
Bluff, IL, USA) for 20s each. Final tooth sections were <1mm.
Tooth specimen was placed between two liner polarization filters.
Afterwards flash (Speedlight SB-700, Nikon, Japan) with softbox (Godox,
China) was held from one side and DSLR camera (D7200, Nikon, Japan) with
macro lens (Micro Nikkor 105mm, Nikon, Japan) from the other side.
Filters were crossed in different directions until intended result was
obtained (Figure 4, 5, 6). Sutures were removed after one week, healing
was unproblematic. Oral examination after six months revealed complete
healing of soft tissues.
Differential diagnosis between different subcategories of “double”
tooth is difficult. The supposition that gemination displays a single
root canal and fusion displays several root canals is controversial.
Fusion of a normal tooth with supernumeraries will still result in a
normal tooth count. Given the presence of features suggestive of both
diagnoses, this case, actually, presented a diagnostic dilemma.
Fusion of two impacted teeth apparently results in a larger dental
structure that makes extraction more invasive and inevitably raises the
possibility of complications. Close proximity of maxillary third molar
with maxillary sinus floor has to be appreciated. Fracture of maxillary
tuberosity may occur in cases with extensive ostectomy.
Alterations in tooth size and shape during initial radiographic
examination may be a primary sign of dental abnormalities. Utilizing
contemporary imaging techniques, including CBCT and dental photography,
may showcase such special dental anatomies and complement dentists’
education in this field. Dentists’ awareness will result in a meticulous
treatment planning and ensure a successful outcome.
Figure legends
Figure 1: Initial panoramic radiograph. White arrow shows impacted third
molar with small changes in size and shape
Figure 2: Images of the extracted “double” tooth from different
aspects
Figure 3: Images exported from ex vivo CBCT of extracted “double
tooth”. Shared pulp canal system is noticed.
Figure 4: Image of the first tooth section, using polarization filters,
DSLR, macro lens and flash
Figure 5: Image of the second tooth section, using polarization filters,
DSLR, macro lens and flash
Figure 6: Image of the third tooth section, using polarization filters,
DSLR, macro lens and flash